Cargoify servo

components/gfx/Cargo.toml

@@ -0,0 +1,62 @@
+[package]
+
+name = "gfx"
+version = "0.0.1"
+authors = ["The Servo Project Developers"]
+
+[lib]
+name = "gfx"
+path = "lib.rs"
+
+[dependencies.macros]
+path = "../macros"
+
+[dependencies.net]
+path = "../net"
+
+[dependencies.util]
+path = "../util"
+
+[dependencies.msg]
+path = "../msg"
+
+[dependencies.style]
+path = "../style"
+
+[dependencies.azure]
+git = "https://github.com/servo/rust-azure"
+
+[dependencies.geom]
+git = "https://github.com/servo/rust-geom"
+
+[dependencies.layers]
+git = "https://github.com/servo/rust-layers"
+
+[dependencies.stb_image]
+git = "https://github.com/servo/rust-stb-image"
+
+[dependencies.png]
+git = "https://github.com/servo/rust-png"
+
+[dependencies.url]
+git = "https://github.com/servo/rust-url"
+
+[dependencies.harfbuzz]
+git = "https://github.com/servo/rust-harfbuzz"
+
+[dependencies.fontconfig]
+git = "https://github.com/servo/rust-fontconfig"
+
+[dependencies.freetype]
+git = "https://github.com/servo/rust-freetype"
+
+[dependencies.core_foundation]
+git = "http://github.com/servo/rust-core-foundation"
+
+[dependencies.core_graphics]
+git = "http://github.com/servo/rust-core-graphics"
+
+[dependencies.core_text]
+git = "http://github.com/servo/rust-core-text"
+
+

components/gfx/buffer_map.rs

@@ -0,0 +1,156 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+use std::collections::hashmap::HashMap;
+use geom::size::Size2D;
+use layers::platform::surface::NativePaintingGraphicsContext;
+use layers::layers::LayerBuffer;
+use std::hash::Hash;
+use std::hash::sip::SipState;
+use std::mem;
+
+/// This is a struct used to store buffers when they are not in use.
+/// The render task can quickly query for a particular size of buffer when it
+/// needs it.
+pub struct BufferMap {
+    /// A HashMap that stores the Buffers.
+    map: HashMap<BufferKey, BufferValue>,
+    /// The current amount of memory stored by the BufferMap's buffers.
+    mem: uint,
+    /// The maximum allowed memory. Unused buffers will be deleted
+    /// when this threshold is exceeded.
+    max_mem: uint,
+    /// A monotonically increasing counter to track how recently tile sizes were used.
+    counter: uint,
+}
+
+/// A key with which to store buffers. It is based on the size of the buffer.
+#[deriving(Eq)]
+struct BufferKey([uint, ..2]);
+
+impl Hash for BufferKey {
+    fn hash(&self, state: &mut SipState) {
+        let BufferKey(ref bytes) = *self;
+        bytes.as_slice().hash(state);
+    }
+}
+
+impl PartialEq for BufferKey {
+    fn eq(&self, other: &BufferKey) -> bool {
+        let BufferKey(s) = *self;
+        let BufferKey(o) = *other;
+        s[0] == o[0] && s[1] == o[1]
+    }
+}
+
+/// Create a key from a given size
+impl BufferKey {
+    fn get(input: Size2D<uint>) -> BufferKey {
+        BufferKey([input.width, input.height])
+    }
+}
+
+/// A helper struct to keep track of buffers in the HashMap
+struct BufferValue {
+    /// An array of buffers, all the same size
+    buffers: Vec<Box<LayerBuffer>>,
+    /// The counter when this size was last requested
+    last_action: uint,
+}
+
+impl BufferMap {
+    // Creates a new BufferMap with a given buffer limit.
+    pub fn new(max_mem: uint) -> BufferMap {
+        BufferMap {
+            map: HashMap::new(),
+            mem: 0u,
+            max_mem: max_mem,
+            counter: 0u,
+        }
+    }
+
+    /// Insert a new buffer into the map.
+    pub fn insert(&mut self, graphics_context: &NativePaintingGraphicsContext, new_buffer: Box<LayerBuffer>) {
+        let new_key = BufferKey::get(new_buffer.get_size_2d());
+
+        // If all our buffers are the same size and we're already at our
+        // memory limit, no need to store this new buffer; just let it drop.
+        if self.mem + new_buffer.get_mem() > self.max_mem && self.map.len() == 1 &&
+            self.map.contains_key(&new_key) {
+            new_buffer.destroy(graphics_context);
+            return;
+        }
+
+        self.mem += new_buffer.get_mem();
+        // use lazy insertion function to prevent unnecessary allocation
+        let counter = &self.counter;
+        self.map.find_or_insert_with(new_key, |_| BufferValue {
+            buffers: vec!(),
+            last_action: *counter
+        }).buffers.push(new_buffer);
+
+        let mut opt_key: Option<BufferKey> = None;
+        while self.mem > self.max_mem {
+            let old_key = match opt_key {
+                Some(key) => key,
+                None => {
+                    match self.map.iter().min_by(|&(_, x)| x.last_action) {
+                        Some((k, _)) => *k,
+                        None => fail!("BufferMap: tried to delete with no elements in map"),
+                    }
+                }
+            };
+            if {
+                let list = &mut self.map.get_mut(&old_key).buffers;
+                let condemned_buffer = list.pop().take_unwrap();
+                self.mem -= condemned_buffer.get_mem();
+                condemned_buffer.destroy(graphics_context);
+                list.is_empty()
+            }
+            { // then
+                self.map.pop(&old_key); // Don't store empty vectors!
+                opt_key = None;
+            } else {
+                opt_key = Some(old_key);
+            }
+        }
+    }
+
+    // Try to find a buffer for the given size.
+    pub fn find(&mut self, size: Size2D<uint>) -> Option<Box<LayerBuffer>> {
+        let mut flag = false; // True if key needs to be popped after retrieval.
+        let key = BufferKey::get(size);
+        let ret = match self.map.find_mut(&key) {
+            Some(ref mut buffer_val) => {
+                buffer_val.last_action = self.counter;
+                self.counter += 1;
+
+                let buffer = buffer_val.buffers.pop().take_unwrap();
+                self.mem -= buffer.get_mem();
+                if buffer_val.buffers.is_empty() {
+                    flag = true;
+                }
+                Some(buffer)
+            }
+            None => None,
+        };
+
+        if flag {
+            self.map.pop(&key); // Don't store empty vectors!
+        }
+
+        ret
+    }
+
+    /// Destroys all buffers.
+    pub fn clear(&mut self, graphics_context: &NativePaintingGraphicsContext) {
+        let map = mem::replace(&mut self.map, HashMap::new());
+        for (_, value) in map.move_iter() {
+            for tile in value.buffers.move_iter() {
+                tile.destroy(graphics_context)
+            }
+        }
+        self.mem = 0
+    }
+}

components/gfx/color.rs

@@ -0,0 +1,21 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+use azure::AzFloat;
+use AzColor = azure::azure_hl::Color;
+
+pub type Color = AzColor;
+
+pub fn rgb(r: u8, g: u8, b: u8) -> AzColor {
+    AzColor {
+        r: (r as AzFloat) / (255.0 as AzFloat),
+        g: (g as AzFloat) / (255.0 as AzFloat),
+        b: (b as AzFloat) / (255.0 as AzFloat),
+        a: 1.0 as AzFloat
+    }
+}
+
+pub fn rgba(r: AzFloat, g: AzFloat, b: AzFloat, a: AzFloat) -> AzColor {
+    AzColor { r: r, g: g, b: b, a: a }
+}

components/gfx/display_list/mod.rs

@@ -0,0 +1,773 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+//! Servo heavily uses display lists, which are retained-mode lists of rendering commands to
+//! perform. Using a list instead of rendering elements in immediate mode allows transforms, hit
+//! testing, and invalidation to be performed using the same primitives as painting. It also allows
+//! Servo to aggressively cull invisible and out-of-bounds rendering elements, to reduce overdraw.
+//! Finally, display lists allow tiles to be farmed out onto multiple CPUs and rendered in
+//! parallel (although this benefit does not apply to GPU-based rendering).
+//!
+//! Display items describe relatively high-level drawing operations (for example, entire borders
+//! and shadows instead of lines and blur operations), to reduce the amount of allocation required.
+//! They are therefore not exactly analogous to constructs like Skia pictures, which consist of
+//! low-level drawing primitives.
+
+use color::Color;
+use render_context::RenderContext;
+use text::glyph::CharIndex;
+use text::TextRun;
+
+use collections::dlist::DList;
+use collections::dlist;
+use geom::{Point2D, Rect, SideOffsets2D, Size2D, Matrix2D};
+use libc::uintptr_t;
+use servo_net::image::base::Image;
+use servo_util::geometry::Au;
+use servo_util::range::Range;
+use std::fmt;
+use std::mem;
+use std::slice::Items;
+use style::computed_values::border_style;
+use sync::Arc;
+use std::num::Zero;
+use std::ptr;
+
+use azure::AzFloat;
+use azure::scaled_font::ScaledFont;
+use azure::azure_hl::ColorPattern;
+
+pub mod optimizer;
+
+/// An opaque handle to a node. The only safe operation that can be performed on this node is to
+/// compare it to another opaque handle or to another node.
+///
+/// Because the script task's GC does not trace layout, node data cannot be safely stored in layout
+/// data structures. Also, layout code tends to be faster when the DOM is not being accessed, for
+/// locality reasons. Using `OpaqueNode` enforces this invariant.
+#[deriving(Clone, PartialEq)]
+pub struct OpaqueNode(pub uintptr_t);
+
+impl OpaqueNode {
+    /// Returns the address of this node, for debugging purposes.
+    pub fn id(&self) -> uintptr_t {
+        let OpaqueNode(pointer) = *self;
+        pointer
+    }
+}
+
+trait ScaledFontExtensionMethods {
+    fn draw_text_into_context(&self,
+                              rctx: &RenderContext,
+                              run: &Box<TextRun>,
+                              range: &Range<CharIndex>,
+                              baseline_origin: Point2D<Au>,
+                              color: Color,
+                              antialias: bool);
+}
+
+impl ScaledFontExtensionMethods for ScaledFont {
+    fn draw_text_into_context(&self,
+                              rctx: &RenderContext,
+                              run: &Box<TextRun>,
+                              range: &Range<CharIndex>,
+                              baseline_origin: Point2D<Au>,
+                              color: Color,
+                              antialias: bool) {
+        use libc::types::common::c99::uint32_t;
+        use azure::{struct__AzDrawOptions,
+                    struct__AzGlyph,
+                    struct__AzGlyphBuffer,
+                    struct__AzPoint};
+        use azure::azure::{AzDrawTargetFillGlyphs};
+
+        let target = rctx.get_draw_target();
+        let pattern = ColorPattern::new(color);
+        let azure_pattern = pattern.azure_color_pattern;
+        assert!(azure_pattern.is_not_null());
+
+        let fields = if antialias {
+            0x0200
+        } else {
+            0
+        };
+
+        let mut options = struct__AzDrawOptions {
+            mAlpha: 1f64 as AzFloat,
+            fields: fields,
+        };
+
+        let mut origin = baseline_origin.clone();
+        let mut azglyphs = vec!();
+        azglyphs.reserve(range.length().to_uint());
+
+        for (glyphs, _offset, slice_range) in run.iter_slices_for_range(range) {
+            for (_i, glyph) in glyphs.iter_glyphs_for_char_range(&slice_range) {
+                let glyph_advance = glyph.advance();
+                let glyph_offset = glyph.offset().unwrap_or(Zero::zero());
+
+                let azglyph = struct__AzGlyph {
+                    mIndex: glyph.id() as uint32_t,
+                    mPosition: struct__AzPoint {
+                        x: (origin.x + glyph_offset.x).to_nearest_px() as AzFloat,
+                        y: (origin.y + glyph_offset.y).to_nearest_px() as AzFloat
+                    }
+                };
+                origin = Point2D(origin.x + glyph_advance, origin.y);
+                azglyphs.push(azglyph)
+            };
+        }
+
+        let azglyph_buf_len = azglyphs.len();
+        if azglyph_buf_len == 0 { return; } // Otherwise the Quartz backend will assert.
+
+        let mut glyphbuf = struct__AzGlyphBuffer {
+            mGlyphs: azglyphs.as_mut_ptr(),
+            mNumGlyphs: azglyph_buf_len as uint32_t
+        };
+
+        unsafe {
+            // TODO(Issue #64): this call needs to move into azure_hl.rs
+            AzDrawTargetFillGlyphs(target.azure_draw_target,
+                                   self.get_ref(),
+                                   &mut glyphbuf,
+                                   azure_pattern,
+                                   &mut options,
+                                   ptr::mut_null());
+        }
+    }
+}
+
+/// "Steps" as defined by CSS 2.1 § E.2.
+#[deriving(Clone, PartialEq)]
+pub enum StackingLevel {
+    /// The border and backgrounds for the root of this stacking context: steps 1 and 2.
+    BackgroundAndBordersStackingLevel,
+    /// Borders and backgrounds for block-level descendants: step 4.
+    BlockBackgroundsAndBordersStackingLevel,
+    /// Floats: step 5. These are treated as pseudo-stacking contexts.
+    FloatStackingLevel,
+    /// All other content.
+    ContentStackingLevel,
+    /// Positioned descendant stacking contexts, along with their `z-index` levels.
+    ///
+    /// TODO(pcwalton): `z-index` should be the actual CSS property value in order to handle
+    /// `auto`, not just an integer.
+    PositionedDescendantStackingLevel(i32)
+}
+
+impl StackingLevel {
+    pub fn from_background_and_border_level(level: BackgroundAndBorderLevel) -> StackingLevel {
+        match level {
+            RootOfStackingContextLevel => BackgroundAndBordersStackingLevel,
+            BlockLevel => BlockBackgroundsAndBordersStackingLevel,
+            ContentLevel => ContentStackingLevel,
+        }
+    }
+}
+
+struct StackingContext {
+    /// The border and backgrounds for the root of this stacking context: steps 1 and 2.
+    pub background_and_borders: DisplayList,
+    /// Borders and backgrounds for block-level descendants: step 4.
+    pub block_backgrounds_and_borders: DisplayList,
+    /// Floats: step 5. These are treated as pseudo-stacking contexts.
+    pub floats: DisplayList,
+    /// All other content.
+    pub content: DisplayList,
+    /// Positioned descendant stacking contexts, along with their `z-index` levels.
+    ///
+    /// TODO(pcwalton): `z-index` should be the actual CSS property value in order to handle
+    /// `auto`, not just an integer.
+    pub positioned_descendants: Vec<(i32, DisplayList)>,
+}
+
+impl StackingContext {
+    /// Creates a stacking context from a display list.
+    fn new(list: DisplayList) -> StackingContext {
+        let DisplayList {
+            list: list
+        } = list;
+
+        let mut stacking_context = StackingContext {
+            background_and_borders: DisplayList::new(),
+            block_backgrounds_and_borders: DisplayList::new(),
+            floats: DisplayList::new(),
+            content: DisplayList::new(),
+            positioned_descendants: Vec::new(),
+        };
+
+        for item in list.move_iter() {
+            match item {
+                ClipDisplayItemClass(box ClipDisplayItem {
+                    base: base,
+                    children: sublist
+                }) => {
+                    let sub_stacking_context = StackingContext::new(sublist);
+                    stacking_context.merge_with_clip(sub_stacking_context, &base.bounds, base.node)
+                }
+                item => {
+                    match item.base().level {
+                        BackgroundAndBordersStackingLevel => {
+                            stacking_context.background_and_borders.push(item)
+                        }
+                        BlockBackgroundsAndBordersStackingLevel => {
+                            stacking_context.block_backgrounds_and_borders.push(item)
+                        }
+                        FloatStackingLevel => stacking_context.floats.push(item),
+                        ContentStackingLevel => stacking_context.content.push(item),
+                        PositionedDescendantStackingLevel(z_index) => {
+                            match stacking_context.positioned_descendants
+                                                  .mut_iter()
+                                                  .find(|& &(z, _)| z_index == z) {
+                                Some(&(_, ref mut my_list)) => {
+                                    my_list.push(item);
+                                    continue
+                                }
+                                None => {}
+                            }
+
+                            let mut new_list = DisplayList::new();
+                            new_list.list.push(item);
+                            stacking_context.positioned_descendants.push((z_index, new_list))
+                        }
+                    }
+                }
+            }
+        }
+
+        stacking_context
+    }
+
+    /// Merges another stacking context into this one, with the given clipping rectangle and DOM
+    /// node that supplies it.
+    fn merge_with_clip(&mut self,
+                       other: StackingContext,
+                       clip_rect: &Rect<Au>,
+                       clipping_dom_node: OpaqueNode) {
+        let StackingContext {
+            background_and_borders,
+            block_backgrounds_and_borders,
+            floats,
+            content,
+            positioned_descendants: positioned_descendants
+        } = other;
+
+        let push = |destination: &mut DisplayList, source: DisplayList, level| {
+            if !source.is_empty() {
+                let base = BaseDisplayItem::new(*clip_rect, clipping_dom_node, level);
+                destination.push(ClipDisplayItemClass(box ClipDisplayItem::new(base, source)))
+            }
+        };
+
+        push(&mut self.background_and_borders,
+             background_and_borders,
+             BackgroundAndBordersStackingLevel);
+        push(&mut self.block_backgrounds_and_borders,
+             block_backgrounds_and_borders,
+             BlockBackgroundsAndBordersStackingLevel);
+        push(&mut self.floats, floats, FloatStackingLevel);
+        push(&mut self.content, content, ContentStackingLevel);
+
+        for (z_index, list) in positioned_descendants.move_iter() {
+            match self.positioned_descendants
+                      .mut_iter()
+                      .find(|& &(existing_z_index, _)| z_index == existing_z_index) {
+                Some(&(_, ref mut existing_list)) => {
+                    push(existing_list, list, PositionedDescendantStackingLevel(z_index));
+                    continue
+                }
+                None => {}
+            }
+
+            let mut new_list = DisplayList::new();
+            push(&mut new_list, list, PositionedDescendantStackingLevel(z_index));
+            self.positioned_descendants.push((z_index, new_list));
+        }
+    }
+}
+
+/// Which level to place backgrounds and borders in.
+pub enum BackgroundAndBorderLevel {
+    RootOfStackingContextLevel,
+    BlockLevel,
+    ContentLevel,
+}
+
+/// A list of rendering operations to be performed.
+#[deriving(Clone)]
+pub struct DisplayList {
+    pub list: DList<DisplayItem>,
+}
+
+pub enum DisplayListIterator<'a> {
+    EmptyDisplayListIterator,
+    ParentDisplayListIterator(Items<'a,DisplayList>),
+}
+
+impl<'a> Iterator<&'a DisplayList> for DisplayListIterator<'a> {
+    #[inline]
+    fn next(&mut self) -> Option<&'a DisplayList> {
+        match *self {
+            EmptyDisplayListIterator => None,
+            ParentDisplayListIterator(ref mut subiterator) => subiterator.next(),
+        }
+    }
+}
+
+impl DisplayList {
+    /// Creates a new display list.
+    pub fn new() -> DisplayList {
+        DisplayList {
+            list: DList::new(),
+        }
+    }
+
+    /// Appends the given item to the display list.
+    pub fn push(&mut self, item: DisplayItem) {
+        self.list.push(item)
+    }
+
+    /// Appends the given display list to this display list, consuming the other display list in
+    /// the process.
+    pub fn push_all_move(&mut self, other: DisplayList) {
+        self.list.append(other.list)
+    }
+
+    pub fn debug(&self) {
+        if log_enabled!(::log::DEBUG) {
+            for item in self.list.iter() {
+                item.debug_with_level(0);
+            }
+        }
+    }
+
+    /// Draws the display list into the given render context. The display list must be flattened
+    /// first for correct painting.
+    pub fn draw_into_context(&self, render_context: &mut RenderContext,
+                             current_transform: &Matrix2D<AzFloat>) {
+        debug!("Beginning display list.");
+        for item in self.list.iter() {
+            item.draw_into_context(render_context, current_transform)
+        }
+        debug!("Ending display list.");
+    }
+
+    /// Returns a preorder iterator over the given display list.
+    pub fn iter<'a>(&'a self) -> DisplayItemIterator<'a> {
+        ParentDisplayItemIterator(self.list.iter())
+    }
+
+    /// Returns true if this list is empty and false otherwise.
+    fn is_empty(&self) -> bool {
+        self.list.len() == 0
+    }
+
+    /// Flattens a display list into a display list with a single stacking level according to the
+    /// steps in CSS 2.1 § E.2.
+    ///
+    /// This must be called before `draw_into_context()` is for correct results.
+    pub fn flatten(self, resulting_level: StackingLevel) -> DisplayList {
+        // TODO(pcwalton): Sort positioned children according to z-index.
+
+        let mut result = DisplayList::new();
+        let StackingContext {
+            background_and_borders,
+            block_backgrounds_and_borders,
+            floats,
+            content,
+            positioned_descendants: mut positioned_descendants
+        } = StackingContext::new(self);
+
+        // Steps 1 and 2: Borders and background for the root.
+        result.push_all_move(background_and_borders);
+
+        // TODO(pcwalton): Sort positioned children according to z-index.
+
+        // Step 3: Positioned descendants with negative z-indices.
+        for &(ref mut z_index, ref mut list) in positioned_descendants.mut_iter() {
+            if *z_index < 0 {
+                result.push_all_move(mem::replace(list, DisplayList::new()))
+            }
+        }
+
+        // Step 4: Block backgrounds and borders.
+        result.push_all_move(block_backgrounds_and_borders);
+
+        // Step 5: Floats.
+        result.push_all_move(floats);
+
+        // TODO(pcwalton): Step 6: Inlines that generate stacking contexts.
+
+        // Step 7: Content.
+        result.push_all_move(content);
+
+        // Steps 8 and 9: Positioned descendants with nonnegative z-indices.
+        for &(ref mut z_index, ref mut list) in positioned_descendants.mut_iter() {
+            if *z_index >= 0 {
+                result.push_all_move(mem::replace(list, DisplayList::new()))
+            }
+        }
+
+        // TODO(pcwalton): Step 10: Outlines.
+
+        result.set_stacking_level(resulting_level);
+        result
+    }
+
+    /// Sets the stacking level for this display list and all its subitems.
+    fn set_stacking_level(&mut self, new_level: StackingLevel) {
+        for item in self.list.mut_iter() {
+            item.mut_base().level = new_level;
+            match item.mut_sublist() {
+                None => {}
+                Some(sublist) => sublist.set_stacking_level(new_level),
+            }
+        }
+    }
+}
+
+/// One drawing command in the list.
+#[deriving(Clone)]
+pub enum DisplayItem {
+    SolidColorDisplayItemClass(Box<SolidColorDisplayItem>),
+    TextDisplayItemClass(Box<TextDisplayItem>),
+    ImageDisplayItemClass(Box<ImageDisplayItem>),
+    BorderDisplayItemClass(Box<BorderDisplayItem>),
+    LineDisplayItemClass(Box<LineDisplayItem>),
+    ClipDisplayItemClass(Box<ClipDisplayItem>),
+
+    /// A pseudo-display item that exists only so that queries like `ContentBoxQuery` and
+    /// `ContentBoxesQuery` can be answered.
+    ///
+    /// FIXME(pcwalton): This is really bogus. Those queries should not consult the display list
+    /// but should instead consult the flow/box tree.
+    PseudoDisplayItemClass(Box<BaseDisplayItem>),
+}
+
+/// Information common to all display items.
+#[deriving(Clone)]
+pub struct BaseDisplayItem {
+    /// The boundaries of the display item.
+    ///
+    /// TODO: Which coordinate system should this use?
+    pub bounds: Rect<Au>,
+
+    /// The originating DOM node.
+    pub node: OpaqueNode,
+
+    /// The stacking level in which this display item lives.
+    pub level: StackingLevel,
+}
+
+impl BaseDisplayItem {
+    pub fn new(bounds: Rect<Au>, node: OpaqueNode, level: StackingLevel) -> BaseDisplayItem {
+        BaseDisplayItem {
+            bounds: bounds,
+            node: node,
+            level: level,
+        }
+    }
+}
+
+/// Renders a solid color.
+#[deriving(Clone)]
+pub struct SolidColorDisplayItem {
+    pub base: BaseDisplayItem,
+    pub color: Color,
+}
+
+/// Renders text.
+#[deriving(Clone)]
+pub struct TextDisplayItem {
+    /// Fields common to all display items.
+    pub base: BaseDisplayItem,
+
+    /// The text run.
+    pub text_run: Arc<Box<TextRun>>,
+
+    /// The range of text within the text run.
+    pub range: Range<CharIndex>,
+
+    /// The color of the text.
+    pub text_color: Color,
+
+    pub baseline_origin: Point2D<Au>,
+    pub orientation: TextOrientation,
+}
+
+#[deriving(Clone, Eq, PartialEq)]
+pub enum TextOrientation {
+    Upright,
+    SidewaysLeft,
+    SidewaysRight,
+}
+
+/// Renders an image.
+#[deriving(Clone)]
+pub struct ImageDisplayItem {
+    pub base: BaseDisplayItem,
+    pub image: Arc<Box<Image>>,
+
+    /// The dimensions to which the image display item should be stretched. If this is smaller than
+    /// the bounds of this display item, then the image will be repeated in the appropriate
+    /// direction to tile the entire bounds.
+    pub stretch_size: Size2D<Au>,
+}
+
+/// Renders a border.
+#[deriving(Clone)]
+pub struct BorderDisplayItem {
+    pub base: BaseDisplayItem,
+
+    /// The border widths
+    pub border: SideOffsets2D<Au>,
+
+    /// The border colors.
+    pub color: SideOffsets2D<Color>,
+
+    /// The border styles.
+    pub style: SideOffsets2D<border_style::T>
+}
+
+/// Renders a line segment.
+#[deriving(Clone)]
+pub struct LineDisplayItem {
+    pub base: BaseDisplayItem,
+
+    /// The line segment color.
+    pub color: Color,
+
+    /// The line segment style.
+    pub style: border_style::T
+}
+
+/// Clips a list of child display items to this display item's boundaries.
+#[deriving(Clone)]
+pub struct ClipDisplayItem {
+    /// The base information.
+    pub base: BaseDisplayItem,
+
+    /// The child nodes.
+    pub children: DisplayList,
+}
+
+impl ClipDisplayItem {
+    pub fn new(base: BaseDisplayItem, children: DisplayList) -> ClipDisplayItem {
+        ClipDisplayItem {
+            base: base,
+            children: children,
+        }
+    }
+}
+
+pub enum DisplayItemIterator<'a> {
+    EmptyDisplayItemIterator,
+    ParentDisplayItemIterator(dlist::Items<'a,DisplayItem>),
+}
+
+impl<'a> Iterator<&'a DisplayItem> for DisplayItemIterator<'a> {
+    #[inline]
+    fn next(&mut self) -> Option<&'a DisplayItem> {
+        match *self {
+            EmptyDisplayItemIterator => None,
+            ParentDisplayItemIterator(ref mut subiterator) => subiterator.next(),
+        }
+    }
+}
+
+impl DisplayItem {
+    /// Renders this display item into the given render context.
+    fn draw_into_context(&self, render_context: &mut RenderContext,
+                         current_transform: &Matrix2D<AzFloat>) {
+        // This should have been flattened to the content stacking level first.
+        assert!(self.base().level == ContentStackingLevel);
+
+        match *self {
+            SolidColorDisplayItemClass(ref solid_color) => {
+                render_context.draw_solid_color(&solid_color.base.bounds, solid_color.color)
+            }
+
+            ClipDisplayItemClass(ref clip) => {
+                render_context.draw_push_clip(&clip.base.bounds);
+                for item in clip.children.iter() {
+                    (*item).draw_into_context(render_context, current_transform);
+                }
+                render_context.draw_pop_clip();
+            }
+
+            TextDisplayItemClass(ref text) => {
+                debug!("Drawing text at {}.", text.base.bounds);
+
+                // Optimization: Don’t set a transform matrix for upright text,
+                // and pass a strart point to `draw_text_into_context`.
+                // For sideways text, it’s easier to do the rotation such that its center
+                // (the baseline’s start point) is at (0, 0) coordinates.
+                let baseline_origin = match text.orientation {
+                    Upright => text.baseline_origin,
+                    SidewaysLeft => {
+                        let x = text.baseline_origin.x.to_nearest_px() as AzFloat;
+                        let y = text.baseline_origin.y.to_nearest_px() as AzFloat;
+                        render_context.draw_target.set_transform(&current_transform.mul(
+                            &Matrix2D::new(
+                                0., -1.,
+                                1., 0.,
+                                x, y
+                            )
+                        ));
+                        Zero::zero()
+                    },
+                    SidewaysRight => {
+                        let x = text.baseline_origin.x.to_nearest_px() as AzFloat;
+                        let y = text.baseline_origin.y.to_nearest_px() as AzFloat;
+                        render_context.draw_target.set_transform(&current_transform.mul(
+                            &Matrix2D::new(
+                                0., 1.,
+                                -1., 0.,
+                                x, y
+                            )
+                        ));
+                        Zero::zero()
+                    }
+                };
+
+                render_context.font_ctx.get_render_font_from_template(
+                    &text.text_run.font_template,
+                    text.text_run.pt_size,
+                    render_context.opts.render_backend
+                ).borrow().draw_text_into_context(
+                    render_context,
+                    &*text.text_run,
+                    &text.range,
+                    baseline_origin,
+                    text.text_color,
+                    render_context.opts.enable_text_antialiasing
+                );
+
+                // Undo the transform, only when we did one.
+                if text.orientation != Upright {
+                    render_context.draw_target.set_transform(current_transform)
+                }
+            }
+
+            ImageDisplayItemClass(ref image_item) => {
+                debug!("Drawing image at {:?}.", image_item.base.bounds);
+
+                let mut y_offset = Au(0);
+                while y_offset < image_item.base.bounds.size.height {
+                    let mut x_offset = Au(0);
+                    while x_offset < image_item.base.bounds.size.width {
+                        let mut bounds = image_item.base.bounds;
+                        bounds.origin.x = bounds.origin.x + x_offset;
+                        bounds.origin.y = bounds.origin.y + y_offset;
+                        bounds.size = image_item.stretch_size;
+
+                        render_context.draw_image(bounds, image_item.image.clone());
+
+                        x_offset = x_offset + image_item.stretch_size.width;
+                    }
+
+                    y_offset = y_offset + image_item.stretch_size.height;
+                }
+            }
+
+            BorderDisplayItemClass(ref border) => {
+                render_context.draw_border(&border.base.bounds,
+                                           border.border,
+                                           border.color,
+                                           border.style)
+            }
+
+            LineDisplayItemClass(ref line) => {
+                render_context.draw_line(&line.base.bounds,
+                                          line.color,
+                                          line.style)
+            }
+
+            PseudoDisplayItemClass(_) => {}
+        }
+    }
+
+    pub fn base<'a>(&'a self) -> &'a BaseDisplayItem {
+        match *self {
+            SolidColorDisplayItemClass(ref solid_color) => &solid_color.base,
+            TextDisplayItemClass(ref text) => &text.base,
+            ImageDisplayItemClass(ref image_item) => &image_item.base,
+            BorderDisplayItemClass(ref border) => &border.base,
+            LineDisplayItemClass(ref line) => &line.base,
+            ClipDisplayItemClass(ref clip) => &clip.base,
+            PseudoDisplayItemClass(ref base) => &**base,
+        }
+    }
+
+    pub fn mut_base<'a>(&'a mut self) -> &'a mut BaseDisplayItem {
+        match *self {
+            SolidColorDisplayItemClass(ref mut solid_color) => &mut solid_color.base,
+            TextDisplayItemClass(ref mut text) => &mut text.base,
+            ImageDisplayItemClass(ref mut image_item) => &mut image_item.base,
+            BorderDisplayItemClass(ref mut border) => &mut border.base,
+            LineDisplayItemClass(ref mut line) => &mut line.base,
+            ClipDisplayItemClass(ref mut clip) => &mut clip.base,
+            PseudoDisplayItemClass(ref mut base) => &mut **base,
+        }
+    }
+
+    pub fn bounds(&self) -> Rect<Au> {
+        self.base().bounds
+    }
+
+    pub fn children<'a>(&'a self) -> DisplayItemIterator<'a> {
+        match *self {
+            ClipDisplayItemClass(ref clip) => ParentDisplayItemIterator(clip.children.list.iter()),
+            SolidColorDisplayItemClass(..) |
+            TextDisplayItemClass(..) |
+            ImageDisplayItemClass(..) |
+            BorderDisplayItemClass(..) |
+            LineDisplayItemClass(..) |
+            PseudoDisplayItemClass(..) => EmptyDisplayItemIterator,
+        }
+    }
+
+    /// Returns a mutable reference to the sublist contained within this display list item, if any.
+    fn mut_sublist<'a>(&'a mut self) -> Option<&'a mut DisplayList> {
+        match *self {
+            ClipDisplayItemClass(ref mut clip) => Some(&mut clip.children),
+            SolidColorDisplayItemClass(..) |
+            TextDisplayItemClass(..) |
+            ImageDisplayItemClass(..) |
+            BorderDisplayItemClass(..) |
+            LineDisplayItemClass(..) |
+            PseudoDisplayItemClass(..) => None,
+        }
+    }
+
+    pub fn debug_with_level(&self, level: uint) {
+        let mut indent = String::new();
+        for _ in range(0, level) {
+            indent.push_str("| ")
+        }
+        debug!("{}+ {}", indent, self);
+        for child in self.children() {
+            child.debug_with_level(level + 1);
+        }
+    }
+}
+
+impl fmt::Show for DisplayItem {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "{} @ {} ({:x})",
+            match *self {
+                SolidColorDisplayItemClass(_) => "SolidColor",
+                TextDisplayItemClass(_) => "Text",
+                ImageDisplayItemClass(_) => "Image",
+                BorderDisplayItemClass(_) => "Border",
+                LineDisplayItemClass(_) => "Line",
+                ClipDisplayItemClass(_) => "Clip",
+                PseudoDisplayItemClass(_) => "Pseudo",
+            },
+            self.base().bounds,
+            self.base().node.id(),
+        )
+    }
+}

components/gfx/display_list/optimizer.rs

@@ -0,0 +1,73 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+use display_list::{BorderDisplayItemClass, ClipDisplayItem, ClipDisplayItemClass, DisplayItem};
+use display_list::{DisplayList, ImageDisplayItemClass, LineDisplayItemClass};
+use display_list::{PseudoDisplayItemClass, SolidColorDisplayItemClass, TextDisplayItemClass};
+
+use collections::dlist::DList;
+use geom::rect::Rect;
+use servo_util::geometry::Au;
+use sync::Arc;
+
+pub struct DisplayListOptimizer {
+    display_list: Arc<DisplayList>,
+    /// The visible rect in page coordinates.
+    visible_rect: Rect<Au>,
+}
+
+impl DisplayListOptimizer {
+    /// `visible_rect` specifies the visible rect in page coordinates.
+    pub fn new(display_list: Arc<DisplayList>, visible_rect: Rect<Au>) -> DisplayListOptimizer {
+        DisplayListOptimizer {
+            display_list: display_list,
+            visible_rect: visible_rect,
+        }
+    }
+
+    pub fn optimize(self) -> DisplayList {
+        self.process_display_list(&*self.display_list)
+    }
+
+    fn process_display_list(&self, display_list: &DisplayList) -> DisplayList {
+        let mut result = DList::new();
+        for item in display_list.iter() {
+            match self.process_display_item(item) {
+                None => {}
+                Some(display_item) => result.push(display_item),
+            }
+        }
+        DisplayList {
+            list: result,
+        }
+    }
+
+    fn process_display_item(&self, display_item: &DisplayItem) -> Option<DisplayItem> {
+        // Eliminate display items outside the visible region.
+        if !self.visible_rect.intersects(&display_item.base().bounds) {
+            return None
+        }
+
+        // Recur.
+        match *display_item {
+            ClipDisplayItemClass(ref clip) => {
+                let new_children = self.process_display_list(&clip.children);
+                if new_children.is_empty() {
+                    return None
+                }
+                Some(ClipDisplayItemClass(box ClipDisplayItem {
+                    base: clip.base.clone(),
+                    children: new_children,
+                }))
+            }
+
+            BorderDisplayItemClass(_) | ImageDisplayItemClass(_) | LineDisplayItemClass(_) |
+            PseudoDisplayItemClass(_) | SolidColorDisplayItemClass(_) |
+            TextDisplayItemClass(_) => {
+                Some((*display_item).clone())
+            }
+        }
+    }
+}
+

components/gfx/font.rs

@@ -0,0 +1,213 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+use geom::{Point2D, Rect, Size2D};
+use std::mem;
+use std::string;
+use std::rc::Rc;
+use std::cell::RefCell;
+use servo_util::cache::{Cache, HashCache};
+use style::computed_values::{font_weight, font_style};
+use sync::Arc;
+
+use servo_util::geometry::Au;
+use platform::font_context::FontContextHandle;
+use platform::font::{FontHandle, FontTable};
+use text::glyph::{GlyphStore, GlyphId};
+use text::shaping::ShaperMethods;
+use text::{Shaper, TextRun};
+use font_template::FontTemplateDescriptor;
+use platform::font_template::FontTemplateData;
+
+// FontHandle encapsulates access to the platform's font API,
+// e.g. quartz, FreeType. It provides access to metrics and tables
+// needed by the text shaper as well as access to the underlying font
+// resources needed by the graphics layer to draw glyphs.
+
+pub trait FontHandleMethods {
+    fn new_from_template(fctx: &FontContextHandle, template: Arc<FontTemplateData>, pt_size: Option<f64>)
+                    -> Result<Self,()>;
+    fn get_template(&self) -> Arc<FontTemplateData>;
+    fn family_name(&self) -> String;
+    fn face_name(&self) -> String;
+    fn is_italic(&self) -> bool;
+    fn boldness(&self) -> font_weight::T;
+
+    fn glyph_index(&self, codepoint: char) -> Option<GlyphId>;
+    fn glyph_h_advance(&self, GlyphId) -> Option<FractionalPixel>;
+    fn glyph_h_kerning(&self, GlyphId, GlyphId) -> FractionalPixel;
+    fn get_metrics(&self) -> FontMetrics;
+    fn get_table_for_tag(&self, FontTableTag) -> Option<FontTable>;
+}
+
+// Used to abstract over the shaper's choice of fixed int representation.
+pub type FractionalPixel = f64;
+
+pub type FontTableTag = u32;
+
+pub trait FontTableTagConversions {
+    fn tag_to_str(&self) -> String;
+}
+
+impl FontTableTagConversions for FontTableTag {
+    fn tag_to_str(&self) -> String {
+        unsafe {
+            let reversed = string::raw::from_buf_len(mem::transmute(self), 4);
+            return String::from_chars([reversed.as_slice().char_at(3),
+                                       reversed.as_slice().char_at(2),
+                                       reversed.as_slice().char_at(1),
+                                       reversed.as_slice().char_at(0)]);
+        }
+    }
+}
+
+pub trait FontTableMethods {
+    fn with_buffer(&self, |*const u8, uint|);
+}
+
+#[deriving(Clone)]
+pub struct FontMetrics {
+    pub underline_size:   Au,
+    pub underline_offset: Au,
+    pub strikeout_size:   Au,
+    pub strikeout_offset: Au,
+    pub leading:          Au,
+    pub x_height:         Au,
+    pub em_size:          Au,
+    pub ascent:           Au,
+    pub descent:          Au,
+    pub max_advance:      Au,
+    pub line_gap:         Au,
+}
+
+// TODO(Issue #179): eventually this will be split into the specified
+// and used font styles.  specified contains uninterpreted CSS font
+// property values, while 'used' is attached to gfx::Font to descript
+// the instance's properties.
+//
+// For now, the cases are differentiated with a typedef
+#[deriving(Clone, PartialEq)]
+pub struct FontStyle {
+    pub pt_size: f64,
+    pub weight: font_weight::T,
+    pub style: font_style::T,
+    pub families: Vec<String>,
+    // TODO(Issue #198): font-stretch, text-decoration, font-variant, size-adjust
+}
+
+pub type SpecifiedFontStyle = FontStyle;
+pub type UsedFontStyle = FontStyle;
+
+pub struct Font {
+    pub handle: FontHandle,
+    pub metrics: FontMetrics,
+    pub descriptor: FontTemplateDescriptor,
+    pub pt_size: f64,
+    pub shaper: Option<Shaper>,
+    pub shape_cache: HashCache<String, Arc<GlyphStore>>,
+    pub glyph_advance_cache: HashCache<u32, FractionalPixel>,
+}
+
+impl Font {
+    pub fn shape_text(&mut self, text: String, is_whitespace: bool) -> Arc<GlyphStore> {
+        self.make_shaper();
+        let shaper = &self.shaper;
+        self.shape_cache.find_or_create(&text, |txt| {
+            let mut glyphs = GlyphStore::new(text.as_slice().char_len() as int, is_whitespace);
+            shaper.get_ref().shape_text(txt.as_slice(), &mut glyphs);
+            Arc::new(glyphs)
+        })
+    }
+
+    fn make_shaper<'a>(&'a mut self) -> &'a Shaper {
+        // fast path: already created a shaper
+        match self.shaper {
+            Some(ref shaper) => {
+                let s: &'a Shaper = shaper;
+                return s;
+            },
+            None => {}
+        }
+
+        let shaper = Shaper::new(self);
+        self.shaper = Some(shaper);
+        self.shaper.get_ref()
+    }
+
+    pub fn get_table_for_tag(&self, tag: FontTableTag) -> Option<FontTable> {
+        let result = self.handle.get_table_for_tag(tag);
+        let status = if result.is_some() { "Found" } else { "Didn't find" };
+
+        debug!("{:s} font table[{:s}] with family={}, face={}",
+               status, tag.tag_to_str(),
+               self.handle.family_name(), self.handle.face_name());
+
+        return result;
+    }
+
+    pub fn glyph_index(&self, codepoint: char) -> Option<GlyphId> {
+        self.handle.glyph_index(codepoint)
+    }
+
+    pub fn glyph_h_kerning(&mut self, first_glyph: GlyphId, second_glyph: GlyphId) -> FractionalPixel {
+        self.handle.glyph_h_kerning(first_glyph, second_glyph)
+    }
+
+    pub fn glyph_h_advance(&mut self, glyph: GlyphId) -> FractionalPixel {
+        let handle = &self.handle;
+        self.glyph_advance_cache.find_or_create(&glyph, |glyph| {
+            match handle.glyph_h_advance(*glyph) {
+                Some(adv) => adv,
+                None => 10f64 as FractionalPixel // FIXME: Need fallback strategy
+            }
+        })
+    }
+}
+
+pub struct FontGroup {
+    pub fonts: Vec<Rc<RefCell<Font>>>,
+}
+
+impl FontGroup {
+    pub fn new(fonts: Vec<Rc<RefCell<Font>>>) -> FontGroup {
+        FontGroup {
+            fonts: fonts
+        }
+    }
+
+    pub fn create_textrun(&self, text: String) -> TextRun {
+        assert!(self.fonts.len() > 0);
+
+        // TODO(Issue #177): Actually fall back through the FontGroup when a font is unsuitable.
+        TextRun::new(&mut *self.fonts[0].borrow_mut(), text.clone())
+    }
+}
+
+pub struct RunMetrics {
+    // may be negative due to negative width (i.e., kerning of '.' in 'P.T.')
+    pub advance_width: Au,
+    pub ascent: Au, // nonzero
+    pub descent: Au, // nonzero
+    // this bounding box is relative to the left origin baseline.
+    // so, bounding_box.position.y = -ascent
+    pub bounding_box: Rect<Au>
+}
+
+impl RunMetrics {
+    pub fn new(advance: Au, ascent: Au, descent: Au) -> RunMetrics {
+        let bounds = Rect(Point2D(Au(0), -ascent),
+                          Size2D(advance, ascent + descent));
+
+        // TODO(Issue #125): support loose and tight bounding boxes; using the
+        // ascent+descent and advance is sometimes too generous and
+        // looking at actual glyph extents can yield a tighter box.
+
+        RunMetrics {
+            advance_width: advance,
+            bounding_box: bounds,
+            ascent: ascent,
+            descent: descent,
+        }
+    }
+}

components/gfx/font_cache_task.rs

@@ -0,0 +1,276 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+use platform::font_list::get_available_families;
+use platform::font_list::get_variations_for_family;
+use platform::font_list::get_last_resort_font_families;
+use platform::font_context::FontContextHandle;
+
+use std::collections::HashMap;
+use sync::Arc;
+use font_template::{FontTemplate, FontTemplateDescriptor};
+use platform::font_template::FontTemplateData;
+use servo_net::resource_task::{ResourceTask, load_whole_resource};
+use url::Url;
+
+/// A list of font templates that make up a given font family.
+struct FontFamily {
+    templates: Vec<FontTemplate>,
+}
+
+impl FontFamily {
+    fn new() -> FontFamily {
+        FontFamily {
+            templates: vec!(),
+        }
+    }
+
+    /// Find a font in this family that matches a given desriptor.
+    fn find_font_for_style<'a>(&'a mut self, desc: &FontTemplateDescriptor, fctx: &FontContextHandle)
+                               -> Option<Arc<FontTemplateData>> {
+        // TODO(Issue #189): optimize lookup for
+        // regular/bold/italic/bolditalic with fixed offsets and a
+        // static decision table for fallback between these values.
+
+        // TODO(Issue #190): if not in the fast path above, do
+        // expensive matching of weights, etc.
+        for template in self.templates.mut_iter() {
+            let maybe_template = template.get_if_matches(fctx, desc);
+            if maybe_template.is_some() {
+                return maybe_template;
+            }
+        }
+
+        // If a request is made for a font family that exists,
+        // pick the first valid font in the family if we failed
+        // to find an exact match for the descriptor.
+        for template in self.templates.mut_iter() {
+            let maybe_template = template.get();
+            if maybe_template.is_some() {
+                return maybe_template;
+            }
+        }
+
+        None
+    }
+
+    fn add_template(&mut self, identifier: &str, maybe_data: Option<Vec<u8>>) {
+        for template in self.templates.iter() {
+            if template.identifier() == identifier {
+                return;
+            }
+        }
+
+        let template = FontTemplate::new(identifier, maybe_data);
+        self.templates.push(template);
+    }
+}
+
+/// Commands that the FontContext sends to the font cache task.
+pub enum Command {
+    GetFontTemplate(String, FontTemplateDescriptor, Sender<Reply>),
+    AddWebFont(String, Url, Sender<()>),
+    Exit(Sender<()>),
+}
+
+/// Reply messages sent from the font cache task to the FontContext caller.
+pub enum Reply {
+    GetFontTemplateReply(Arc<FontTemplateData>),
+}
+
+/// The font cache task itself. It maintains a list of reference counted
+/// font templates that are currently in use.
+struct FontCache {
+    port: Receiver<Command>,
+    generic_fonts: HashMap<String, String>,
+    local_families: HashMap<String, FontFamily>,
+    web_families: HashMap<String, FontFamily>,
+    font_context: FontContextHandle,
+    resource_task: ResourceTask,
+}
+
+impl FontCache {
+    fn run(&mut self) {
+        loop {
+            let msg = self.port.recv();
+
+            match msg {
+                GetFontTemplate(family, descriptor, result) => {
+                    let maybe_font_template = self.get_font_template(&family, &descriptor);
+                    let font_template = match maybe_font_template {
+                        Some(font_template) => font_template,
+                        None => self.get_last_resort_template(&descriptor),
+                    };
+
+                    result.send(GetFontTemplateReply(font_template));
+                }
+                AddWebFont(family_name, url, result) => {
+                    let maybe_resource = load_whole_resource(&self.resource_task, url.clone());
+                    match maybe_resource {
+                        Ok((_, bytes)) => {
+                            if !self.web_families.contains_key(&family_name) {
+                                let family = FontFamily::new();
+                                self.web_families.insert(family_name.clone(), family);
+                            }
+                            let family = self.web_families.get_mut(&family_name);
+                            family.add_template(format!("{}", url).as_slice(), Some(bytes));
+                        },
+                        Err(msg) => {
+                            fail!("{}: url={}", msg, url);
+                        }
+                    }
+                    result.send(());
+                }
+                Exit(result) => {
+                    result.send(());
+                    break;
+                }
+            }
+        }
+    }
+
+    fn refresh_local_families(&mut self) {
+        self.local_families.clear();
+        get_available_families(|family_name| {
+            if !self.local_families.contains_key(&family_name) {
+                let family = FontFamily::new();
+                self.local_families.insert(family_name, family);
+            }
+        });
+    }
+
+    fn transform_family(&self, family: &String) -> String {
+        match self.generic_fonts.find(family) {
+            None => family.to_string(),
+            Some(mapped_family) => (*mapped_family).clone()
+        }
+    }
+
+    fn find_font_in_local_family<'a>(&'a mut self, family_name: &String, desc: &FontTemplateDescriptor)
+                                -> Option<Arc<FontTemplateData>> {
+        // TODO(Issue #188): look up localized font family names if canonical name not found
+        // look up canonical name
+        if self.local_families.contains_key(family_name) {
+            debug!("FontList: Found font family with name={:s}", family_name.to_string());
+            let s = self.local_families.get_mut(family_name);
+
+            if s.templates.len() == 0 {
+                get_variations_for_family(family_name.as_slice(), |path| {
+                    s.add_template(path.as_slice(), None);
+                });
+            }
+
+            // TODO(Issue #192: handle generic font families, like 'serif' and 'sans-serif'.
+            // if such family exists, try to match style to a font
+            let result = s.find_font_for_style(desc, &self.font_context);
+            if result.is_some() {
+                return result;
+            }
+
+            None
+        } else {
+            debug!("FontList: Couldn't find font family with name={:s}", family_name.to_string());
+            None
+        }
+    }
+
+    fn find_font_in_web_family<'a>(&'a mut self, family_name: &String, desc: &FontTemplateDescriptor)
+                                -> Option<Arc<FontTemplateData>> {
+        if self.web_families.contains_key(family_name) {
+            let family = self.web_families.get_mut(family_name);
+            let maybe_font = family.find_font_for_style(desc, &self.font_context);
+            maybe_font
+        } else {
+            None
+        }
+    }
+
+    fn get_font_template(&mut self, family: &String, desc: &FontTemplateDescriptor) -> Option<Arc<FontTemplateData>> {
+        let transformed_family_name = self.transform_family(family);
+        let mut maybe_template = self.find_font_in_web_family(&transformed_family_name, desc);
+        if maybe_template.is_none() {
+            maybe_template = self.find_font_in_local_family(&transformed_family_name, desc);
+        }
+        maybe_template
+    }
+
+    fn get_last_resort_template(&mut self, desc: &FontTemplateDescriptor) -> Arc<FontTemplateData> {
+        let last_resort = get_last_resort_font_families();
+
+        for family in last_resort.iter() {
+            let maybe_font_in_family = self.find_font_in_local_family(family, desc);
+            if maybe_font_in_family.is_some() {
+                return maybe_font_in_family.unwrap();
+            }
+        }
+
+        fail!("Unable to find any fonts that match (do you have fallback fonts installed?)");
+    }
+}
+
+/// The public interface to the font cache task, used exclusively by
+/// the per-thread/task FontContext structures.
+#[deriving(Clone)]
+pub struct FontCacheTask {
+    chan: Sender<Command>,
+}
+
+impl FontCacheTask {
+    pub fn new(resource_task: ResourceTask) -> FontCacheTask {
+        let (chan, port) = channel();
+
+        spawn(proc() {
+            // TODO: Allow users to specify these.
+            let mut generic_fonts = HashMap::with_capacity(5);
+            generic_fonts.insert("serif".to_string(), "Times New Roman".to_string());
+            generic_fonts.insert("sans-serif".to_string(), "Arial".to_string());
+            generic_fonts.insert("cursive".to_string(), "Apple Chancery".to_string());
+            generic_fonts.insert("fantasy".to_string(), "Papyrus".to_string());
+            generic_fonts.insert("monospace".to_string(), "Menlo".to_string());
+
+            let mut cache = FontCache {
+                port: port,
+                generic_fonts: generic_fonts,
+                local_families: HashMap::new(),
+                web_families: HashMap::new(),
+                font_context: FontContextHandle::new(),
+                resource_task: resource_task,
+            };
+
+            cache.refresh_local_families();
+            cache.run();
+        });
+
+        FontCacheTask {
+            chan: chan,
+        }
+    }
+
+    pub fn get_font_template(&self, family: String, desc: FontTemplateDescriptor)
+                                                -> Arc<FontTemplateData> {
+
+        let (response_chan, response_port) = channel();
+        self.chan.send(GetFontTemplate(family, desc, response_chan));
+
+        let reply = response_port.recv();
+
+        match reply {
+            GetFontTemplateReply(data) => {
+                data
+            }
+        }
+    }
+
+    pub fn add_web_font(&self, family: String, url: Url) {
+        let (response_chan, response_port) = channel();
+        self.chan.send(AddWebFont(family, url, response_chan));
+        response_port.recv();
+    }
+
+    pub fn exit(&self) {
+        let (response_chan, response_port) = channel();
+        self.chan.send(Exit(response_chan));
+        response_port.recv();
+    }
+}

components/gfx/font_context.rs

@@ -0,0 +1,148 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+use font::{Font, FontGroup};
+use font::SpecifiedFontStyle;
+use platform::font_context::FontContextHandle;
+use style::computed_values::font_style;
+
+use font_cache_task::FontCacheTask;
+use font_template::FontTemplateDescriptor;
+use platform::font_template::FontTemplateData;
+use font::FontHandleMethods;
+use platform::font::FontHandle;
+use servo_util::cache::HashCache;
+
+use std::rc::{Rc, Weak};
+use std::cell::RefCell;
+use sync::Arc;
+
+use azure::AzFloat;
+use azure::azure_hl::BackendType;
+use azure::scaled_font::ScaledFont;
+
+#[cfg(target_os="linux")]
+#[cfg(target_os="android")]
+use azure::scaled_font::FontData;
+
+#[cfg(target_os="linux")]
+#[cfg(target_os="android")]
+fn create_scaled_font(backend: BackendType, template: &Arc<FontTemplateData>, pt_size: f64) -> ScaledFont {
+    ScaledFont::new(backend, FontData(&template.bytes), pt_size as AzFloat)
+}
+
+#[cfg(target_os="macos")]
+fn create_scaled_font(backend: BackendType, template: &Arc<FontTemplateData>, pt_size: f64) -> ScaledFont {
+    let cgfont = template.ctfont.get_ref().copy_to_CGFont();
+    ScaledFont::new(backend, &cgfont, pt_size as AzFloat)
+}
+
+/// A cached azure font (per render task) that
+/// can be shared by multiple text runs.
+struct RenderFontCacheEntry {
+    pt_size: f64,
+    identifier: String,
+    font: Rc<RefCell<ScaledFont>>,
+}
+
+/// The FontContext represents the per-thread/task state necessary for
+/// working with fonts. It is the public API used by the layout and
+/// render code. It talks directly to the font cache task where
+/// required.
+pub struct FontContext {
+    platform_handle: FontContextHandle,
+    font_cache_task: FontCacheTask,
+
+    /// Weak reference as the layout FontContext is persistent.
+    layout_font_cache: Vec<Weak<RefCell<Font>>>,
+
+    /// Strong reference as the render FontContext is (for now) recycled
+    /// per frame. TODO: Make this weak when incremental redraw is done.
+    render_font_cache: Vec<RenderFontCacheEntry>,
+}
+
+impl FontContext {
+    pub fn new(font_cache_task: FontCacheTask) -> FontContext {
+        let handle = FontContextHandle::new();
+        FontContext {
+            platform_handle: handle,
+            font_cache_task: font_cache_task,
+            layout_font_cache: vec!(),
+            render_font_cache: vec!(),
+        }
+    }
+
+    /// Create a font for use in layout calculations.
+    fn create_layout_font(&self, template: Arc<FontTemplateData>,
+                            descriptor: FontTemplateDescriptor, pt_size: f64) -> Font {
+
+        let handle: FontHandle = FontHandleMethods::new_from_template(&self.platform_handle, template, Some(pt_size)).unwrap();
+        let metrics = handle.get_metrics();
+
+        Font {
+            handle: handle,
+            shaper: None,
+            descriptor: descriptor,
+            pt_size: pt_size,
+            metrics: metrics,
+            shape_cache: HashCache::new(),
+            glyph_advance_cache: HashCache::new(),
+        }
+    }
+
+    /// Create a group of fonts for use in layout calculations. May return
+    /// a cached font if this font instance has already been used by
+    /// this context.
+    pub fn get_layout_font_group_for_style(&mut self, style: &SpecifiedFontStyle) -> FontGroup {
+        // Remove all weak pointers that have been dropped.
+        self.layout_font_cache.retain(|maybe_font| {
+            maybe_font.upgrade().is_some()
+        });
+
+        let mut fonts: Vec<Rc<RefCell<Font>>> = vec!();
+
+        for family in style.families.iter() {
+            let desc = FontTemplateDescriptor::new(style.weight, style.style == font_style::italic);
+
+            // GWTODO: Check on real pages if this is faster as Vec() or HashMap().
+            let mut cache_hit = false;
+            for maybe_cached_font in self.layout_font_cache.iter() {
+                let cached_font = maybe_cached_font.upgrade().unwrap();
+                if cached_font.borrow().descriptor == desc {
+                    fonts.push(cached_font.clone());
+                    cache_hit = true;
+                    break;
+                }
+            }
+
+            if !cache_hit {
+                let font_template = self.font_cache_task.get_font_template(family.clone(), desc.clone());
+                let layout_font = Rc::new(RefCell::new(self.create_layout_font(font_template, desc.clone(), style.pt_size)));
+                self.layout_font_cache.push(layout_font.downgrade());
+                fonts.push(layout_font);
+            }
+        }
+
+        FontGroup::new(fonts)
+    }
+
+    /// Create a render font for use with azure. May return a cached
+    /// reference if already used by this font context.
+    pub fn get_render_font_from_template(&mut self, template: &Arc<FontTemplateData>, pt_size: f64, backend: BackendType) -> Rc<RefCell<ScaledFont>> {
+        for cached_font in self.render_font_cache.iter() {
+            if cached_font.pt_size == pt_size &&
+               cached_font.identifier == template.identifier {
+                return cached_font.font.clone();
+            }
+        }
+
+        let render_font = Rc::new(RefCell::new(create_scaled_font(backend, template, pt_size)));
+        self.render_font_cache.push(RenderFontCacheEntry{
+            font: render_font.clone(),
+            pt_size: pt_size,
+            identifier: template.identifier.clone(),
+        });
+        render_font
+    }
+}

components/gfx/font_template.rs

@@ -0,0 +1,157 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+use style::computed_values::font_weight;
+use platform::font_context::FontContextHandle;
+use platform::font::FontHandle;
+use platform::font_template::FontTemplateData;
+
+use sync::{Arc, Weak};
+use font::FontHandleMethods;
+
+/// Describes how to select a font from a given family.
+/// This is very basic at the moment and needs to be
+/// expanded or refactored when we support more of the
+/// font styling parameters.
+#[deriving(Clone)]
+pub struct FontTemplateDescriptor {
+    pub weight: font_weight::T,
+    pub italic: bool,
+}
+
+impl FontTemplateDescriptor {
+    pub fn new(weight: font_weight::T, italic: bool) -> FontTemplateDescriptor {
+        FontTemplateDescriptor {
+            weight: weight,
+            italic: italic,
+        }
+    }
+}
+
+impl PartialEq for FontTemplateDescriptor {
+    fn eq(&self, other: &FontTemplateDescriptor) -> bool {
+        self.weight.is_bold() == other.weight.is_bold() &&
+        self.italic == other.italic
+    }
+}
+
+/// This describes all the information needed to create
+/// font instance handles. It contains a unique
+/// FontTemplateData structure that is platform specific.
+pub struct FontTemplate {
+    identifier: String,
+    descriptor: Option<FontTemplateDescriptor>,
+    weak_ref: Option<Weak<FontTemplateData>>,
+    strong_ref: Option<Arc<FontTemplateData>>,      // GWTODO: Add code path to unset the strong_ref for web fonts!
+    is_valid: bool,
+}
+
+/// Holds all of the template information for a font that
+/// is common, regardless of the number of instances of
+/// this font handle per thread.
+impl FontTemplate {
+    pub fn new(identifier: &str, maybe_bytes: Option<Vec<u8>>) -> FontTemplate {
+        let maybe_data = match maybe_bytes {
+            Some(_) => Some(FontTemplateData::new(identifier, maybe_bytes)),
+            None => None,
+        };
+
+        let maybe_strong_ref = match maybe_data {
+            Some(data) => Some(Arc::new(data)),
+            None => None,
+        };
+
+        let maybe_weak_ref = match maybe_strong_ref {
+            Some(ref strong_ref) => Some(strong_ref.downgrade()),
+            None => None,
+        };
+
+        FontTemplate {
+            identifier: identifier.to_string(),
+            descriptor: None,
+            weak_ref: maybe_weak_ref,
+            strong_ref: maybe_strong_ref,
+            is_valid: true,
+        }
+    }
+
+    pub fn identifier<'a>(&'a self) -> &'a str {
+        self.identifier.as_slice()
+    }
+
+    /// Get the data for creating a font if it matches a given descriptor.
+    pub fn get_if_matches(&mut self, fctx: &FontContextHandle,
+                            requested_desc: &FontTemplateDescriptor) -> Option<Arc<FontTemplateData>> {
+        // The font template data can be unloaded when nothing is referencing
+        // it (via the Weak reference to the Arc above). However, if we have
+        // already loaded a font, store the style information about it separately,
+        // so that we can do font matching against it again in the future
+        // without having to reload the font (unless it is an actual match).
+        match self.descriptor {
+            Some(actual_desc) => {
+                if *requested_desc == actual_desc {
+                    Some(self.get_data())
+                } else {
+                    None
+                }
+            },
+            None => {
+                if self.is_valid {
+                    let data = self.get_data();
+                    let handle: Result<FontHandle, ()> = FontHandleMethods::new_from_template(fctx, data.clone(), None);
+                    match handle {
+                        Ok(handle) => {
+                            let actual_desc = FontTemplateDescriptor::new(handle.boldness(),
+                                                handle.is_italic());
+                            let desc_match = actual_desc == *requested_desc;
+
+                            self.descriptor = Some(actual_desc);
+                            self.is_valid = true;
+                            if desc_match {
+                                Some(data)
+                            } else {
+                                None
+                            }
+                        }
+                        Err(()) => {
+                            self.is_valid = false;
+                            debug!("Unable to create a font from template {}", self.identifier);
+                            None
+                        }
+                    }
+                } else {
+                    None
+                }
+            }
+        }
+    }
+
+    /// Get the data for creating a font.
+    pub fn get(&mut self) -> Option<Arc<FontTemplateData>> {
+        match self.is_valid {
+            true => Some(self.get_data()),
+            false => None
+        }
+    }
+
+    /// Get the font template data. If any strong references still
+    /// exist, it will return a clone, otherwise it will load the
+    /// font data and store a weak reference to it internally.
+    pub fn get_data(&mut self) -> Arc<FontTemplateData> {
+        let maybe_data = match self.weak_ref {
+            Some(ref data) => data.upgrade(),
+            None => None,
+        };
+
+        match maybe_data {
+            Some(data) => data,
+            None => {
+                assert!(self.strong_ref.is_none());
+                let template_data = Arc::new(FontTemplateData::new(self.identifier.as_slice(), None));
+                self.weak_ref = Some(template_data.downgrade());
+                template_data
+            }
+        }
+    }
+}

components/gfx/lib.rs

@@ -0,0 +1,72 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#![feature(globs, macro_rules, phase, unsafe_destructor)]
+
+#![feature(phase)]
+#[phase(plugin, link)]
+extern crate log;
+
+extern crate debug;
+extern crate azure;
+extern crate collections;
+extern crate geom;
+extern crate layers;
+extern crate libc;
+extern crate native;
+extern crate rustrt;
+extern crate stb_image;
+extern crate png;
+extern crate serialize;
+#[phase(plugin)]
+extern crate servo_macros = "macros";
+extern crate servo_net = "net";
+#[phase(plugin, link)]
+extern crate servo_util = "util";
+extern crate servo_msg = "msg";
+extern crate style;
+extern crate sync;
+extern crate url;
+
+// Eventually we would like the shaper to be pluggable, as many operating systems have their own
+// shapers. For now, however, this is a hard dependency.
+extern crate harfbuzz;
+
+// Linux and Android-specific library dependencies
+#[cfg(target_os="linux")] #[cfg(target_os="android")] extern crate fontconfig;
+#[cfg(target_os="linux")] #[cfg(target_os="android")] extern crate freetype;
+
+// Mac OS-specific library dependencies
+#[cfg(target_os="macos")] extern crate core_foundation;
+#[cfg(target_os="macos")] extern crate core_graphics;
+#[cfg(target_os="macos")] extern crate core_text;
+
+pub use render_context::RenderContext;
+
+// Private rendering modules
+mod render_context;
+
+// Rendering
+pub mod color;
+#[path="display_list/mod.rs"]
+pub mod display_list;
+pub mod render_task;
+
+// Fonts
+pub mod font;
+pub mod font_context;
+pub mod font_cache_task;
+pub mod font_template;
+
+// Misc.
+mod buffer_map;
+
+// Platform-specific implementations.
+#[path="platform/mod.rs"]
+pub mod platform;
+
+// Text
+#[path = "text/mod.rs"]
+pub mod text;
+

components/gfx/platform/freetype/font.rs

@@ -0,0 +1,297 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+extern crate freetype;
+
+use font::{FontHandleMethods, FontMetrics, FontTableMethods};
+use font::{FontTableTag, FractionalPixel};
+use servo_util::geometry::Au;
+use servo_util::geometry;
+use platform::font_context::FontContextHandle;
+use text::glyph::GlyphId;
+use text::util::{float_to_fixed, fixed_to_float};
+use style::computed_values::font_weight;
+use platform::font_template::FontTemplateData;
+
+use freetype::freetype::{FT_Get_Char_Index, FT_Get_Postscript_Name};
+use freetype::freetype::{FT_Load_Glyph, FT_Set_Char_Size};
+use freetype::freetype::{FT_Get_Kerning, FT_Get_Sfnt_Table};
+use freetype::freetype::{FT_New_Memory_Face, FT_Done_Face};
+use freetype::freetype::{FTErrorMethods, FT_F26Dot6, FT_Face, FT_FaceRec};
+use freetype::freetype::{FT_GlyphSlot, FT_Library, FT_Long, FT_ULong};
+use freetype::freetype::{FT_KERNING_DEFAULT, FT_STYLE_FLAG_ITALIC, FT_STYLE_FLAG_BOLD};
+use freetype::freetype::{FT_SizeRec, FT_UInt, FT_Size_Metrics, struct_FT_Vector_};
+use freetype::freetype::{ft_sfnt_os2};
+use freetype::tt_os2::TT_OS2;
+
+use std::mem;
+use std::ptr;
+use std::string;
+
+use sync::Arc;
+
+fn float_to_fixed_ft(f: f64) -> i32 {
+    float_to_fixed(6, f)
+}
+
+fn fixed_to_float_ft(f: i32) -> f64 {
+    fixed_to_float(6, f)
+}
+
+pub struct FontTable;
+
+impl FontTableMethods for FontTable {
+    fn with_buffer(&self, _blk: |*const u8, uint|) {
+        fail!()
+    }
+}
+
+pub struct FontHandle {
+    // The font binary. This must stay valid for the lifetime of the font,
+    // if the font is created using FT_Memory_Face.
+    pub font_data: Arc<FontTemplateData>,
+    pub face: FT_Face,
+    pub handle: FontContextHandle
+}
+
+#[unsafe_destructor]
+impl Drop for FontHandle {
+    fn drop(&mut self) {
+        assert!(self.face.is_not_null());
+        unsafe {
+            if !FT_Done_Face(self.face).succeeded() {
+                fail!("FT_Done_Face failed");
+            }
+        }
+    }
+}
+
+impl FontHandleMethods for FontHandle {
+    fn new_from_template(fctx: &FontContextHandle,
+                       template: Arc<FontTemplateData>,
+                       pt_size: Option<f64>)
+                        -> Result<FontHandle, ()> {
+        let ft_ctx: FT_Library = fctx.ctx.ctx;
+        if ft_ctx.is_null() { return Err(()); }
+
+        let bytes = &template.deref().bytes;
+        let face_result = create_face_from_buffer(ft_ctx, bytes.as_ptr(), bytes.len(), pt_size);
+
+        // TODO: this could be more simply written as result::chain
+        // and moving buf into the struct ctor, but cant' move out of
+        // captured binding.
+        return match face_result {
+            Ok(face) => {
+              let handle = FontHandle {
+                  face: face,
+                  font_data: template.clone(),
+                  handle: fctx.clone()
+              };
+              Ok(handle)
+            }
+            Err(()) => Err(())
+        };
+
+        fn create_face_from_buffer(lib: FT_Library, cbuf: *const u8, cbuflen: uint, pt_size: Option<f64>)
+                                   -> Result<FT_Face, ()> {
+            unsafe {
+                let mut face: FT_Face = ptr::mut_null();
+                let face_index = 0 as FT_Long;
+                let result = FT_New_Memory_Face(lib, cbuf, cbuflen as FT_Long,
+                                                face_index, &mut face);
+
+                if !result.succeeded() || face.is_null() {
+                    return Err(());
+                }
+                match pt_size {
+                    Some(s) => {
+                        match FontHandle::set_char_size(face, s) {
+                            Ok(_) => Ok(face),
+                            Err(_) => Err(()),
+                        }
+                    }
+                    None => Ok(face),
+                }
+            }
+        }
+    }
+    fn get_template(&self) -> Arc<FontTemplateData> {
+        self.font_data.clone()
+    }
+    fn family_name(&self) -> String {
+        unsafe { string::raw::from_buf(&*(*self.face).family_name as *const i8 as *const u8) }
+    }
+    fn face_name(&self) -> String {
+        unsafe { string::raw::from_buf(&*FT_Get_Postscript_Name(self.face) as *const i8 as *const u8) }
+    }
+    fn is_italic(&self) -> bool {
+        unsafe { (*self.face).style_flags & FT_STYLE_FLAG_ITALIC != 0 }
+    }
+    fn boldness(&self) -> font_weight::T {
+        let default_weight = font_weight::Weight400;
+        if unsafe { (*self.face).style_flags & FT_STYLE_FLAG_BOLD == 0 } {
+            default_weight
+        } else {
+            unsafe {
+                let os2 = FT_Get_Sfnt_Table(self.face, ft_sfnt_os2) as *mut TT_OS2;
+                let valid = os2.is_not_null() && (*os2).version != 0xffff;
+                if valid {
+                    let weight =(*os2).usWeightClass;
+                    match weight {
+                        1 | 100..199 => font_weight::Weight100,
+                        2 | 200..299 => font_weight::Weight200,
+                        3 | 300..399 => font_weight::Weight300,
+                        4 | 400..499 => font_weight::Weight400,
+                        5 | 500..599 => font_weight::Weight500,
+                        6 | 600..699 => font_weight::Weight600,
+                        7 | 700..799 => font_weight::Weight700,
+                        8 | 800..899 => font_weight::Weight800,
+                        9 | 900..999 => font_weight::Weight900,
+                        _ => default_weight
+                    }
+                } else {
+                    default_weight
+                }
+            }
+        }
+    }
+
+    fn glyph_index(&self,
+                       codepoint: char) -> Option<GlyphId> {
+        assert!(self.face.is_not_null());
+        unsafe {
+            let idx = FT_Get_Char_Index(self.face, codepoint as FT_ULong);
+            return if idx != 0 as FT_UInt {
+                Some(idx as GlyphId)
+            } else {
+                debug!("Invalid codepoint: {}", codepoint);
+                None
+            };
+        }
+    }
+
+    fn glyph_h_kerning(&self, first_glyph: GlyphId, second_glyph: GlyphId)
+                        -> FractionalPixel {
+        assert!(self.face.is_not_null());
+        let mut delta = struct_FT_Vector_ { x: 0, y: 0 };
+        unsafe {
+            FT_Get_Kerning(self.face, first_glyph, second_glyph, FT_KERNING_DEFAULT, &mut delta);
+        }
+        fixed_to_float_ft(delta.x as i32)
+    }
+
+    fn glyph_h_advance(&self,
+                           glyph: GlyphId) -> Option<FractionalPixel> {
+        assert!(self.face.is_not_null());
+        unsafe {
+            let res =  FT_Load_Glyph(self.face, glyph as FT_UInt, 0);
+            if res.succeeded() {
+                let void_glyph = (*self.face).glyph;
+                let slot: FT_GlyphSlot = mem::transmute(void_glyph);
+                assert!(slot.is_not_null());
+                debug!("metrics: {:?}", (*slot).metrics);
+                let advance = (*slot).metrics.horiAdvance;
+                debug!("h_advance for {} is {}", glyph, advance);
+                let advance = advance as i32;
+                return Some(fixed_to_float_ft(advance) as FractionalPixel);
+            } else {
+                debug!("Unable to load glyph {}. reason: {}", glyph, res);
+                return None;
+            }
+        }
+    }
+
+    fn get_metrics(&self) -> FontMetrics {
+        /* TODO(Issue #76): complete me */
+        let face = self.get_face_rec();
+
+        let underline_size = self.font_units_to_au(face.underline_thickness as f64);
+        let underline_offset = self.font_units_to_au(face.underline_position as f64);
+        let em_size = self.font_units_to_au(face.units_per_EM as f64);
+        let ascent = self.font_units_to_au(face.ascender as f64);
+        let descent = self.font_units_to_au(face.descender as f64);
+        let max_advance = self.font_units_to_au(face.max_advance_width as f64);
+
+        // 'leading' is supposed to be the vertical distance between two baselines,
+        // reflected by the height attibute in freetype.  On OS X (w/ CTFont),
+        // leading represents the distance between the bottom of a line descent to
+        // the top of the next line's ascent or: (line_height - ascent - descent),
+        // see http://stackoverflow.com/a/5635981 for CTFont implementation.
+        // Convert using a formular similar to what CTFont returns for consistency.
+        let height = self.font_units_to_au(face.height as f64);
+        let leading = height - (ascent + descent);
+
+        let mut strikeout_size = geometry::from_pt(0.0);
+        let mut strikeout_offset = geometry::from_pt(0.0);
+        let mut x_height = geometry::from_pt(0.0);
+        unsafe {
+            let os2 = FT_Get_Sfnt_Table(face, ft_sfnt_os2) as *mut TT_OS2;
+            let valid = os2.is_not_null() && (*os2).version != 0xffff;
+            if valid {
+               strikeout_size = self.font_units_to_au((*os2).yStrikeoutSize as f64);
+               strikeout_offset = self.font_units_to_au((*os2).yStrikeoutPosition as f64);
+               x_height = self.font_units_to_au((*os2).sxHeight as f64);
+            }
+        }
+
+        let metrics = FontMetrics {
+            underline_size:   underline_size,
+            underline_offset: underline_offset,
+            strikeout_size:   strikeout_size,
+            strikeout_offset: strikeout_offset,
+            leading:          leading,
+            x_height:         x_height,
+            em_size:          em_size,
+            ascent:           ascent,
+            descent:          -descent, // linux font's seem to use the opposite sign from mac
+            max_advance:      max_advance,
+            line_gap:         height,
+        };
+
+        debug!("Font metrics (@{:f} pt): {:?}", geometry::to_pt(em_size), metrics);
+        return metrics;
+    }
+
+    fn get_table_for_tag(&self, _: FontTableTag) -> Option<FontTable> {
+        None
+    }
+}
+
+impl<'a> FontHandle {
+    fn set_char_size(face: FT_Face, pt_size: f64) -> Result<(), ()>{
+        let char_width = float_to_fixed_ft(pt_size) as FT_F26Dot6;
+        let char_height = float_to_fixed_ft(pt_size) as FT_F26Dot6;
+        let h_dpi = 72;
+        let v_dpi = 72;
+
+        unsafe {
+            let result = FT_Set_Char_Size(face, char_width, char_height, h_dpi, v_dpi);
+            if result.succeeded() { Ok(()) } else { Err(()) }
+        }
+    }
+
+    fn get_face_rec(&'a self) -> &'a mut FT_FaceRec {
+        unsafe {
+            &mut (*self.face)
+        }
+    }
+
+    fn font_units_to_au(&self, value: f64) -> Au {
+        let face = self.get_face_rec();
+
+        // face.size is a *c_void in the bindings, presumably to avoid
+        // recursive structural types
+        let size: &FT_SizeRec = unsafe { mem::transmute(&(*face.size)) };
+        let metrics: &FT_Size_Metrics = &(*size).metrics;
+
+        let em_size = face.units_per_EM as f64;
+        let x_scale = (metrics.x_ppem as f64) / em_size as f64;
+
+        // If this isn't true then we're scaling one of the axes wrong
+        assert!(metrics.x_ppem == metrics.y_ppem);
+
+        return geometry::from_frac_px(value * x_scale);
+    }
+}
+

components/gfx/platform/freetype/font_context.rs

@@ -0,0 +1,82 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+use freetype::freetype::FTErrorMethods;
+use freetype::freetype::FT_Add_Default_Modules;
+use freetype::freetype::FT_Done_FreeType;
+use freetype::freetype::FT_Library;
+use freetype::freetype::FT_Memory;
+use freetype::freetype::FT_New_Library;
+use freetype::freetype::struct_FT_MemoryRec_;
+
+use std::ptr;
+use std::rc::Rc;
+
+use libc;
+use libc::{c_void, c_long, size_t, malloc};
+use std::mem;
+
+extern fn ft_alloc(_mem: FT_Memory, size: c_long) -> *mut c_void {
+    unsafe {
+        let ptr = libc::malloc(size as size_t);
+        ptr as *mut c_void
+    }
+}
+
+extern fn ft_free(_mem: FT_Memory, block: *mut c_void) {
+    unsafe {
+        libc::free(block);
+    }
+}
+
+extern fn ft_realloc(_mem: FT_Memory, _cur_size: c_long, new_size: c_long, block: *mut c_void) -> *mut c_void {
+    unsafe {
+        let ptr = libc::realloc(block, new_size as size_t);
+        ptr as *mut c_void
+    }
+}
+
+#[deriving(Clone)]
+pub struct FreeTypeLibraryHandle {
+    pub ctx: FT_Library,
+}
+
+#[deriving(Clone)]
+pub struct FontContextHandle {
+    pub ctx: Rc<FreeTypeLibraryHandle>,
+}
+
+impl Drop for FreeTypeLibraryHandle {
+    fn drop(&mut self) {
+        assert!(self.ctx.is_not_null());
+        unsafe { FT_Done_FreeType(self.ctx) };
+    }
+}
+
+impl FontContextHandle {
+    pub fn new() -> FontContextHandle {
+        unsafe {
+
+            let ptr = libc::malloc(mem::size_of::<struct_FT_MemoryRec_>() as size_t);
+            let allocator: &mut struct_FT_MemoryRec_ = mem::transmute(ptr);
+            ptr::write(allocator, struct_FT_MemoryRec_ {
+                user: ptr::mut_null(),
+                alloc: ft_alloc,
+                free: ft_free,
+                realloc: ft_realloc,
+            });
+
+            let mut ctx: FT_Library = ptr::mut_null();
+
+            let result = FT_New_Library(ptr as FT_Memory, &mut ctx);
+            if !result.succeeded() { fail!("Unable to initialize FreeType library"); }
+
+            FT_Add_Default_Modules(ctx);
+
+            FontContextHandle {
+                ctx: Rc::new(FreeTypeLibraryHandle { ctx: ctx }),
+            }
+        }
+    }
+}

components/gfx/platform/freetype/font_list.rs

@@ -0,0 +1,115 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#![allow(uppercase_variables)]
+
+extern crate freetype;
+extern crate fontconfig;
+
+use fontconfig::fontconfig::{FcChar8, FcResultMatch, FcSetSystem};
+use fontconfig::fontconfig::{
+    FcConfigGetCurrent, FcConfigGetFonts, FcPatternGetString,
+    FcPatternDestroy, FcFontSetDestroy,
+    FcPatternCreate, FcPatternAddString,
+    FcFontSetList, FcObjectSetCreate, FcObjectSetDestroy,
+    FcObjectSetAdd, FcPatternGetInteger
+};
+
+use libc;
+use libc::c_int;
+use std::ptr;
+use std::string;
+
+pub fn get_available_families(callback: |String|) {
+    unsafe {
+        let config = FcConfigGetCurrent();
+        let fontSet = FcConfigGetFonts(config, FcSetSystem);
+        for i in range(0, (*fontSet).nfont as int) {
+            let font = (*fontSet).fonts.offset(i);
+            let mut family: *mut FcChar8 = ptr::mut_null();
+            let mut v: c_int = 0;
+            let mut FC_FAMILY_C = "family".to_c_str();
+            let FC_FAMILY = FC_FAMILY_C.as_mut_ptr();
+            while FcPatternGetString(*font, FC_FAMILY, v, &mut family) == FcResultMatch {
+                let family_name = string::raw::from_buf(family as *const i8 as *const u8);
+                callback(family_name);
+                v += 1;
+            }
+        }
+    }
+}
+
+pub fn get_variations_for_family(family_name: &str, callback: |String|) {
+    debug!("getting variations for {}", family_name);
+    unsafe {
+        let config = FcConfigGetCurrent();
+        let mut font_set = FcConfigGetFonts(config, FcSetSystem);
+        let font_set_array_ptr = &mut font_set;
+        let pattern = FcPatternCreate();
+        assert!(pattern.is_not_null());
+        let mut FC_FAMILY_C = "family".to_c_str();
+        let FC_FAMILY = FC_FAMILY_C.as_mut_ptr();
+        let mut family_name_c = family_name.to_c_str();
+        let family_name = family_name_c.as_mut_ptr();
+        let ok = FcPatternAddString(pattern, FC_FAMILY, family_name as *mut FcChar8);
+        assert!(ok != 0);
+
+        let object_set = FcObjectSetCreate();
+        assert!(object_set.is_not_null());
+
+        let mut FC_FILE_C = "file".to_c_str();
+        let FC_FILE = FC_FILE_C.as_mut_ptr();
+        FcObjectSetAdd(object_set, FC_FILE);
+        let mut FC_INDEX_C = "index".to_c_str();
+        let FC_INDEX = FC_INDEX_C.as_mut_ptr();
+        FcObjectSetAdd(object_set, FC_INDEX);
+
+        let matches = FcFontSetList(config, font_set_array_ptr, 1, pattern, object_set);
+
+        debug!("found {} variations", (*matches).nfont);
+
+        for i in range(0, (*matches).nfont as int) {
+            let font = (*matches).fonts.offset(i);
+            let mut FC_FILE_C = "file".to_c_str();
+            let FC_FILE = FC_FILE_C.as_mut_ptr();
+            let mut file: *mut FcChar8 = ptr::mut_null();
+            let file = if FcPatternGetString(*font, FC_FILE, 0, &mut file) == FcResultMatch {
+                string::raw::from_buf(file as *const i8 as *const u8)
+            } else {
+                fail!();
+            };
+            let mut FC_INDEX_C = "index".to_c_str();
+            let FC_INDEX = FC_INDEX_C.as_mut_ptr();
+            let mut index: libc::c_int = 0;
+            let index = if FcPatternGetInteger(*font, FC_INDEX, 0, &mut index) == FcResultMatch {
+                index
+            } else {
+                fail!();
+            };
+
+            debug!("variation file: {}", file);
+            debug!("variation index: {}", index);
+
+            callback(file);
+        }
+
+        FcFontSetDestroy(matches);
+        FcPatternDestroy(pattern);
+        FcObjectSetDestroy(object_set);
+    }
+}
+
+#[cfg(target_os="linux")]
+pub fn get_last_resort_font_families() -> Vec<String> {
+    vec!(
+        "Fira Sans".to_string(),
+        "DejaVu Sans".to_string(),
+        "Arial".to_string()
+    )
+}
+
+#[cfg(target_os="android")]
+pub fn get_last_resort_font_families() -> Vec<String> {
+    vec!("Roboto".to_string())
+}

components/gfx/platform/freetype/font_template.rs

@@ -0,0 +1,35 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+use std::io;
+use std::io::File;
+
+/// Platform specific font representation for Linux.
+/// The identifier is an absolute path, and the bytes
+/// field is the loaded data that can be passed to
+/// freetype and azure directly.
+pub struct FontTemplateData {
+    pub bytes: Vec<u8>,
+    pub identifier: String,
+}
+
+impl FontTemplateData {
+    pub fn new(identifier: &str, font_data: Option<Vec<u8>>) -> FontTemplateData {
+        let bytes = match font_data {
+            Some(bytes) => {
+                bytes
+            },
+            None => {
+                // TODO: Handle file load failure!
+                let mut file = File::open_mode(&Path::new(identifier), io::Open, io::Read).unwrap();
+                file.read_to_end().unwrap()
+            },
+        };
+
+        FontTemplateData {
+            bytes: bytes,
+            identifier: identifier.to_string(),
+        }
+    }
+}

components/gfx/platform/macos/font.rs

@@ -0,0 +1,185 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/// Implementation of Quartz (CoreGraphics) fonts.
+
+extern crate core_foundation;
+extern crate core_graphics;
+extern crate core_text;
+
+use font::{FontHandleMethods, FontMetrics, FontTableMethods};
+use font::FontTableTag;
+use font::FractionalPixel;
+use servo_util::geometry::{Au, px_to_pt};
+use servo_util::geometry;
+use platform::macos::font_context::FontContextHandle;
+use text::glyph::GlyphId;
+use style::computed_values::font_weight;
+use platform::font_template::FontTemplateData;
+
+use core_foundation::base::CFIndex;
+use core_foundation::data::CFData;
+use core_foundation::string::UniChar;
+use core_graphics::font::CGGlyph;
+use core_graphics::geometry::CGRect;
+use core_text::font::CTFont;
+use core_text::font_descriptor::{SymbolicTraitAccessors, TraitAccessors};
+use core_text::font_descriptor::{kCTFontDefaultOrientation};
+
+use std::ptr;
+use sync::Arc;
+
+pub struct FontTable {
+    data: CFData,
+}
+
+// Noncopyable.
+impl Drop for FontTable {
+    fn drop(&mut self) {}
+}
+
+impl FontTable {
+    pub fn wrap(data: CFData) -> FontTable {
+        FontTable { data: data }
+    }
+}
+
+impl FontTableMethods for FontTable {
+    fn with_buffer(&self, blk: |*const u8, uint|) {
+        blk(self.data.bytes().as_ptr(), self.data.len() as uint);
+    }
+}
+
+pub struct FontHandle {
+    pub font_data: Arc<FontTemplateData>,
+    pub ctfont: CTFont,
+}
+
+impl FontHandleMethods for FontHandle {
+    fn new_from_template(_fctx: &FontContextHandle,
+                       template: Arc<FontTemplateData>,
+                       pt_size: Option<f64>)
+                        -> Result<FontHandle, ()> {
+        let size = match pt_size {
+            Some(s) => s,
+            None => 0.0
+        };
+        match template.ctfont {
+            Some(ref ctfont) => {
+                Ok(FontHandle {
+                    font_data: template.clone(),
+                    ctfont: ctfont.clone_with_font_size(size),
+                })
+            }
+            None => {
+                Err(())
+            }
+        }
+    }
+
+    fn get_template(&self) -> Arc<FontTemplateData> {
+        self.font_data.clone()
+    }
+
+    fn family_name(&self) -> String {
+        self.ctfont.family_name()
+    }
+
+    fn face_name(&self) -> String {
+        self.ctfont.face_name()
+    }
+
+    fn is_italic(&self) -> bool {
+        self.ctfont.symbolic_traits().is_italic()
+    }
+
+    fn boldness(&self) -> font_weight::T {
+        // -1.0 to 1.0
+        let normalized = self.ctfont.all_traits().normalized_weight();
+        // 0.0 to 9.0
+        let normalized = (normalized + 1.0) / 2.0 * 9.0;
+        if normalized < 1.0 { return font_weight::Weight100; }
+        if normalized < 2.0 { return font_weight::Weight200; }
+        if normalized < 3.0 { return font_weight::Weight300; }
+        if normalized < 4.0 { return font_weight::Weight400; }
+        if normalized < 5.0 { return font_weight::Weight500; }
+        if normalized < 6.0 { return font_weight::Weight600; }
+        if normalized < 7.0 { return font_weight::Weight700; }
+        if normalized < 8.0 { return font_weight::Weight800; }
+        return font_weight::Weight900;
+    }
+
+    fn glyph_index(&self, codepoint: char) -> Option<GlyphId> {
+        let characters: [UniChar,  ..1] = [codepoint as UniChar];
+        let mut glyphs: [CGGlyph, ..1] = [0 as CGGlyph];
+        let count: CFIndex = 1;
+
+        let result = self.ctfont.get_glyphs_for_characters(&characters[0],
+                                                           &mut glyphs[0],
+                                                           count);
+
+        if !result {
+            // No glyph for this character
+            return None;
+        }
+
+        assert!(glyphs[0] != 0); // FIXME: error handling
+        return Some(glyphs[0] as GlyphId);
+    }
+
+    fn glyph_h_kerning(&self, _first_glyph: GlyphId, _second_glyph: GlyphId)
+                        -> FractionalPixel {
+        // TODO: Implement on mac
+        0.0
+    }
+
+    fn glyph_h_advance(&self, glyph: GlyphId) -> Option<FractionalPixel> {
+        let glyphs = [glyph as CGGlyph];
+        let advance = self.ctfont.get_advances_for_glyphs(kCTFontDefaultOrientation,
+                                                          &glyphs[0],
+                                                          ptr::mut_null(),
+                                                          1);
+        Some(advance as FractionalPixel)
+    }
+
+    fn get_metrics(&self) -> FontMetrics {
+        let bounding_rect: CGRect = self.ctfont.bounding_box();
+        let ascent = self.ctfont.ascent() as f64;
+        let descent = self.ctfont.descent() as f64;
+        let em_size = Au::from_frac_px(self.ctfont.pt_size() as f64);
+        let leading = self.ctfont.leading() as f64;
+
+        let scale = px_to_pt(self.ctfont.pt_size() as f64) / (ascent + descent);
+        let line_gap = (ascent + descent + leading + 0.5).floor();
+
+        let metrics =  FontMetrics {
+            underline_size:   Au::from_pt(self.ctfont.underline_thickness() as f64),
+            // TODO(Issue #201): underline metrics are not reliable. Have to pull out of font table
+            // directly.
+            //
+            // see also: https://bugs.webkit.org/show_bug.cgi?id=16768
+            // see also: https://bugreports.qt-project.org/browse/QTBUG-13364
+            underline_offset: Au::from_pt(self.ctfont.underline_position() as f64),
+            strikeout_size:   geometry::from_pt(0.0), // FIXME(Issue #942)
+            strikeout_offset: geometry::from_pt(0.0), // FIXME(Issue #942)
+            leading:          Au::from_pt(leading),
+            x_height:         Au::from_pt(self.ctfont.x_height() as f64),
+            em_size:          em_size,
+            ascent:           Au::from_pt(ascent * scale),
+            descent:          Au::from_pt(descent * scale),
+            max_advance:      Au::from_pt(bounding_rect.size.width as f64),
+            line_gap:         Au::from_frac_px(line_gap),
+        };
+        debug!("Font metrics (@{:f} pt): {:?}", self.ctfont.pt_size() as f64, metrics);
+        return metrics;
+    }
+
+    fn get_table_for_tag(&self, tag: FontTableTag) -> Option<FontTable> {
+        let result: Option<CFData> = self.ctfont.get_font_table(tag);
+        result.and_then(|data| {
+            Some(FontTable::wrap(data))
+        })
+    }
+}
+

components/gfx/platform/macos/font_context.rs

@@ -0,0 +1,16 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#[deriving(Clone)]
+pub struct FontContextHandle {
+    ctx: ()
+}
+
+#[deriving(Clone)]
+impl FontContextHandle {
+    // this is a placeholder until NSFontManager or whatever is bound in here.
+    pub fn new() -> FontContextHandle {
+        FontContextHandle { ctx: () }
+    }
+}

components/gfx/platform/macos/font_list.rs

@@ -0,0 +1,37 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+use core_foundation::base::TCFType;
+use core_foundation::string::{CFString, CFStringRef};
+use core_text::font_descriptor::{CTFontDescriptor, CTFontDescriptorRef};
+use core_text;
+use std::mem;
+
+pub fn get_available_families(callback: |String|) {
+    let family_names = core_text::font_collection::get_family_names();
+    for strref in family_names.iter() {
+        let family_name_ref: CFStringRef = unsafe { mem::transmute(strref) };
+        let family_name_cf: CFString = unsafe { TCFType::wrap_under_get_rule(family_name_ref) };
+        let family_name = family_name_cf.to_string();
+        callback(family_name);
+    }
+}
+
+pub fn get_variations_for_family(family_name: &str, callback: |String|) {
+    debug!("Looking for faces of family: {:s}", family_name);
+
+    let family_collection =
+        core_text::font_collection::create_for_family(family_name.as_slice());
+    let family_descriptors = family_collection.get_descriptors();
+    for descref in family_descriptors.iter() {
+        let descref: CTFontDescriptorRef = unsafe { mem::transmute(descref) };
+        let desc: CTFontDescriptor = unsafe { TCFType::wrap_under_get_rule(descref) };
+        let postscript_name = desc.font_name();
+        callback(postscript_name);
+    }
+}
+
+pub fn get_last_resort_font_families() -> Vec<String> {
+    vec!("Arial Unicode MS".to_string(), "Arial".to_string())
+}

components/gfx/platform/macos/font_template.rs

@@ -0,0 +1,40 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+use core_graphics::data_provider::CGDataProvider;
+use core_graphics::font::CGFont;
+use core_text::font::CTFont;
+use core_text;
+
+/// Platform specific font representation for mac.
+/// The identifier is a PostScript font name. The
+/// CTFont object is cached here for use by the
+/// render functions that create CGFont references.
+pub struct FontTemplateData {
+    pub ctfont: Option<CTFont>,
+    pub identifier: String,
+}
+
+impl FontTemplateData {
+    pub fn new(identifier: &str, font_data: Option<Vec<u8>>) -> FontTemplateData {
+        let ctfont = match font_data {
+            Some(bytes) => {
+                let fontprov = CGDataProvider::from_buffer(bytes.as_slice());
+                let cgfont_result = CGFont::from_data_provider(fontprov);
+                match cgfont_result {
+                    Ok(cgfont) => Some(core_text::font::new_from_CGFont(&cgfont, 0.0)),
+                    Err(_) => None
+                }
+            },
+            None => {
+                Some(core_text::font::new_from_name(identifier.as_slice(), 0.0).unwrap())
+            }
+        };
+
+        FontTemplateData {
+            ctfont: ctfont,
+            identifier: identifier.to_string(),
+        }
+    }
+}

components/gfx/platform/mod.rs

@@ -0,0 +1,27 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#[cfg(target_os="linux")]
+#[cfg(target_os="android")]
+pub use platform::freetype::{font, font_context, font_list, font_template};
+
+#[cfg(target_os="macos")]
+pub use platform::macos::{font, font_context, font_list, font_template};
+
+#[cfg(target_os="linux")]
+#[cfg(target_os="android")]
+pub mod freetype {
+    pub mod font;
+    pub mod font_context;
+    pub mod font_list;
+    pub mod font_template;
+}
+
+#[cfg(target_os="macos")]
+pub mod macos {
+    pub mod font;
+    pub mod font_context;
+    pub mod font_list;
+    pub mod font_template;
+}

components/gfx/render_context.rs

@@ -0,0 +1,419 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+use font_context::FontContext;
+use style::computed_values::border_style;
+
+use azure::azure_hl::{B8G8R8A8, A8, Color, ColorPattern, DrawOptions, DrawSurfaceOptions, DrawTarget};
+use azure::azure_hl::{Linear, SourceOp, StrokeOptions};
+use azure::AZ_CAP_BUTT;
+use azure::AzFloat;
+use geom::point::Point2D;
+use geom::rect::Rect;
+use geom::size::Size2D;
+use geom::side_offsets::SideOffsets2D;
+use libc::types::common::c99::uint16_t;
+use libc::size_t;
+use png::{RGB8, RGBA8, K8, KA8};
+use servo_net::image::base::Image;
+use servo_util::geometry::Au;
+use servo_util::opts::Opts;
+use sync::Arc;
+
+pub struct RenderContext<'a> {
+    pub draw_target: &'a DrawTarget,
+    pub font_ctx: &'a mut Box<FontContext>,
+    pub opts: &'a Opts,
+    /// The rectangle that this context encompasses in page coordinates.
+    pub page_rect: Rect<f32>,
+    /// The rectangle that this context encompasses in screen coordinates (pixels).
+    pub screen_rect: Rect<uint>,
+}
+
+enum Direction {
+    Top,
+    Left,
+    Right,
+    Bottom
+}
+
+enum DashSize {
+    DottedBorder = 1,
+    DashedBorder = 3
+}
+
+impl<'a> RenderContext<'a>  {
+    pub fn get_draw_target(&self) -> &'a DrawTarget {
+        self.draw_target
+    }
+
+    pub fn draw_solid_color(&self, bounds: &Rect<Au>, color: Color) {
+        self.draw_target.make_current();
+        self.draw_target.fill_rect(&bounds.to_azure_rect(), &ColorPattern::new(color), None);
+    }
+
+    pub fn draw_border(&self,
+                       bounds: &Rect<Au>,
+                       border: SideOffsets2D<Au>,
+                       color: SideOffsets2D<Color>,
+                       style: SideOffsets2D<border_style::T>) {
+        let border = border.to_float_px();
+        self.draw_target.make_current();
+
+        self.draw_border_segment(Top, bounds, border, color, style);
+        self.draw_border_segment(Right, bounds, border, color, style);
+        self.draw_border_segment(Bottom, bounds, border, color, style);
+        self.draw_border_segment(Left, bounds, border, color, style);
+    }
+
+    pub fn draw_line(&self,
+                     bounds: &Rect<Au>,
+                     color: Color,
+                     style: border_style::T) {
+        self.draw_target.make_current();
+
+        self.draw_line_segment(bounds, color, style);
+    }
+
+    pub fn draw_push_clip(&self, bounds: &Rect<Au>) {
+        let rect = bounds.to_azure_rect();
+        let path_builder = self.draw_target.create_path_builder();
+
+        let left_top = Point2D(rect.origin.x, rect.origin.y);
+        let right_top = Point2D(rect.origin.x + rect.size.width, rect.origin.y);
+        let left_bottom = Point2D(rect.origin.x, rect.origin.y + rect.size.height);
+        let right_bottom = Point2D(rect.origin.x + rect.size.width, rect.origin.y + rect.size.height);
+
+        path_builder.move_to(left_top);
+        path_builder.line_to(right_top);
+        path_builder.line_to(right_bottom);
+        path_builder.line_to(left_bottom);
+
+        let path = path_builder.finish();
+        self.draw_target.push_clip(&path);
+    }
+
+    pub fn draw_pop_clip(&self) {
+        self.draw_target.pop_clip();
+    }
+
+    pub fn draw_image(&self, bounds: Rect<Au>, image: Arc<Box<Image>>) {
+        let size = Size2D(image.width as i32, image.height as i32);
+        let (pixel_width, pixels, source_format) = match image.pixels {
+            RGBA8(ref pixels) => (4, pixels.as_slice(), B8G8R8A8),
+            K8(ref pixels) => (1, pixels.as_slice(), A8),
+            RGB8(_) => fail!("RGB8 color type not supported"),
+            KA8(_) => fail!("KA8 color type not supported"),
+        };
+        let stride = image.width * pixel_width;
+
+        self.draw_target.make_current();
+        let draw_target_ref = &self.draw_target;
+        let azure_surface = draw_target_ref.create_source_surface_from_data(pixels,
+                                                                            size,
+                                                                            stride as i32,
+                                                                            source_format);
+        let source_rect = Rect(Point2D(0u as AzFloat, 0u as AzFloat),
+                               Size2D(image.width as AzFloat, image.height as AzFloat));
+        let dest_rect = bounds.to_azure_rect();
+        let draw_surface_options = DrawSurfaceOptions::new(Linear, true);
+        let draw_options = DrawOptions::new(1.0f64 as AzFloat, 0);
+        draw_target_ref.draw_surface(azure_surface,
+                                     dest_rect,
+                                     source_rect,
+                                     draw_surface_options,
+                                     draw_options);
+    }
+
+    pub fn clear(&self) {
+        let pattern = ColorPattern::new(Color::new(0.0, 0.0, 0.0, 0.0));
+        let rect = Rect(Point2D(self.page_rect.origin.x as AzFloat,
+                                self.page_rect.origin.y as AzFloat),
+                        Size2D(self.screen_rect.size.width as AzFloat,
+                               self.screen_rect.size.height as AzFloat));
+        let mut draw_options = DrawOptions::new(1.0, 0);
+        draw_options.set_composition_op(SourceOp);
+        self.draw_target.make_current();
+        self.draw_target.fill_rect(&rect, &pattern, Some(&draw_options));
+    }
+
+    fn draw_border_segment(&self, direction: Direction, bounds: &Rect<Au>, border: SideOffsets2D<f32>, color: SideOffsets2D<Color>, style: SideOffsets2D<border_style::T>) {
+        let (style_select, color_select) = match direction {
+            Top => (style.top, color.top),
+            Left => (style.left, color.left),
+            Right => (style.right, color.right),
+            Bottom => (style.bottom, color.bottom)
+        };
+
+        match style_select{
+            border_style::none                         => {
+            }
+            border_style::hidden                       => {
+            }
+            //FIXME(sammykim): This doesn't work with dash_pattern and cap_style well. I referred firefox code.
+            border_style::dotted                       => {
+                self.draw_dashed_border_segment(direction, bounds, border, color_select, DottedBorder);
+            }
+            border_style::dashed                       => {
+                self.draw_dashed_border_segment(direction, bounds, border, color_select, DashedBorder);
+            }
+            border_style::solid                        => {
+                self.draw_solid_border_segment(direction,bounds,border,color_select);
+            }
+            border_style::double                       => {
+                self.draw_double_border_segment(direction, bounds, border, color_select);
+            }
+            border_style::groove | border_style::ridge => {
+                self.draw_groove_ridge_border_segment(direction, bounds, border, color_select, style_select);
+            }
+            border_style::inset | border_style::outset => {
+                self.draw_inset_outset_border_segment(direction, bounds, border, style_select, color_select);
+            }
+        }
+    }
+
+    fn draw_line_segment(&self, bounds: &Rect<Au>, color: Color, style: border_style::T) {
+        let border = SideOffsets2D::new_all_same(bounds.size.width).to_float_px();
+
+        match style{
+            border_style::none | border_style::hidden  => {}
+            border_style::dotted                       => {
+                self.draw_dashed_border_segment(Right, bounds, border, color, DottedBorder);
+            }
+            border_style::dashed                       => {
+                self.draw_dashed_border_segment(Right, bounds, border, color, DashedBorder);
+            }
+            border_style::solid                        => {
+                self.draw_solid_border_segment(Right,bounds,border,color);
+            }
+            border_style::double                       => {
+                self.draw_double_border_segment(Right, bounds, border, color);
+            }
+            border_style::groove | border_style::ridge => {
+                self.draw_groove_ridge_border_segment(Right, bounds, border, color, style);
+            }
+            border_style::inset | border_style::outset => {
+                self.draw_inset_outset_border_segment(Right, bounds, border, style, color);
+            }
+        }
+    }
+
+    fn draw_border_path(&self,
+                        bounds:    Rect<f32>,
+                        direction: Direction,
+                        border:    SideOffsets2D<f32>,
+                        color:     Color) {
+        let left_top     = bounds.origin;
+        let right_top    = left_top + Point2D(bounds.size.width, 0.0);
+        let left_bottom  = left_top + Point2D(0.0, bounds.size.height);
+        let right_bottom = left_top + Point2D(bounds.size.width, bounds.size.height);
+        let draw_opts    = DrawOptions::new(1.0, 0);
+        let path_builder = self.draw_target.create_path_builder();
+         match direction {
+             Top    => {
+                 path_builder.move_to(left_top);
+                 path_builder.line_to(right_top);
+                 path_builder.line_to(right_top + Point2D(-border.right, border.top));
+                 path_builder.line_to(left_top + Point2D(border.left, border.top));
+             }
+             Left   => {
+                 path_builder.move_to(left_top);
+                 path_builder.line_to(left_top + Point2D(border.left, border.top));
+                 path_builder.line_to(left_bottom + Point2D(border.left, -border.bottom));
+                 path_builder.line_to(left_bottom);
+             }
+             Right  => {
+                 path_builder.move_to(right_top);
+                 path_builder.line_to(right_bottom);
+                 path_builder.line_to(right_bottom + Point2D(-border.right, -border.bottom));
+                 path_builder.line_to(right_top + Point2D(-border.right, border.top));
+             }
+             Bottom => {
+                 path_builder.move_to(left_bottom);
+                 path_builder.line_to(left_bottom + Point2D(border.left, -border.bottom));
+                 path_builder.line_to(right_bottom + Point2D(-border.right, -border.bottom));
+                 path_builder.line_to(right_bottom);
+             }
+         }
+         let path = path_builder.finish();
+         self.draw_target.fill(&path, &ColorPattern::new(color), &draw_opts);
+
+     }
+
+    fn draw_dashed_border_segment(&self,
+                                  direction: Direction,
+                                  bounds:    &Rect<Au>,
+                                  border:    SideOffsets2D<f32>,
+                                  color:     Color,
+                                  dash_size: DashSize) {
+        let rect = bounds.to_azure_rect();
+        let draw_opts = DrawOptions::new(1u as AzFloat, 0 as uint16_t);
+        let mut stroke_opts = StrokeOptions::new(0u as AzFloat, 10u as AzFloat);
+        let mut dash: [AzFloat, ..2] = [0u as AzFloat, 0u as AzFloat];
+
+        stroke_opts.set_cap_style(AZ_CAP_BUTT as u8);
+
+        let border_width = match direction {
+            Top => border.top,
+            Left => border.left,
+            Right => border.right,
+            Bottom => border.bottom
+        };
+
+        stroke_opts.line_width = border_width;
+        dash[0] = border_width * (dash_size as int) as AzFloat;
+        dash[1] = border_width * (dash_size as int) as AzFloat;
+        stroke_opts.mDashPattern = dash.as_mut_ptr();
+        stroke_opts.mDashLength = dash.len() as size_t;
+
+        let (start, end)  = match direction {
+            Top => {
+                let y = rect.origin.y + border.top * 0.5;
+                let start = Point2D(rect.origin.x, y);
+                let end = Point2D(rect.origin.x + rect.size.width, y);
+                (start, end)
+            }
+            Left => {
+                let x = rect.origin.x + border.left * 0.5;
+                let start = Point2D(x, rect.origin.y + rect.size.height);
+                let end = Point2D(x, rect.origin.y + border.top);
+                (start, end)
+            }
+            Right => {
+                let x = rect.origin.x + rect.size.width - border.right * 0.5;
+                let start = Point2D(x, rect.origin.y);
+                let end = Point2D(x, rect.origin.y + rect.size.height);
+                (start, end)
+            }
+            Bottom => {
+                let y = rect.origin.y + rect.size.height - border.bottom * 0.5;
+                let start = Point2D(rect.origin.x + rect.size.width, y);
+                let end = Point2D(rect.origin.x + border.left, y);
+                (start, end)
+            }
+        };
+
+        self.draw_target.stroke_line(start,
+                                     end,
+                                     &ColorPattern::new(color),
+                                     &stroke_opts,
+                                     &draw_opts);
+    }
+
+    fn draw_solid_border_segment(&self, direction: Direction, bounds: &Rect<Au>, border: SideOffsets2D<f32>, color: Color) {
+        let rect = bounds.to_azure_rect();
+        self.draw_border_path(rect, direction, border, color);
+    }
+
+    fn get_scaled_bounds(&self,
+                         bounds:        &Rect<Au>,
+                         border:        SideOffsets2D<f32>,
+                         shrink_factor: f32) -> Rect<f32> {
+        let rect            = bounds.to_azure_rect();
+        let scaled_border   = SideOffsets2D::new(shrink_factor * border.top,
+                                                 shrink_factor * border.right,
+                                                 shrink_factor * border.bottom,
+                                                 shrink_factor * border.left);
+        let left_top        = Point2D(rect.origin.x, rect.origin.y);
+        let scaled_left_top = left_top + Point2D(scaled_border.left,
+                                                 scaled_border.top);
+        return Rect(scaled_left_top,
+                    Size2D(rect.size.width - 2.0 * scaled_border.right, rect.size.height - 2.0 * scaled_border.bottom));
+    }
+
+    fn scale_color(&self, color: Color, scale_factor: f32) -> Color {
+        return Color::new(color.r * scale_factor, color.g * scale_factor, color.b * scale_factor, color.a);
+    }
+
+    fn draw_double_border_segment(&self, direction: Direction, bounds: &Rect<Au>, border: SideOffsets2D<f32>, color: Color) {
+        let scaled_border       = SideOffsets2D::new((1.0/3.0) * border.top,
+                                                     (1.0/3.0) * border.right,
+                                                     (1.0/3.0) * border.bottom,
+                                                     (1.0/3.0) * border.left);
+        let inner_scaled_bounds = self.get_scaled_bounds(bounds, border, 2.0/3.0);
+        // draw the outer portion of the double border.
+        self.draw_solid_border_segment(direction, bounds, scaled_border, color);
+        // draw the inner portion of the double border.
+        self.draw_border_path(inner_scaled_bounds, direction, scaled_border, color);
+    }
+
+    fn draw_groove_ridge_border_segment(&self,
+                                        direction: Direction,
+                                        bounds:    &Rect<Au>,
+                                        border:    SideOffsets2D<f32>,
+                                        color:     Color,
+                                        style:     border_style::T) {
+        // original bounds as a Rect<f32>, with no scaling.
+        let original_bounds            = self.get_scaled_bounds(bounds, border, 0.0);
+        // shrink the bounds by 1/2 of the border, leaving the innermost 1/2 of the border
+        let inner_scaled_bounds        = self.get_scaled_bounds(bounds, border, 0.5);
+        let scaled_border              = SideOffsets2D::new(0.5 * border.top,
+                                                            0.5 * border.right,
+                                                            0.5 * border.bottom,
+                                                            0.5 * border.left);
+        let is_groove = match style {
+                border_style::groove =>  true,
+                border_style::ridge  =>  false,
+                _                    =>  fail!("invalid border style")
+        };
+        let darker_color               = self.scale_color(color, if is_groove { 1.0/3.0 } else { 2.0/3.0 });
+        let (outer_color, inner_color) = match (direction, is_groove) {
+            (Top, true)  | (Left, true)  | (Right, false) | (Bottom, false) => (darker_color, color),
+            (Top, false) | (Left, false) | (Right, true)  | (Bottom, true)  => (color, darker_color)
+        };
+        // outer portion of the border
+        self.draw_border_path(original_bounds, direction, scaled_border, outer_color);
+        // inner portion of the border
+        self.draw_border_path(inner_scaled_bounds, direction, scaled_border, inner_color);
+    }
+
+    fn draw_inset_outset_border_segment(&self,
+                                        direction: Direction,
+                                        bounds:    &Rect<Au>,
+                                        border:    SideOffsets2D<f32>,
+                                        style:     border_style::T,
+                                        color:     Color) {
+        let is_inset = match style {
+                border_style::inset  =>  true,
+                border_style::outset =>  false,
+                _                    =>  fail!("invalid border style")
+        };
+        // original bounds as a Rect<f32>
+        let original_bounds = self.get_scaled_bounds(bounds, border, 0.0);
+        // select and scale the color appropriately.
+        let scaled_color    = match direction {
+            Top             => self.scale_color(color, if is_inset { 2.0/3.0 } else { 1.0     }),
+            Left            => self.scale_color(color, if is_inset { 1.0/6.0 } else { 0.5     }),
+            Right | Bottom  => self.scale_color(color, if is_inset { 1.0     } else { 2.0/3.0 })
+        };
+        self.draw_border_path(original_bounds, direction, border, scaled_color);
+    }
+
+}
+
+trait ToAzureRect {
+    fn to_azure_rect(&self) -> Rect<AzFloat>;
+}
+
+impl ToAzureRect for Rect<Au> {
+    fn to_azure_rect(&self) -> Rect<AzFloat> {
+        Rect(Point2D(self.origin.x.to_nearest_px() as AzFloat,
+                     self.origin.y.to_nearest_px() as AzFloat),
+             Size2D(self.size.width.to_nearest_px() as AzFloat,
+                    self.size.height.to_nearest_px() as AzFloat))
+    }
+}
+
+trait ToSideOffsetsPx {
+    fn to_float_px(&self) -> SideOffsets2D<AzFloat>;
+}
+
+impl ToSideOffsetsPx for SideOffsets2D<Au> {
+    fn to_float_px(&self) -> SideOffsets2D<AzFloat> {
+        SideOffsets2D::new(self.top.to_nearest_px() as AzFloat,
+                           self.right.to_nearest_px() as AzFloat,
+                           self.bottom.to_nearest_px() as AzFloat,
+                           self.left.to_nearest_px() as AzFloat)
+    }
+}

components/gfx/render_task.rs

@@ -0,0 +1,443 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+//! The task that handles all rendering/painting.
+
+use buffer_map::BufferMap;
+use display_list::optimizer::DisplayListOptimizer;
+use display_list::DisplayList;
+use font_context::FontContext;
+use render_context::RenderContext;
+
+use azure::azure_hl::{B8G8R8A8, Color, DrawTarget, StolenGLResources};
+use azure::AzFloat;
+use geom::matrix2d::Matrix2D;
+use geom::rect::Rect;
+use geom::size::Size2D;
+use layers::platform::surface::{NativePaintingGraphicsContext, NativeSurface};
+use layers::platform::surface::{NativeSurfaceMethods};
+use layers::layers::{BufferRequest, LayerBuffer, LayerBufferSet};
+use layers;
+use servo_msg::compositor_msg::{Epoch, IdleRenderState, LayerId};
+use servo_msg::compositor_msg::{LayerMetadata, RenderListener, RenderingRenderState, ScrollPolicy};
+use servo_msg::constellation_msg::{ConstellationChan, Failure, FailureMsg, PipelineId};
+use servo_msg::constellation_msg::{RendererReadyMsg};
+use servo_msg::platform::surface::NativeSurfaceAzureMethods;
+use servo_util::geometry;
+use servo_util::opts::Opts;
+use servo_util::smallvec::{SmallVec, SmallVec1};
+use servo_util::task::spawn_named_with_send_on_failure;
+use servo_util::time::{TimeProfilerChan, profile};
+use servo_util::time;
+use std::comm::{Receiver, Sender, channel};
+use sync::Arc;
+use font_cache_task::FontCacheTask;
+
+/// Information about a layer that layout sends to the painting task.
+pub struct RenderLayer {
+    /// A per-pipeline ID describing this layer that should be stable across reflows.
+    pub id: LayerId,
+    /// The display list describing the contents of this layer.
+    pub display_list: Arc<DisplayList>,
+    /// The position of the layer in pixels.
+    pub position: Rect<uint>,
+    /// The color of the background in this layer. Used for unrendered content.
+    pub background_color: Color,
+    /// The scrolling policy of this layer.
+    pub scroll_policy: ScrollPolicy,
+}
+
+pub struct RenderRequest {
+    pub buffer_requests: Vec<BufferRequest>,
+    pub scale: f32,
+    pub layer_id: LayerId,
+    pub epoch: Epoch,
+}
+
+pub enum Msg {
+    RenderInitMsg(SmallVec1<RenderLayer>),
+    RenderMsg(Vec<RenderRequest>),
+    UnusedBufferMsg(Vec<Box<LayerBuffer>>),
+    PaintPermissionGranted,
+    PaintPermissionRevoked,
+    ExitMsg(Option<Sender<()>>),
+}
+
+#[deriving(Clone)]
+pub struct RenderChan(Sender<Msg>);
+
+impl RenderChan {
+    pub fn new() -> (Receiver<Msg>, RenderChan) {
+        let (chan, port) = channel();
+        (port, RenderChan(chan))
+    }
+
+    pub fn send(&self, msg: Msg) {
+        let &RenderChan(ref chan) = self;
+        assert!(chan.send_opt(msg).is_ok(), "RenderChan.send: render port closed")
+    }
+
+    pub fn send_opt(&self, msg: Msg) -> Result<(), Msg> {
+        let &RenderChan(ref chan) = self;
+        chan.send_opt(msg)
+    }
+}
+
+/// If we're using GPU rendering, this provides the metadata needed to create a GL context that
+/// is compatible with that of the main thread.
+pub enum GraphicsContext {
+    CpuGraphicsContext,
+    GpuGraphicsContext,
+}
+
+pub struct RenderTask<C> {
+    id: PipelineId,
+    port: Receiver<Msg>,
+    compositor: C,
+    constellation_chan: ConstellationChan,
+    font_ctx: Box<FontContext>,
+    opts: Opts,
+
+    /// A channel to the time profiler.
+    time_profiler_chan: TimeProfilerChan,
+
+    /// The graphics context to use.
+    graphics_context: GraphicsContext,
+
+    /// The native graphics context.
+    native_graphics_context: Option<NativePaintingGraphicsContext>,
+
+    /// The layers to be rendered.
+    render_layers: SmallVec1<RenderLayer>,
+
+    /// Permission to send paint messages to the compositor
+    paint_permission: bool,
+
+    /// A counter for epoch messages
+    epoch: Epoch,
+
+    /// A data structure to store unused LayerBuffers
+    buffer_map: BufferMap,
+}
+
+// If we implement this as a function, we get borrowck errors from borrowing
+// the whole RenderTask struct.
+macro_rules! native_graphics_context(
+    ($task:expr) => (
+        $task.native_graphics_context.as_ref().expect("Need a graphics context to do rendering")
+    )
+)
+
+fn initialize_layers<C:RenderListener>(
+                     compositor: &mut C,
+                     pipeline_id: PipelineId,
+                     epoch: Epoch,
+                     render_layers: &[RenderLayer]) {
+    let metadata = render_layers.iter().map(|render_layer| {
+        LayerMetadata {
+            id: render_layer.id,
+            position: render_layer.position,
+            background_color: render_layer.background_color,
+            scroll_policy: render_layer.scroll_policy,
+        }
+    }).collect();
+    compositor.initialize_layers_for_pipeline(pipeline_id, metadata, epoch);
+}
+
+impl<C:RenderListener + Send> RenderTask<C> {
+    pub fn create(id: PipelineId,
+                  port: Receiver<Msg>,
+                  compositor: C,
+                  constellation_chan: ConstellationChan,
+                  font_cache_task: FontCacheTask,
+                  failure_msg: Failure,
+                  opts: Opts,
+                  time_profiler_chan: TimeProfilerChan,
+                  shutdown_chan: Sender<()>) {
+
+        let ConstellationChan(c) = constellation_chan.clone();
+        let fc = font_cache_task.clone();
+
+        spawn_named_with_send_on_failure("RenderTask", proc() {
+            { // Ensures RenderTask and graphics context are destroyed before shutdown msg
+                let native_graphics_context = compositor.get_graphics_metadata().map(
+                    |md| NativePaintingGraphicsContext::from_metadata(&md));
+                let cpu_painting = opts.cpu_painting;
+
+                // FIXME: rust/#5967
+                let mut render_task = RenderTask {
+                    id: id,
+                    port: port,
+                    compositor: compositor,
+                    constellation_chan: constellation_chan,
+                    font_ctx: box FontContext::new(fc.clone()),
+                    opts: opts,
+                    time_profiler_chan: time_profiler_chan,
+
+                    graphics_context: if cpu_painting {
+                        CpuGraphicsContext
+                    } else {
+                        GpuGraphicsContext
+                    },
+
+                    native_graphics_context: native_graphics_context,
+
+                    render_layers: SmallVec1::new(),
+
+                    paint_permission: false,
+                    epoch: Epoch(0),
+                    buffer_map: BufferMap::new(10000000),
+                };
+
+                render_task.start();
+
+                // Destroy all the buffers.
+                match render_task.native_graphics_context.as_ref() {
+                    Some(ctx) => render_task.buffer_map.clear(ctx),
+                    None => (),
+                }
+            }
+
+            debug!("render_task: shutdown_chan send");
+            shutdown_chan.send(());
+        }, FailureMsg(failure_msg), c, true);
+    }
+
+    fn start(&mut self) {
+        debug!("render_task: beginning rendering loop");
+
+        loop {
+            match self.port.recv() {
+                RenderInitMsg(render_layers) => {
+                    self.epoch.next();
+                    self.render_layers = render_layers;
+
+                    if !self.paint_permission {
+                        debug!("render_task: render ready msg");
+                        let ConstellationChan(ref mut c) = self.constellation_chan;
+                        c.send(RendererReadyMsg(self.id));
+                        continue;
+                    }
+
+                    initialize_layers(&mut self.compositor,
+                                      self.id,
+                                      self.epoch,
+                                      self.render_layers.as_slice());
+                }
+                RenderMsg(requests) => {
+                    if !self.paint_permission {
+                        debug!("render_task: render ready msg");
+                        let ConstellationChan(ref mut c) = self.constellation_chan;
+                        c.send(RendererReadyMsg(self.id));
+                        self.compositor.render_msg_discarded();
+                        continue;
+                    }
+
+                    self.compositor.set_render_state(RenderingRenderState);
+
+                    let mut replies = Vec::new();
+                    for RenderRequest { buffer_requests, scale, layer_id, epoch }
+                          in requests.move_iter() {
+                        if self.epoch == epoch {
+                            self.render(&mut replies, buffer_requests, scale, layer_id);
+                        } else {
+                            debug!("renderer epoch mismatch: {:?} != {:?}", self.epoch, epoch);
+                        }
+                    }
+
+                    self.compositor.set_render_state(IdleRenderState);
+
+                    debug!("render_task: returning surfaces");
+                    self.compositor.paint(self.id, self.epoch, replies);
+                }
+                UnusedBufferMsg(unused_buffers) => {
+                    for buffer in unused_buffers.move_iter().rev() {
+                        self.buffer_map.insert(native_graphics_context!(self), buffer);
+                    }
+                }
+                PaintPermissionGranted => {
+                    self.paint_permission = true;
+
+                    // Here we assume that the main layer—the layer responsible for the page size—
+                    // is the first layer. This is a pretty fragile assumption. It will be fixed
+                    // once we use the layers-based scrolling infrastructure for all scrolling.
+                    if self.render_layers.len() > 1 {
+                        self.epoch.next();
+                        initialize_layers(&mut self.compositor,
+                                          self.id,
+                                          self.epoch,
+                                          self.render_layers.as_slice());
+                    }
+                }
+                PaintPermissionRevoked => {
+                    self.paint_permission = false;
+                }
+                ExitMsg(response_ch) => {
+                    debug!("render_task: exitmsg response send");
+                    response_ch.map(|ch| ch.send(()));
+                    break;
+                }
+            }
+        }
+    }
+
+    /// Renders one layer and sends the tiles back to the layer.
+    fn render(&mut self,
+              replies: &mut Vec<(LayerId, Box<LayerBufferSet>)>,
+              tiles: Vec<BufferRequest>,
+              scale: f32,
+              layer_id: LayerId) {
+        time::profile(time::RenderingCategory, self.time_profiler_chan.clone(), || {
+            // FIXME: Try not to create a new array here.
+            let mut new_buffers = vec!();
+
+            // Find the appropriate render layer.
+            let render_layer = match self.render_layers.iter().find(|layer| layer.id == layer_id) {
+                Some(render_layer) => render_layer,
+                None => return,
+            };
+
+            // Divide up the layer into tiles.
+            for tile in tiles.iter() {
+                // Optimize the display list for this tile.
+                let page_rect_au = geometry::f32_rect_to_au_rect(tile.page_rect);
+                let optimizer = DisplayListOptimizer::new(render_layer.display_list.clone(),
+                                                          page_rect_au);
+                let display_list = optimizer.optimize();
+
+                let width = tile.screen_rect.size.width;
+                let height = tile.screen_rect.size.height;
+
+                let size = Size2D(width as i32, height as i32);
+                let draw_target = match self.graphics_context {
+                    CpuGraphicsContext => {
+                        DrawTarget::new(self.opts.render_backend, size, B8G8R8A8)
+                    }
+                    GpuGraphicsContext => {
+                        // FIXME(pcwalton): Cache the components of draw targets
+                        // (texture color buffer, renderbuffers) instead of recreating them.
+                        let draw_target =
+                            DrawTarget::new_with_fbo(self.opts.render_backend,
+                                                     native_graphics_context!(self),
+                                                     size,
+                                                     B8G8R8A8);
+                        draw_target.make_current();
+                        draw_target
+                    }
+                };
+
+                {
+                    // Build the render context.
+                    let mut ctx = RenderContext {
+                        draw_target: &draw_target,
+                        font_ctx: &mut self.font_ctx,
+                        opts: &self.opts,
+                        page_rect: tile.page_rect,
+                        screen_rect: tile.screen_rect,
+                    };
+
+                    // Apply the translation to render the tile we want.
+                    let matrix: Matrix2D<AzFloat> = Matrix2D::identity();
+                    let matrix = matrix.scale(scale as AzFloat, scale as AzFloat);
+                    let matrix = matrix.translate(-(tile.page_rect.origin.x) as AzFloat,
+                                                  -(tile.page_rect.origin.y) as AzFloat);
+                    let matrix = matrix.translate(-(render_layer.position.origin.x as AzFloat),
+                                                  -(render_layer.position.origin.y as AzFloat));
+
+                    ctx.draw_target.set_transform(&matrix);
+
+                    // Clear the buffer.
+                    ctx.clear();
+
+                    // Draw the display list.
+                    profile(time::RenderingDrawingCategory, self.time_profiler_chan.clone(), || {
+                        display_list.draw_into_context(&mut ctx, &matrix);
+                        ctx.draw_target.flush();
+                    });
+                }
+
+                // Extract the texture from the draw target and place it into its slot in the
+                // buffer. If using CPU rendering, upload it first.
+                //
+                // FIXME(pcwalton): We should supply the texture and native surface *to* the
+                // draw target in GPU rendering mode, so that it doesn't have to recreate it.
+                let buffer = match self.graphics_context {
+                    CpuGraphicsContext => {
+                        let mut buffer = match self.buffer_map.find(tile.screen_rect.size) {
+                            Some(buffer) => {
+                                let mut buffer = buffer;
+                                buffer.rect = tile.page_rect;
+                                buffer.screen_pos = tile.screen_rect;
+                                buffer.resolution = scale;
+                                buffer.native_surface.mark_wont_leak();
+                                buffer.painted_with_cpu = true;
+                                buffer.content_age = tile.content_age;
+                                buffer
+                            }
+                            None => {
+                                // Create an empty native surface. We mark it as not leaking
+                                // in case it dies in transit to the compositor task.
+                                let mut native_surface: NativeSurface =
+                                    layers::platform::surface::NativeSurfaceMethods::new(
+                                        native_graphics_context!(self),
+                                        Size2D(width as i32, height as i32),
+                                        width as i32 * 4);
+                                native_surface.mark_wont_leak();
+
+                                box LayerBuffer {
+                                    native_surface: native_surface,
+                                    rect: tile.page_rect,
+                                    screen_pos: tile.screen_rect,
+                                    resolution: scale,
+                                    stride: (width * 4) as uint,
+                                    painted_with_cpu: true,
+                                    content_age: tile.content_age,
+                                }
+                            }
+                        };
+
+                        draw_target.snapshot().get_data_surface().with_data(|data| {
+                            buffer.native_surface.upload(native_graphics_context!(self), data);
+                            debug!("RENDERER uploading to native surface {:d}",
+                                   buffer.native_surface.get_id() as int);
+                        });
+
+                        buffer
+                    }
+                    GpuGraphicsContext => {
+                        draw_target.make_current();
+                        let StolenGLResources {
+                            surface: native_surface
+                        } = draw_target.steal_gl_resources().unwrap();
+
+                        // We mark the native surface as not leaking in case the surfaces
+                        // die on their way to the compositor task.
+                        let mut native_surface: NativeSurface =
+                            NativeSurfaceAzureMethods::from_azure_surface(native_surface);
+                        native_surface.mark_wont_leak();
+
+                        box LayerBuffer {
+                            native_surface: native_surface,
+                            rect: tile.page_rect,
+                            screen_pos: tile.screen_rect,
+                            resolution: scale,
+                            stride: (width * 4) as uint,
+                            painted_with_cpu: false,
+                            content_age: tile.content_age,
+                        }
+                    }
+                };
+
+                new_buffers.push(buffer);
+            }
+
+            let layer_buffer_set = box LayerBufferSet {
+                buffers: new_buffers,
+            };
+
+            replies.push((render_layer.id, layer_buffer_set));
+        })
+    }
+}
+

components/gfx/text/glyph.rs

@@ -0,0 +1,752 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+use servo_util::vec::*;
+use servo_util::range;
+use servo_util::range::{Range, RangeIndex, IntRangeIndex, EachIndex};
+use servo_util::geometry::Au;
+
+use std::cmp::{PartialOrd, PartialEq};
+use std::num::{NumCast, Zero};
+use std::mem;
+use std::u16;
+use std::vec::Vec;
+use geom::point::Point2D;
+
+/// GlyphEntry is a port of Gecko's CompressedGlyph scheme for storing glyph data compactly.
+///
+/// In the common case (reasonable glyph advances, no offsets from the font em-box, and one glyph
+/// per character), we pack glyph advance, glyph id, and some flags into a single u32.
+///
+/// In the uncommon case (multiple glyphs per unicode character, large glyph index/advance, or
+/// glyph offsets), we pack the glyph count into GlyphEntry, and store the other glyph information
+/// in DetailedGlyphStore.
+#[deriving(Clone)]
+struct GlyphEntry {
+    value: u32,
+}
+
+impl GlyphEntry {
+    fn new(value: u32) -> GlyphEntry {
+        GlyphEntry {
+            value: value,
+        }
+    }
+
+    fn initial() -> GlyphEntry {
+        GlyphEntry::new(0)
+    }
+
+    // Creates a GlyphEntry for the common case
+    fn simple(id: GlyphId, advance: Au) -> GlyphEntry {
+        assert!(is_simple_glyph_id(id));
+        assert!(is_simple_advance(advance));
+
+        let id_mask = id as u32;
+        let Au(advance) = advance;
+        let advance_mask = (advance as u32) << GLYPH_ADVANCE_SHIFT as uint;
+
+        GlyphEntry::new(id_mask | advance_mask | FLAG_IS_SIMPLE_GLYPH)
+    }
+
+    // Create a GlyphEntry for uncommon case; should be accompanied by
+    // initialization of the actual DetailedGlyph data in DetailedGlyphStore
+    fn complex(starts_cluster: bool, starts_ligature: bool, glyph_count: int) -> GlyphEntry {
+        assert!(glyph_count <= u16::MAX as int);
+
+        debug!("creating complex glyph entry: starts_cluster={}, starts_ligature={}, \
+                glyph_count={}",
+               starts_cluster,
+               starts_ligature,
+               glyph_count);
+
+        let mut val = FLAG_NOT_MISSING;
+
+        if !starts_cluster {
+            val |= FLAG_NOT_CLUSTER_START;
+        }
+        if !starts_ligature {
+            val |= FLAG_NOT_LIGATURE_GROUP_START;
+        }
+        val |= (glyph_count as u32) << GLYPH_COUNT_SHIFT as uint;
+
+        GlyphEntry::new(val)
+    }
+
+    /// Create a GlyphEntry for the case where glyphs couldn't be found for the specified
+    /// character.
+    fn missing(glyph_count: int) -> GlyphEntry {
+        assert!(glyph_count <= u16::MAX as int);
+
+        GlyphEntry::new((glyph_count as u32) << GLYPH_COUNT_SHIFT as uint)
+    }
+}
+
+/// The id of a particular glyph within a font
+pub type GlyphId = u32;
+
+// TODO: unify with bit flags?
+#[deriving(PartialEq)]
+pub enum BreakType {
+    BreakTypeNone,
+    BreakTypeNormal,
+    BreakTypeHyphen,
+}
+
+static BREAK_TYPE_NONE:   u8 = 0x0;
+static BREAK_TYPE_NORMAL: u8 = 0x1;
+static BREAK_TYPE_HYPHEN: u8 = 0x2;
+
+fn break_flag_to_enum(flag: u8) -> BreakType {
+    if (flag & BREAK_TYPE_NORMAL) != 0 {
+        BreakTypeNormal
+    } else if (flag & BREAK_TYPE_HYPHEN) != 0 {
+        BreakTypeHyphen
+    } else {
+        BreakTypeNone
+    }
+}
+
+fn break_enum_to_flag(e: BreakType) -> u8 {
+    match e {
+        BreakTypeNone   => BREAK_TYPE_NONE,
+        BreakTypeNormal => BREAK_TYPE_NORMAL,
+        BreakTypeHyphen => BREAK_TYPE_HYPHEN,
+    }
+}
+
+// TODO: make this more type-safe.
+
+static FLAG_CHAR_IS_SPACE: u32      = 0x10000000;
+// These two bits store some BREAK_TYPE_* flags
+static FLAG_CAN_BREAK_MASK: u32     = 0x60000000;
+static FLAG_CAN_BREAK_SHIFT: u32    = 29;
+static FLAG_IS_SIMPLE_GLYPH: u32    = 0x80000000;
+
+// glyph advance; in Au's.
+static GLYPH_ADVANCE_MASK: u32      = 0x0FFF0000;
+static GLYPH_ADVANCE_SHIFT: u32     = 16;
+static GLYPH_ID_MASK: u32           = 0x0000FFFF;
+
+// Non-simple glyphs (more than one glyph per char; missing glyph,
+// newline, tab, large advance, or nonzero x/y offsets) may have one
+// or more detailed glyphs associated with them. They are stored in a
+// side array so that there is a 1:1 mapping of GlyphEntry to
+// unicode char.
+
+// The number of detailed glyphs for this char. If the char couldn't
+// be mapped to a glyph (!FLAG_NOT_MISSING), then this actually holds
+// the UTF8 code point instead.
+static GLYPH_COUNT_MASK:              u32 = 0x00FFFF00;
+static GLYPH_COUNT_SHIFT:             u32 = 8;
+// N.B. following Gecko, these are all inverted so that a lot of
+// missing chars can be memset with zeros in one fell swoop.
+static FLAG_NOT_MISSING:              u32 = 0x00000001;
+static FLAG_NOT_CLUSTER_START:        u32 = 0x00000002;
+static FLAG_NOT_LIGATURE_GROUP_START: u32 = 0x00000004;
+
+static FLAG_CHAR_IS_TAB:              u32 = 0x00000008;
+static FLAG_CHAR_IS_NEWLINE:          u32 = 0x00000010;
+//static FLAG_CHAR_IS_LOW_SURROGATE:    u32 = 0x00000020;
+//static CHAR_IDENTITY_FLAGS_MASK:      u32 = 0x00000038;
+
+fn is_simple_glyph_id(id: GlyphId) -> bool {
+    ((id as u32) & GLYPH_ID_MASK) == id
+}
+
+fn is_simple_advance(advance: Au) -> bool {
+    let unsignedAu = advance.to_u32().unwrap();
+    (unsignedAu & (GLYPH_ADVANCE_MASK >> GLYPH_ADVANCE_SHIFT as uint)) == unsignedAu
+}
+
+type DetailedGlyphCount = u16;
+
+// Getters and setters for GlyphEntry. Setter methods are functional,
+// because GlyphEntry is immutable and only a u32 in size.
+impl GlyphEntry {
+    // getter methods
+    #[inline(always)]
+    fn advance(&self) -> Au {
+        NumCast::from((self.value & GLYPH_ADVANCE_MASK) >> GLYPH_ADVANCE_SHIFT as uint).unwrap()
+    }
+
+    fn id(&self) -> GlyphId {
+        self.value & GLYPH_ID_MASK
+    }
+
+    fn is_ligature_start(&self) -> bool {
+        self.has_flag(!FLAG_NOT_LIGATURE_GROUP_START)
+    }
+
+    fn is_cluster_start(&self) -> bool {
+        self.has_flag(!FLAG_NOT_CLUSTER_START)
+    }
+
+    // True if original char was normal (U+0020) space. Other chars may
+    // map to space glyph, but this does not account for them.
+    fn char_is_space(&self) -> bool {
+        self.has_flag(FLAG_CHAR_IS_SPACE)
+    }
+
+    fn char_is_tab(&self) -> bool {
+        !self.is_simple() && self.has_flag(FLAG_CHAR_IS_TAB)
+    }
+
+    fn char_is_newline(&self) -> bool {
+        !self.is_simple() && self.has_flag(FLAG_CHAR_IS_NEWLINE)
+    }
+
+    fn can_break_before(&self) -> BreakType {
+        let flag = ((self.value & FLAG_CAN_BREAK_MASK) >> FLAG_CAN_BREAK_SHIFT as uint) as u8;
+        break_flag_to_enum(flag)
+    }
+
+    // setter methods
+    #[inline(always)]
+    fn set_char_is_space(&self) -> GlyphEntry {
+        GlyphEntry::new(self.value | FLAG_CHAR_IS_SPACE)
+    }
+
+    #[inline(always)]
+    fn set_char_is_tab(&self) -> GlyphEntry {
+        assert!(!self.is_simple());
+        GlyphEntry::new(self.value | FLAG_CHAR_IS_TAB)
+    }
+
+    #[inline(always)]
+    fn set_char_is_newline(&self) -> GlyphEntry {
+        assert!(!self.is_simple());
+        GlyphEntry::new(self.value | FLAG_CHAR_IS_NEWLINE)
+    }
+
+    #[inline(always)]
+    fn set_can_break_before(&self, e: BreakType) -> GlyphEntry {
+        let flag = (break_enum_to_flag(e) as u32) << FLAG_CAN_BREAK_SHIFT as uint;
+        GlyphEntry::new(self.value | flag)
+    }
+
+    // helper methods
+
+    fn glyph_count(&self) -> u16 {
+        assert!(!self.is_simple());
+        ((self.value & GLYPH_COUNT_MASK) >> GLYPH_COUNT_SHIFT as uint) as u16
+    }
+
+    #[inline(always)]
+    fn is_simple(&self) -> bool {
+        self.has_flag(FLAG_IS_SIMPLE_GLYPH)
+    }
+
+    #[inline(always)]
+    fn has_flag(&self, flag: u32) -> bool {
+        (self.value & flag) != 0
+    }
+
+    #[inline(always)]
+    fn adapt_character_flags_of_entry(&self, other: GlyphEntry) -> GlyphEntry {
+        GlyphEntry { value: self.value | other.value }
+    }
+}
+
+// Stores data for a detailed glyph, in the case that several glyphs
+// correspond to one character, or the glyph's data couldn't be packed.
+#[deriving(Clone)]
+struct DetailedGlyph {
+    id: GlyphId,
+    // glyph's advance, in the text's direction (RTL or RTL)
+    advance: Au,
+    // glyph's offset from the font's em-box (from top-left)
+    offset: Point2D<Au>,
+}
+
+impl DetailedGlyph {
+    fn new(id: GlyphId, advance: Au, offset: Point2D<Au>) -> DetailedGlyph {
+        DetailedGlyph {
+            id: id,
+            advance: advance,
+            offset: offset,
+        }
+    }
+}
+
+#[deriving(PartialEq, Clone, Eq)]
+struct DetailedGlyphRecord {
+    // source string offset/GlyphEntry offset in the TextRun
+    entry_offset: CharIndex,
+    // offset into the detailed glyphs buffer
+    detail_offset: int,
+}
+
+impl PartialOrd for DetailedGlyphRecord {
+    fn partial_cmp(&self, other: &DetailedGlyphRecord) -> Option<Ordering> {
+        self.entry_offset.partial_cmp(&other.entry_offset)
+    }
+}
+
+impl Ord for DetailedGlyphRecord {
+    fn cmp(&self, other: &DetailedGlyphRecord) -> Ordering {
+        self.entry_offset.cmp(&other.entry_offset)
+    }
+}
+
+// Manages the lookup table for detailed glyphs. Sorting is deferred
+// until a lookup is actually performed; this matches the expected
+// usage pattern of setting/appending all the detailed glyphs, and
+// then querying without setting.
+struct DetailedGlyphStore {
+    // TODO(pcwalton): Allocation of this buffer is expensive. Consider a small-vector
+    // optimization.
+    detail_buffer: Vec<DetailedGlyph>,
+    // TODO(pcwalton): Allocation of this buffer is expensive. Consider a small-vector
+    // optimization.
+    detail_lookup: Vec<DetailedGlyphRecord>,
+    lookup_is_sorted: bool,
+}
+
+impl<'a> DetailedGlyphStore {
+    fn new() -> DetailedGlyphStore {
+        DetailedGlyphStore {
+            detail_buffer: vec!(), // TODO: default size?
+            detail_lookup: vec!(),
+            lookup_is_sorted: false,
+        }
+    }
+
+    fn add_detailed_glyphs_for_entry(&mut self, entry_offset: CharIndex, glyphs: &[DetailedGlyph]) {
+        let entry = DetailedGlyphRecord {
+            entry_offset: entry_offset,
+            detail_offset: self.detail_buffer.len() as int,
+        };
+
+        debug!("Adding entry[off={}] for detailed glyphs: {:?}", entry_offset, glyphs);
+
+        /* TODO: don't actually assert this until asserts are compiled
+        in/out based on severity, debug/release, etc. This assertion
+        would wreck the complexity of the lookup.
+
+        See Rust Issue #3647, #2228, #3627 for related information.
+
+        do self.detail_lookup.borrow |arr| {
+            assert !arr.contains(entry)
+        }
+        */
+
+        self.detail_lookup.push(entry);
+        self.detail_buffer.push_all(glyphs);
+        self.lookup_is_sorted = false;
+    }
+
+    fn get_detailed_glyphs_for_entry(&'a self, entry_offset: CharIndex, count: u16)
+                                  -> &'a [DetailedGlyph] {
+        debug!("Requesting detailed glyphs[n={}] for entry[off={}]", count, entry_offset);
+
+        // FIXME: Is this right? --pcwalton
+        // TODO: should fix this somewhere else
+        if count == 0 {
+            return self.detail_buffer.slice(0, 0);
+        }
+
+        assert!((count as uint) <= self.detail_buffer.len());
+        assert!(self.lookup_is_sorted);
+
+        let key = DetailedGlyphRecord {
+            entry_offset: entry_offset,
+            detail_offset: 0, // unused
+        };
+
+        let i = self.detail_lookup.as_slice().binary_search_index(&key)
+            .expect("Invalid index not found in detailed glyph lookup table!");
+
+        assert!(i + (count as uint) <= self.detail_buffer.len());
+        // return a slice into the buffer
+        self.detail_buffer.slice(i, i + count as uint)
+    }
+
+    fn get_detailed_glyph_with_index(&'a self,
+                                     entry_offset: CharIndex,
+                                     detail_offset: u16)
+            -> &'a DetailedGlyph {
+        assert!((detail_offset as uint) <= self.detail_buffer.len());
+        assert!(self.lookup_is_sorted);
+
+        let key = DetailedGlyphRecord {
+            entry_offset: entry_offset,
+            detail_offset: 0, // unused
+        };
+
+        let i = self.detail_lookup.as_slice().binary_search_index(&key)
+            .expect("Invalid index not found in detailed glyph lookup table!");
+
+        assert!(i + (detail_offset as uint) < self.detail_buffer.len());
+        &self.detail_buffer[i + (detail_offset as uint)]
+    }
+
+    fn ensure_sorted(&mut self) {
+        if self.lookup_is_sorted {
+            return;
+        }
+
+        // Sorting a unique vector is surprisingly hard. The follwing
+        // code is a good argument for using DVecs, but they require
+        // immutable locations thus don't play well with freezing.
+
+        // Thar be dragons here. You have been warned. (Tips accepted.)
+        let mut unsorted_records: Vec<DetailedGlyphRecord> = vec!();
+        mem::swap(&mut self.detail_lookup, &mut unsorted_records);
+        let mut mut_records : Vec<DetailedGlyphRecord> = unsorted_records;
+        mut_records.sort_by(|a, b| {
+            if a < b {
+                Less
+            } else {
+                Greater
+            }
+        });
+        let mut sorted_records = mut_records;
+        mem::swap(&mut self.detail_lookup, &mut sorted_records);
+
+        self.lookup_is_sorted = true;
+    }
+}
+
+// This struct is used by GlyphStore clients to provide new glyph data.
+// It should be allocated on the stack and passed by reference to GlyphStore.
+pub struct GlyphData {
+    id: GlyphId,
+    advance: Au,
+    offset: Point2D<Au>,
+    is_missing: bool,
+    cluster_start: bool,
+    ligature_start: bool,
+}
+
+impl GlyphData {
+    pub fn new(id: GlyphId,
+               advance: Au,
+               offset: Option<Point2D<Au>>,
+               is_missing: bool,
+               cluster_start: bool,
+               ligature_start: bool)
+            -> GlyphData {
+        GlyphData {
+            id: id,
+            advance: advance,
+            offset: offset.unwrap_or(Zero::zero()),
+            is_missing: is_missing,
+            cluster_start: cluster_start,
+            ligature_start: ligature_start,
+        }
+    }
+}
+
+// This enum is a proxy that's provided to GlyphStore clients when iterating
+// through glyphs (either for a particular TextRun offset, or all glyphs).
+// Rather than eagerly assembling and copying glyph data, it only retrieves
+// values as they are needed from the GlyphStore, using provided offsets.
+pub enum GlyphInfo<'a> {
+    SimpleGlyphInfo(&'a GlyphStore, CharIndex),
+    DetailGlyphInfo(&'a GlyphStore, CharIndex, u16),
+}
+
+impl<'a> GlyphInfo<'a> {
+    pub fn id(self) -> GlyphId {
+        match self {
+            SimpleGlyphInfo(store, entry_i) => store.entry_buffer[entry_i.to_uint()].id(),
+            DetailGlyphInfo(store, entry_i, detail_j) => {
+                store.detail_store.get_detailed_glyph_with_index(entry_i, detail_j).id
+            }
+        }
+    }
+
+    #[inline(always)]
+    // FIXME: Resolution conflicts with IteratorUtil trait so adding trailing _
+    pub fn advance(self) -> Au {
+        match self {
+            SimpleGlyphInfo(store, entry_i) => store.entry_buffer[entry_i.to_uint()].advance(),
+            DetailGlyphInfo(store, entry_i, detail_j) => {
+                store.detail_store.get_detailed_glyph_with_index(entry_i, detail_j).advance
+            }
+        }
+    }
+
+    pub fn offset(self) -> Option<Point2D<Au>> {
+        match self {
+            SimpleGlyphInfo(_, _) => None,
+            DetailGlyphInfo(store, entry_i, detail_j) => {
+                Some(store.detail_store.get_detailed_glyph_with_index(entry_i, detail_j).offset)
+            }
+        }
+    }
+}
+
+/// Stores the glyph data belonging to a text run.
+///
+/// Simple glyphs are stored inline in the `entry_buffer`, detailed glyphs are
+/// stored as pointers into the `detail_store`.
+///
+/// ~~~
+/// +- GlyphStore --------------------------------+
+/// |               +---+---+---+---+---+---+---+ |
+/// | entry_buffer: |   | s |   | s |   | s | s | |  d = detailed
+/// |               +-|-+---+-|-+---+-|-+---+---+ |  s = simple
+/// |                 |       |       |           |
+/// |                 |   +---+-------+           |
+/// |                 |   |                       |
+/// |               +-V-+-V-+                     |
+/// | detail_store: | d | d |                     |
+/// |               +---+---+                     |
+/// +---------------------------------------------+
+/// ~~~
+pub struct GlyphStore {
+    // TODO(pcwalton): Allocation of this buffer is expensive. Consider a small-vector
+    // optimization.
+    /// A buffer of glyphs within the text run, in the order in which they
+    /// appear in the input text
+    entry_buffer: Vec<GlyphEntry>,
+    /// A store of the detailed glyph data. Detailed glyphs contained in the
+    /// `entry_buffer` point to locations in this data structure.
+    detail_store: DetailedGlyphStore,
+
+    is_whitespace: bool,
+}
+
+int_range_index! {
+    #[deriving(Encodable)]
+    #[doc = "An index that refers to a character in a text run. This could \
+             point to the middle of a glyph."]
+    struct CharIndex(int)
+}
+
+impl<'a> GlyphStore {
+    // Initializes the glyph store, but doesn't actually shape anything.
+    // Use the set_glyph, set_glyphs() methods to store glyph data.
+    pub fn new(length: int, is_whitespace: bool) -> GlyphStore {
+        assert!(length > 0);
+
+        GlyphStore {
+            entry_buffer: Vec::from_elem(length as uint, GlyphEntry::initial()),
+            detail_store: DetailedGlyphStore::new(),
+            is_whitespace: is_whitespace,
+        }
+    }
+
+    pub fn char_len(&self) -> CharIndex {
+        CharIndex(self.entry_buffer.len() as int)
+    }
+
+    pub fn is_whitespace(&self) -> bool {
+        self.is_whitespace
+    }
+
+    pub fn finalize_changes(&mut self) {
+        self.detail_store.ensure_sorted();
+    }
+
+    pub fn add_glyph_for_char_index(&mut self, i: CharIndex, data: &GlyphData) {
+        fn glyph_is_compressible(data: &GlyphData) -> bool {
+            is_simple_glyph_id(data.id)
+                && is_simple_advance(data.advance)
+                && data.offset.is_zero()
+                && data.cluster_start  // others are stored in detail buffer
+        }
+
+        assert!(data.ligature_start); // can't compress ligature continuation glyphs.
+        assert!(i < self.char_len());
+
+        let entry = match (data.is_missing, glyph_is_compressible(data)) {
+            (true, _) => GlyphEntry::missing(1),
+            (false, true) => GlyphEntry::simple(data.id, data.advance),
+            (false, false) => {
+                let glyph = [DetailedGlyph::new(data.id, data.advance, data.offset)];
+                self.detail_store.add_detailed_glyphs_for_entry(i, glyph);
+                GlyphEntry::complex(data.cluster_start, data.ligature_start, 1)
+            }
+        }.adapt_character_flags_of_entry(self.entry_buffer[i.to_uint()]);
+
+        *self.entry_buffer.get_mut(i.to_uint()) = entry;
+    }
+
+    pub fn add_glyphs_for_char_index(&mut self, i: CharIndex, data_for_glyphs: &[GlyphData]) {
+        assert!(i < self.char_len());
+        assert!(data_for_glyphs.len() > 0);
+
+        let glyph_count = data_for_glyphs.len() as int;
+
+        let first_glyph_data = data_for_glyphs[0];
+        let entry = match first_glyph_data.is_missing {
+            true  => GlyphEntry::missing(glyph_count),
+            false => {
+                let glyphs_vec = Vec::from_fn(glyph_count as uint, |i| {
+                    DetailedGlyph::new(data_for_glyphs[i].id,
+                                       data_for_glyphs[i].advance,
+                                       data_for_glyphs[i].offset)
+                });
+
+                self.detail_store.add_detailed_glyphs_for_entry(i, glyphs_vec.as_slice());
+                GlyphEntry::complex(first_glyph_data.cluster_start,
+                                    first_glyph_data.ligature_start,
+                                    glyph_count)
+            }
+        }.adapt_character_flags_of_entry(self.entry_buffer[i.to_uint()]);
+
+        debug!("Adding multiple glyphs[idx={}, count={}]: {:?}", i, glyph_count, entry);
+
+        *self.entry_buffer.get_mut(i.to_uint()) = entry;
+    }
+
+    // used when a character index has no associated glyph---for example, a ligature continuation.
+    pub fn add_nonglyph_for_char_index(&mut self, i: CharIndex, cluster_start: bool, ligature_start: bool) {
+        assert!(i < self.char_len());
+
+        let entry = GlyphEntry::complex(cluster_start, ligature_start, 0);
+        debug!("adding spacer for chracter without associated glyph[idx={}]", i);
+
+        *self.entry_buffer.get_mut(i.to_uint()) = entry;
+    }
+
+    pub fn iter_glyphs_for_char_index(&'a self, i: CharIndex) -> GlyphIterator<'a> {
+        self.iter_glyphs_for_char_range(&Range::new(i, CharIndex(1)))
+    }
+
+    #[inline]
+    pub fn iter_glyphs_for_char_range(&'a self, rang: &Range<CharIndex>) -> GlyphIterator<'a> {
+        if rang.begin() >= self.char_len() {
+            fail!("iter_glyphs_for_range: range.begin beyond length!");
+        }
+        if rang.end() > self.char_len() {
+            fail!("iter_glyphs_for_range: range.end beyond length!");
+        }
+
+        GlyphIterator {
+            store:       self,
+            char_index:  rang.begin(),
+            char_range:  rang.each_index(),
+            glyph_range: None,
+        }
+    }
+
+    #[inline]
+    pub fn advance_for_char_range(&self, rang: &Range<CharIndex>) -> Au {
+        self.iter_glyphs_for_char_range(rang)
+            .fold(Au(0), |advance, (_, glyph)| advance + glyph.advance())
+    }
+
+    // getter methods
+    pub fn char_is_space(&self, i: CharIndex) -> bool {
+        assert!(i < self.char_len());
+        self.entry_buffer[i.to_uint()].char_is_space()
+    }
+
+    pub fn char_is_tab(&self, i: CharIndex) -> bool {
+        assert!(i < self.char_len());
+        self.entry_buffer[i.to_uint()].char_is_tab()
+    }
+
+    pub fn char_is_newline(&self, i: CharIndex) -> bool {
+        assert!(i < self.char_len());
+        self.entry_buffer[i.to_uint()].char_is_newline()
+    }
+
+    pub fn is_ligature_start(&self, i: CharIndex) -> bool {
+        assert!(i < self.char_len());
+        self.entry_buffer[i.to_uint()].is_ligature_start()
+    }
+
+    pub fn is_cluster_start(&self, i: CharIndex) -> bool {
+        assert!(i < self.char_len());
+        self.entry_buffer[i.to_uint()].is_cluster_start()
+    }
+
+    pub fn can_break_before(&self, i: CharIndex) -> BreakType {
+        assert!(i < self.char_len());
+        self.entry_buffer[i.to_uint()].can_break_before()
+    }
+
+    // setter methods
+    pub fn set_char_is_space(&mut self, i: CharIndex) {
+        assert!(i < self.char_len());
+        let entry = self.entry_buffer[i.to_uint()];
+        *self.entry_buffer.get_mut(i.to_uint()) = entry.set_char_is_space();
+    }
+
+    pub fn set_char_is_tab(&mut self, i: CharIndex) {
+        assert!(i < self.char_len());
+        let entry = self.entry_buffer[i.to_uint()];
+        *self.entry_buffer.get_mut(i.to_uint()) = entry.set_char_is_tab();
+    }
+
+    pub fn set_char_is_newline(&mut self, i: CharIndex) {
+        assert!(i < self.char_len());
+        let entry = self.entry_buffer[i.to_uint()];
+        *self.entry_buffer.get_mut(i.to_uint()) = entry.set_char_is_newline();
+    }
+
+    pub fn set_can_break_before(&mut self, i: CharIndex, t: BreakType) {
+        assert!(i < self.char_len());
+        let entry = self.entry_buffer[i.to_uint()];
+        *self.entry_buffer.get_mut(i.to_uint()) = entry.set_can_break_before(t);
+    }
+}
+
+/// An iterator over the glyphs in a character range in a `GlyphStore`.
+pub struct GlyphIterator<'a> {
+    store:       &'a GlyphStore,
+    char_index:  CharIndex,
+    char_range:  EachIndex<int, CharIndex>,
+    glyph_range: Option<EachIndex<int, CharIndex>>,
+}
+
+impl<'a> GlyphIterator<'a> {
+    // Slow path when there is a glyph range.
+    #[inline(never)]
+    fn next_glyph_range(&mut self) -> Option<(CharIndex, GlyphInfo<'a>)> {
+        match self.glyph_range.get_mut_ref().next() {
+            Some(j) => Some((self.char_index,
+                DetailGlyphInfo(self.store, self.char_index, j.get() as u16 /* ??? */))),
+            None => {
+                // No more glyphs for current character.  Try to get another.
+                self.glyph_range = None;
+                self.next()
+            }
+        }
+    }
+
+    // Slow path when there is a complex glyph.
+    #[inline(never)]
+    fn next_complex_glyph(&mut self, entry: &GlyphEntry, i: CharIndex)
+                          -> Option<(CharIndex, GlyphInfo<'a>)> {
+        let glyphs = self.store.detail_store.get_detailed_glyphs_for_entry(i, entry.glyph_count());
+        self.glyph_range = Some(range::each_index(CharIndex(0), CharIndex(glyphs.len() as int)));
+        self.next()
+    }
+}
+
+impl<'a> Iterator<(CharIndex, GlyphInfo<'a>)> for GlyphIterator<'a> {
+    // I tried to start with something simpler and apply FlatMap, but the
+    // inability to store free variables in the FlatMap struct was problematic.
+    //
+    // This function consists of the fast path and is designed to be inlined into its caller. The
+    // slow paths, which should not be inlined, are `next_glyph_range()` and
+    // `next_complex_glyph()`.
+    #[inline(always)]
+    fn next(&mut self) -> Option<(CharIndex, GlyphInfo<'a>)> {
+        // Would use 'match' here but it borrows contents in a way that
+        // interferes with mutation.
+        if self.glyph_range.is_some() {
+            self.next_glyph_range()
+        } else {
+            // No glyph range. Look at next character.
+            self.char_range.next().and_then(|i| {
+                self.char_index = i;
+                assert!(i < self.store.char_len());
+                let entry = self.store.entry_buffer[i.to_uint()];
+                if entry.is_simple() {
+                    Some((self.char_index, SimpleGlyphInfo(self.store, i)))
+                } else {
+                    // Fall back to the slow path.
+                    self.next_complex_glyph(&entry, i)
+                }
+            })
+        }
+    }
+}

components/gfx/text/mod.rs

@@ -0,0 +1,18 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/* This file exists just to make it easier to import things inside of
+ ./text/ without specifying the file they came out of imports.
+
+Note that you still must define each of the files as a module in
+servo.rc. This is not ideal and may be changed in the future. */
+
+pub use text::shaping::Shaper;
+pub use text::text_run::TextRun;
+
+pub mod glyph;
+#[path="shaping/mod.rs"] pub mod shaping;
+pub mod text_run;
+pub mod util;
+

components/gfx/text/shaping/harfbuzz.rs

@@ -0,0 +1,541 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+extern crate harfbuzz;
+
+use font::{Font, FontHandleMethods, FontTableMethods, FontTableTag};
+use platform::font::FontTable;
+use text::glyph::{CharIndex, GlyphStore, GlyphId, GlyphData};
+use text::shaping::ShaperMethods;
+use text::util::{float_to_fixed, fixed_to_float};
+
+use geom::Point2D;
+use harfbuzz::{HB_MEMORY_MODE_READONLY, HB_DIRECTION_LTR};
+use harfbuzz::{hb_blob_create, hb_face_create_for_tables};
+use harfbuzz::{hb_blob_t};
+use harfbuzz::{hb_bool_t};
+use harfbuzz::{hb_buffer_add_utf8};
+use harfbuzz::{hb_buffer_destroy};
+use harfbuzz::{hb_buffer_get_glyph_positions};
+use harfbuzz::{hb_buffer_set_direction};
+use harfbuzz::{hb_face_destroy};
+use harfbuzz::{hb_face_t, hb_font_t};
+use harfbuzz::{hb_font_create};
+use harfbuzz::{hb_font_destroy, hb_buffer_create};
+use harfbuzz::{hb_font_funcs_create};
+use harfbuzz::{hb_font_funcs_destroy};
+use harfbuzz::{hb_font_funcs_set_glyph_func};
+use harfbuzz::{hb_font_funcs_set_glyph_h_advance_func};
+use harfbuzz::{hb_font_funcs_set_glyph_h_kerning_func};
+use harfbuzz::{hb_font_funcs_t, hb_buffer_t, hb_codepoint_t};
+use harfbuzz::{hb_font_set_funcs};
+use harfbuzz::{hb_font_set_ppem};
+use harfbuzz::{hb_font_set_scale};
+use harfbuzz::{hb_glyph_info_t};
+use harfbuzz::{hb_glyph_position_t};
+use harfbuzz::{hb_position_t, hb_tag_t};
+use harfbuzz::{hb_shape, hb_buffer_get_glyph_infos};
+use libc::{c_uint, c_int, c_void, c_char};
+use servo_util::geometry::Au;
+use servo_util::range::Range;
+use std::mem;
+use std::char;
+use std::cmp;
+use std::ptr;
+
+static NO_GLYPH: i32 = -1;
+static CONTINUATION_BYTE: i32 = -2;
+
+pub struct ShapedGlyphData {
+    count: int,
+    glyph_infos: *mut hb_glyph_info_t,
+    pos_infos: *mut hb_glyph_position_t,
+}
+
+pub struct ShapedGlyphEntry {
+    codepoint: GlyphId,
+    advance: Au,
+    offset: Option<Point2D<Au>>,
+}
+
+impl ShapedGlyphData {
+    pub fn new(buffer: *mut hb_buffer_t) -> ShapedGlyphData {
+        unsafe {
+            let mut glyph_count = 0;
+            let glyph_infos = hb_buffer_get_glyph_infos(buffer, &mut glyph_count);
+            let glyph_count = glyph_count as int;
+            assert!(glyph_infos.is_not_null());
+            let mut pos_count = 0;
+            let pos_infos = hb_buffer_get_glyph_positions(buffer, &mut pos_count);
+            let pos_count = pos_count as int;
+            assert!(pos_infos.is_not_null());
+            assert!(glyph_count == pos_count);
+
+            ShapedGlyphData {
+                count: glyph_count,
+                glyph_infos: glyph_infos,
+                pos_infos: pos_infos,
+            }
+        }
+    }
+
+    #[inline(always)]
+    fn byte_offset_of_glyph(&self, i: int) -> int {
+        assert!(i < self.count);
+
+        unsafe {
+            let glyph_info_i = self.glyph_infos.offset(i);
+            (*glyph_info_i).cluster as int
+        }
+    }
+
+    pub fn len(&self) -> int {
+        self.count
+    }
+
+    /// Returns shaped glyph data for one glyph, and updates the y-position of the pen.
+    pub fn get_entry_for_glyph(&self, i: int, y_pos: &mut Au) -> ShapedGlyphEntry {
+        assert!(i < self.count);
+
+        unsafe {
+            let glyph_info_i = self.glyph_infos.offset(i);
+            let pos_info_i = self.pos_infos.offset(i);
+            let x_offset = Shaper::fixed_to_float((*pos_info_i).x_offset);
+            let y_offset = Shaper::fixed_to_float((*pos_info_i).y_offset);
+            let x_advance = Shaper::fixed_to_float((*pos_info_i).x_advance);
+            let y_advance = Shaper::fixed_to_float((*pos_info_i).y_advance);
+
+            let x_offset = Au::from_frac_px(x_offset);
+            let y_offset = Au::from_frac_px(y_offset);
+            let x_advance = Au::from_frac_px(x_advance);
+            let y_advance = Au::from_frac_px(y_advance);
+
+            let offset = if x_offset == Au(0) && y_offset == Au(0) && y_advance == Au(0) {
+                None
+            } else {
+                // adjust the pen..
+                if y_advance > Au(0) {
+                    *y_pos = *y_pos - y_advance;
+                }
+
+                Some(Point2D(x_offset, *y_pos - y_offset))
+            };
+
+            ShapedGlyphEntry {
+                codepoint: (*glyph_info_i).codepoint as GlyphId,
+                advance: x_advance,
+                offset: offset,
+            }
+        }
+    }
+}
+
+pub struct Shaper {
+    hb_face: *mut hb_face_t,
+    hb_font: *mut hb_font_t,
+    hb_funcs: *mut hb_font_funcs_t,
+}
+
+#[unsafe_destructor]
+impl Drop for Shaper {
+    fn drop(&mut self) {
+        unsafe {
+            assert!(self.hb_face.is_not_null());
+            hb_face_destroy(self.hb_face);
+
+            assert!(self.hb_font.is_not_null());
+            hb_font_destroy(self.hb_font);
+
+            assert!(self.hb_funcs.is_not_null());
+            hb_font_funcs_destroy(self.hb_funcs);
+        }
+    }
+}
+
+impl Shaper {
+    pub fn new(font: &mut Font) -> Shaper {
+        unsafe {
+            // Indirection for Rust Issue #6248, dynamic freeze scope artifically extended
+            let font_ptr = font as *mut Font;
+            let hb_face: *mut hb_face_t = hb_face_create_for_tables(get_font_table_func,
+                                                                    font_ptr as *mut c_void,
+                                                                    None);
+            let hb_font: *mut hb_font_t = hb_font_create(hb_face);
+
+            // Set points-per-em. if zero, performs no hinting in that direction.
+            let pt_size = font.pt_size;
+            hb_font_set_ppem(hb_font, pt_size as c_uint, pt_size as c_uint);
+
+            // Set scaling. Note that this takes 16.16 fixed point.
+            hb_font_set_scale(hb_font,
+                              Shaper::float_to_fixed(pt_size) as c_int,
+                              Shaper::float_to_fixed(pt_size) as c_int);
+
+            // configure static function callbacks.
+            // NB. This funcs structure could be reused globally, as it never changes.
+            let hb_funcs: *mut hb_font_funcs_t = hb_font_funcs_create();
+            hb_font_funcs_set_glyph_func(hb_funcs, glyph_func, ptr::mut_null(), None);
+            hb_font_funcs_set_glyph_h_advance_func(hb_funcs, glyph_h_advance_func, ptr::mut_null(), None);
+            hb_font_funcs_set_glyph_h_kerning_func(hb_funcs, glyph_h_kerning_func, ptr::mut_null(), ptr::mut_null());
+            hb_font_set_funcs(hb_font, hb_funcs, font_ptr as *mut c_void, None);
+
+            Shaper {
+                hb_face: hb_face,
+                hb_font: hb_font,
+                hb_funcs: hb_funcs,
+            }
+        }
+    }
+
+    fn float_to_fixed(f: f64) -> i32 {
+        float_to_fixed(16, f)
+    }
+
+    fn fixed_to_float(i: hb_position_t) -> f64 {
+        fixed_to_float(16, i)
+    }
+}
+
+impl ShaperMethods for Shaper {
+    /// Calculate the layout metrics associated with the given text when rendered in a specific
+    /// font.
+    fn shape_text(&self, text: &str, glyphs: &mut GlyphStore) {
+        unsafe {
+            let hb_buffer: *mut hb_buffer_t = hb_buffer_create();
+            hb_buffer_set_direction(hb_buffer, HB_DIRECTION_LTR);
+
+            hb_buffer_add_utf8(hb_buffer,
+                               text.as_ptr() as *const c_char,
+                               text.len() as c_int,
+                               0,
+                               text.len() as c_int);
+
+            hb_shape(self.hb_font, hb_buffer, ptr::mut_null(), 0);
+            self.save_glyph_results(text, glyphs, hb_buffer);
+            hb_buffer_destroy(hb_buffer);
+        }
+    }
+}
+
+impl Shaper {
+    fn save_glyph_results(&self, text: &str, glyphs: &mut GlyphStore, buffer: *mut hb_buffer_t) {
+        let glyph_data = ShapedGlyphData::new(buffer);
+        let glyph_count = glyph_data.len();
+        let byte_max = text.len() as int;
+        let char_max = text.char_len() as int;
+
+        // GlyphStore records are indexed by character, not byte offset.
+        // so, we must be careful to increment this when saving glyph entries.
+        let mut char_idx = CharIndex(0);
+
+        assert!(glyph_count <= char_max);
+
+        debug!("Shaped text[char count={}], got back {} glyph info records.",
+               char_max,
+               glyph_count);
+
+        if char_max != glyph_count {
+            debug!("NOTE: Since these are not equal, we probably have been given some complex \
+                    glyphs.");
+        }
+
+        // make map of what chars have glyphs
+        let mut byteToGlyph: Vec<i32>;
+
+        // fast path: all chars are single-byte.
+        if byte_max == char_max {
+            byteToGlyph = Vec::from_elem(byte_max as uint, NO_GLYPH);
+        } else {
+            byteToGlyph = Vec::from_elem(byte_max as uint, CONTINUATION_BYTE);
+            for (i, _) in text.char_indices() {
+                *byteToGlyph.get_mut(i) = NO_GLYPH;
+            }
+        }
+
+        debug!("(glyph idx) -> (text byte offset)");
+        for i in range(0, glyph_data.len()) {
+            // loc refers to a *byte* offset within the utf8 string.
+            let loc = glyph_data.byte_offset_of_glyph(i);
+            if loc < byte_max {
+                assert!(*byteToGlyph.get(loc as uint) != CONTINUATION_BYTE);
+                *byteToGlyph.get_mut(loc as uint) = i as i32;
+            } else {
+                debug!("ERROR: tried to set out of range byteToGlyph: idx={}, glyph idx={}",
+                       loc,
+                       i);
+            }
+            debug!("{} -> {}", i, loc);
+        }
+
+        debug!("text: {:s}", text);
+        debug!("(char idx): char->(glyph index):");
+        for (i, ch) in text.char_indices() {
+            debug!("{}: {} --> {:d}", i, ch, *byteToGlyph.get(i) as int);
+        }
+
+        // some helpers
+        let mut glyph_span: Range<int> = Range::empty();
+        // this span contains first byte of first char, to last byte of last char in range.
+        // so, end() points to first byte of last+1 char, if it's less than byte_max.
+        let mut char_byte_span: Range<int> = Range::empty();
+        let mut y_pos = Au(0);
+
+        // main loop over each glyph. each iteration usually processes 1 glyph and 1+ chars.
+        // in cases with complex glyph-character assocations, 2+ glyphs and 1+ chars can be
+        // processed.
+        while glyph_span.begin() < glyph_count {
+            // start by looking at just one glyph.
+            glyph_span.extend_by(1);
+            debug!("Processing glyph at idx={}", glyph_span.begin());
+
+            let char_byte_start = glyph_data.byte_offset_of_glyph(glyph_span.begin());
+            char_byte_span.reset(char_byte_start, 0);
+
+            // find a range of chars corresponding to this glyph, plus
+            // any trailing chars that do not have associated glyphs.
+            while char_byte_span.end() < byte_max {
+                let range = text.char_range_at(char_byte_span.end() as uint);
+                drop(range.ch);
+                char_byte_span.extend_to(range.next as int);
+
+                debug!("Processing char byte span: off={}, len={} for glyph idx={}",
+                       char_byte_span.begin(), char_byte_span.length(), glyph_span.begin());
+
+                while char_byte_span.end() != byte_max &&
+                        byteToGlyph[char_byte_span.end() as uint] == NO_GLYPH {
+                    debug!("Extending char byte span to include byte offset={} with no associated \
+                            glyph", char_byte_span.end());
+                    let range = text.char_range_at(char_byte_span.end() as uint);
+                    drop(range.ch);
+                    char_byte_span.extend_to(range.next as int);
+                }
+
+                // extend glyph range to max glyph index covered by char_span,
+                // in cases where one char made several glyphs and left some unassociated chars.
+                let mut max_glyph_idx = glyph_span.end();
+                for i in char_byte_span.each_index() {
+                    if byteToGlyph[i as uint] > NO_GLYPH {
+                        max_glyph_idx = cmp::max(byteToGlyph[i as uint] as int + 1, max_glyph_idx);
+                    }
+                }
+
+                if max_glyph_idx > glyph_span.end() {
+                    glyph_span.extend_to(max_glyph_idx);
+                    debug!("Extended glyph span (off={}, len={}) to cover char byte span's max \
+                            glyph index",
+                           glyph_span.begin(), glyph_span.length());
+                }
+
+
+                // if there's just one glyph, then we don't need further checks.
+                if glyph_span.length() == 1 { break; }
+
+                // if no glyphs were found yet, extend the char byte range more.
+                if glyph_span.length() == 0 { continue; }
+
+                debug!("Complex (multi-glyph to multi-char) association found. This case \
+                        probably doesn't work.");
+
+                let mut all_glyphs_are_within_cluster: bool = true;
+                for j in glyph_span.each_index() {
+                    let loc = glyph_data.byte_offset_of_glyph(j);
+                    if !char_byte_span.contains(loc) {
+                        all_glyphs_are_within_cluster = false;
+                        break
+                    }
+                }
+
+                debug!("All glyphs within char_byte_span cluster?: {}",
+                       all_glyphs_are_within_cluster);
+
+                // found a valid range; stop extending char_span.
+                if all_glyphs_are_within_cluster {
+                    break
+                }
+            }
+
+            // character/glyph clump must contain characters.
+            assert!(char_byte_span.length() > 0);
+            // character/glyph clump must contain glyphs.
+            assert!(glyph_span.length() > 0);
+
+            // now char_span is a ligature clump, formed by the glyphs in glyph_span.
+            // we need to find the chars that correspond to actual glyphs (char_extended_span),
+            //and set glyph info for those and empty infos for the chars that are continuations.
+
+            // a simple example:
+            // chars:  'f'     't'   't'
+            // glyphs: 'ftt'   ''    ''
+            // cgmap:  t        f     f
+            // gspan:  [-]
+            // cspan:  [-]
+            // covsp:  [---------------]
+
+            let mut covered_byte_span = char_byte_span.clone();
+            // extend, clipping at end of text range.
+            while covered_byte_span.end() < byte_max
+                    && byteToGlyph[covered_byte_span.end() as uint] == NO_GLYPH {
+                let range = text.char_range_at(covered_byte_span.end() as uint);
+                drop(range.ch);
+                covered_byte_span.extend_to(range.next as int);
+            }
+
+            if covered_byte_span.begin() >= byte_max {
+                // oops, out of range. clip and forget this clump.
+                let end = glyph_span.end(); // FIXME: borrow checker workaround
+                glyph_span.reset(end, 0);
+                let end = char_byte_span.end(); // FIXME: borrow checker workaround
+                char_byte_span.reset(end, 0);
+            }
+
+            // clamp to end of text. (I don't think this will be necessary, but..)
+            let end = covered_byte_span.end(); // FIXME: borrow checker workaround
+            covered_byte_span.extend_to(cmp::min(end, byte_max));
+
+            // fast path: 1-to-1 mapping of single char and single glyph.
+            if glyph_span.length() == 1 {
+                // TODO(Issue #214): cluster ranges need to be computed before
+                // shaping, and then consulted here.
+                // for now, just pretend that every character is a cluster start.
+                // (i.e., pretend there are no combining character sequences).
+                // 1-to-1 mapping of character to glyph also treated as ligature start.
+                let shape = glyph_data.get_entry_for_glyph(glyph_span.begin(), &mut y_pos);
+                let data = GlyphData::new(shape.codepoint,
+                                          shape.advance,
+                                          shape.offset,
+                                          false,
+                                          true,
+                                          true);
+                glyphs.add_glyph_for_char_index(char_idx, &data);
+            } else {
+                // collect all glyphs to be assigned to the first character.
+                let mut datas = vec!();
+
+                for glyph_i in glyph_span.each_index() {
+                    let shape = glyph_data.get_entry_for_glyph(glyph_i, &mut y_pos);
+                    datas.push(GlyphData::new(shape.codepoint,
+                                              shape.advance,
+                                              shape.offset,
+                                              false, // not missing
+                                              true,  // treat as cluster start
+                                              glyph_i > glyph_span.begin()));
+                                              // all but first are ligature continuations
+                }
+
+                // now add the detailed glyph entry.
+                glyphs.add_glyphs_for_char_index(char_idx, datas.as_slice());
+
+                // set the other chars, who have no glyphs
+                let mut i = covered_byte_span.begin();
+                loop {
+                    let range = text.char_range_at(i as uint);
+                    drop(range.ch);
+                    i = range.next as int;
+                    if i >= covered_byte_span.end() { break; }
+                    char_idx = char_idx + CharIndex(1);
+                    glyphs.add_nonglyph_for_char_index(char_idx, false, false);
+                }
+            }
+
+            // shift up our working spans past things we just handled.
+            let end = glyph_span.end(); // FIXME: borrow checker workaround
+            glyph_span.reset(end, 0);
+            let end = char_byte_span.end();; // FIXME: borrow checker workaround
+            char_byte_span.reset(end, 0);
+            char_idx = char_idx + CharIndex(1);
+        }
+
+        // this must be called after adding all glyph data; it sorts the
+        // lookup table for finding detailed glyphs by associated char index.
+        glyphs.finalize_changes();
+    }
+}
+
+/// Callbacks from Harfbuzz when font map and glyph advance lookup needed.
+extern fn glyph_func(_: *mut hb_font_t,
+                     font_data: *mut c_void,
+                     unicode: hb_codepoint_t,
+                     _: hb_codepoint_t,
+                     glyph: *mut hb_codepoint_t,
+                     _: *mut c_void)
+                  -> hb_bool_t {
+    let font: *const Font = font_data as *const Font;
+    assert!(font.is_not_null());
+
+    unsafe {
+        match (*font).glyph_index(char::from_u32(unicode).unwrap()) {
+            Some(g) => {
+                *glyph = g as hb_codepoint_t;
+                true as hb_bool_t
+            }
+            None => false as hb_bool_t
+        }
+    }
+}
+
+extern fn glyph_h_advance_func(_: *mut hb_font_t,
+                               font_data: *mut c_void,
+                               glyph: hb_codepoint_t,
+                               _: *mut c_void)
+                            -> hb_position_t {
+    let font: *mut Font = font_data as *mut Font;
+    assert!(font.is_not_null());
+
+    unsafe {
+        let advance = (*font).glyph_h_advance(glyph as GlyphId);
+        Shaper::float_to_fixed(advance)
+    }
+}
+
+extern fn glyph_h_kerning_func(_: *mut hb_font_t,
+                               font_data: *mut c_void,
+                               first_glyph: hb_codepoint_t,
+                               second_glyph: hb_codepoint_t,
+                               _: *mut c_void)
+                            -> hb_position_t {
+    let font: *mut Font = font_data as *mut Font;
+    assert!(font.is_not_null());
+
+    unsafe {
+        let advance = (*font).glyph_h_kerning(first_glyph as GlyphId, second_glyph as GlyphId);
+        Shaper::float_to_fixed(advance)
+    }
+}
+
+// Callback to get a font table out of a font.
+extern fn get_font_table_func(_: *mut hb_face_t, tag: hb_tag_t, user_data: *mut c_void) -> *mut hb_blob_t {
+    unsafe {
+        let font: *const Font = user_data as *const Font;
+        assert!(font.is_not_null());
+
+        // TODO(Issue #197): reuse font table data, which will change the unsound trickery here.
+        match (*font).get_table_for_tag(tag as FontTableTag) {
+            None => ptr::mut_null(),
+            Some(ref font_table) => {
+                let skinny_font_table_ptr: *const FontTable = font_table;   // private context
+
+                let mut blob: *mut hb_blob_t = ptr::mut_null();
+                (*skinny_font_table_ptr).with_buffer(|buf: *const u8, len: uint| {
+                    // HarfBuzz calls `destroy_blob_func` when the buffer is no longer needed.
+                    blob = hb_blob_create(buf as *const c_char,
+                                          len as c_uint,
+                                          HB_MEMORY_MODE_READONLY,
+                                          mem::transmute(skinny_font_table_ptr),
+                                          destroy_blob_func);
+                });
+
+                assert!(blob.is_not_null());
+                blob
+            }
+        }
+    }
+}
+
+// TODO(Issue #197): reuse font table data, which will change the unsound trickery here.
+// In particular, we'll need to cast to a boxed, rather than owned, FontTable.
+
+// even better, should cache the harfbuzz blobs directly instead of recreating a lot.
+extern fn destroy_blob_func(_: *mut c_void) {
+    // TODO: Previous code here was broken. Rewrite.
+}

components/gfx/text/shaping/mod.rs

@@ -0,0 +1,19 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+//! Shaper encapsulates a specific shaper, such as Harfbuzz,
+//! Uniscribe, Pango, or Coretext.
+//!
+//! Currently, only harfbuzz bindings are implemented.
+
+use text::glyph::GlyphStore;
+
+pub use Shaper = text::shaping::harfbuzz::Shaper;
+
+pub mod harfbuzz;
+
+pub trait ShaperMethods {
+    fn shape_text(&self, text: &str, glyphs: &mut GlyphStore);
+}
+

components/gfx/text/text_run.rs

@@ -0,0 +1,271 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+use font::{Font, RunMetrics, FontMetrics};
+use servo_util::geometry::Au;
+use servo_util::range::Range;
+use servo_util::vec::{Comparator, FullBinarySearchMethods};
+use std::slice::Items;
+use sync::Arc;
+use text::glyph::{CharIndex, GlyphStore};
+use font::FontHandleMethods;
+use platform::font_template::FontTemplateData;
+
+/// A single "paragraph" of text in one font size and style.
+#[deriving(Clone)]
+pub struct TextRun {
+    pub text: Arc<String>,
+    pub font_template: Arc<FontTemplateData>,
+    pub pt_size: f64,
+    pub font_metrics: FontMetrics,
+    /// The glyph runs that make up this text run.
+    pub glyphs: Arc<Vec<GlyphRun>>,
+}
+
+/// A single series of glyphs within a text run.
+#[deriving(Clone)]
+pub struct GlyphRun {
+    /// The glyphs.
+    glyph_store: Arc<GlyphStore>,
+    /// The range of characters in the containing run.
+    range: Range<CharIndex>,
+}
+
+pub struct SliceIterator<'a> {
+    glyph_iter: Items<'a, GlyphRun>,
+    range:      Range<CharIndex>,
+}
+
+struct CharIndexComparator;
+
+impl Comparator<CharIndex,GlyphRun> for CharIndexComparator {
+    fn compare(&self, key: &CharIndex, value: &GlyphRun) -> Ordering {
+        if *key < value.range.begin() {
+            Less
+        } else if *key >= value.range.end() {
+            Greater
+        } else {
+            Equal
+        }
+    }
+}
+
+impl<'a> Iterator<(&'a GlyphStore, CharIndex, Range<CharIndex>)> for SliceIterator<'a> {
+    // inline(always) due to the inefficient rt failures messing up inline heuristics, I think.
+    #[inline(always)]
+    fn next(&mut self) -> Option<(&'a GlyphStore, CharIndex, Range<CharIndex>)> {
+        let slice_glyphs = self.glyph_iter.next();
+        if slice_glyphs.is_none() {
+            return None;
+        }
+        let slice_glyphs = slice_glyphs.unwrap();
+
+        let mut char_range = self.range.intersect(&slice_glyphs.range);
+        let slice_range_begin = slice_glyphs.range.begin();
+        char_range.shift_by(-slice_range_begin);
+        if !char_range.is_empty() {
+            return Some((&*slice_glyphs.glyph_store, slice_range_begin, char_range))
+        }
+
+        return None;
+    }
+}
+
+pub struct LineIterator<'a> {
+    range:  Range<CharIndex>,
+    clump:  Option<Range<CharIndex>>,
+    slices: SliceIterator<'a>,
+}
+
+impl<'a> Iterator<Range<CharIndex>> for LineIterator<'a> {
+    fn next(&mut self) -> Option<Range<CharIndex>> {
+        // Loop until we hit whitespace and are in a clump.
+        loop {
+            match self.slices.next() {
+                Some((glyphs, offset, slice_range)) => {
+                    match (glyphs.is_whitespace(), self.clump) {
+                        (false, Some(ref mut c))  => {
+                            c.extend_by(slice_range.length());
+                        }
+                        (false, None) => {
+                            let mut c = slice_range;
+                            c.shift_by(offset);
+                            self.clump = Some(c);
+                        }
+                        (true, None)    => { /* chomp whitespace */ }
+                        (true, Some(c)) => {
+                            self.clump = None;
+                            // The final whitespace clump is not included.
+                            return Some(c);
+                        }
+                    }
+                },
+                None => {
+                    // flush any remaining chars as a line
+                    if self.clump.is_some() {
+                        let mut c = self.clump.take_unwrap();
+                        c.extend_to(self.range.end());
+                        return Some(c);
+                    } else {
+                        return None;
+                    }
+                }
+            }
+        }
+    }
+}
+
+impl<'a> TextRun {
+    pub fn new(font: &mut Font, text: String) -> TextRun {
+        let glyphs = TextRun::break_and_shape(font, text.as_slice());
+        let run = TextRun {
+            text: Arc::new(text),
+            font_metrics: font.metrics.clone(),
+            font_template: font.handle.get_template(),
+            pt_size: font.pt_size,
+            glyphs: Arc::new(glyphs),
+        };
+        return run;
+    }
+
+    pub fn break_and_shape(font: &mut Font, text: &str) -> Vec<GlyphRun> {
+        // TODO(Issue #230): do a better job. See Gecko's LineBreaker.
+        let mut glyphs = vec!();
+        let (mut byte_i, mut char_i) = (0u, CharIndex(0));
+        let mut cur_slice_is_whitespace = false;
+        let (mut byte_last_boundary, mut char_last_boundary) = (0, CharIndex(0));
+        while byte_i < text.len() {
+            let range = text.char_range_at(byte_i);
+            let ch = range.ch;
+            let next = range.next;
+
+            // Slices alternate between whitespace and non-whitespace,
+            // representing line break opportunities.
+            let can_break_before = if cur_slice_is_whitespace {
+                match ch {
+                    ' ' | '\t' | '\n' => false,
+                    _ => {
+                        cur_slice_is_whitespace = false;
+                        true
+                    }
+                }
+            } else {
+                match ch {
+                    ' ' | '\t' | '\n' => {
+                        cur_slice_is_whitespace = true;
+                        true
+                    },
+                    _ => false
+                }
+            };
+
+            // Create a glyph store for this slice if it's nonempty.
+            if can_break_before && byte_i > byte_last_boundary {
+                let slice = text.slice(byte_last_boundary, byte_i).to_string();
+                debug!("creating glyph store for slice {} (ws? {}), {} - {} in run {}",
+                        slice, !cur_slice_is_whitespace, byte_last_boundary, byte_i, text);
+                glyphs.push(GlyphRun {
+                    glyph_store: font.shape_text(slice, !cur_slice_is_whitespace),
+                    range: Range::new(char_last_boundary, char_i - char_last_boundary),
+                });
+                byte_last_boundary = byte_i;
+                char_last_boundary = char_i;
+            }
+
+            byte_i = next;
+            char_i = char_i + CharIndex(1);
+        }
+
+        // Create a glyph store for the final slice if it's nonempty.
+        if byte_i > byte_last_boundary {
+            let slice = text.slice_from(byte_last_boundary).to_string();
+            debug!("creating glyph store for final slice {} (ws? {}), {} - {} in run {}",
+                slice, cur_slice_is_whitespace, byte_last_boundary, text.len(), text);
+            glyphs.push(GlyphRun {
+                glyph_store: font.shape_text(slice, cur_slice_is_whitespace),
+                range: Range::new(char_last_boundary, char_i - char_last_boundary),
+            });
+        }
+
+        glyphs
+    }
+
+    pub fn char_len(&self) -> CharIndex {
+        match self.glyphs.last() {
+            None => CharIndex(0),
+            Some(ref glyph_run) => glyph_run.range.end(),
+        }
+    }
+
+    pub fn glyphs(&'a self) -> &'a Vec<GlyphRun> {
+        &*self.glyphs
+    }
+
+    pub fn range_is_trimmable_whitespace(&self, range: &Range<CharIndex>) -> bool {
+        self.iter_slices_for_range(range).all(|(slice_glyphs, _, _)| {
+            slice_glyphs.is_whitespace()
+        })
+    }
+
+    pub fn ascent(&self) -> Au {
+        self.font_metrics.ascent
+    }
+
+    pub fn descent(&self) -> Au {
+        self.font_metrics.descent
+    }
+
+    pub fn advance_for_range(&self, range: &Range<CharIndex>) -> Au {
+        // TODO(Issue #199): alter advance direction for RTL
+        // TODO(Issue #98): using inter-char and inter-word spacing settings  when measuring text
+        self.iter_slices_for_range(range)
+            .fold(Au(0), |advance, (glyphs, _, slice_range)| {
+                advance + glyphs.advance_for_char_range(&slice_range)
+            })
+    }
+
+    pub fn metrics_for_range(&self, range: &Range<CharIndex>) -> RunMetrics {
+        RunMetrics::new(self.advance_for_range(range),
+                        self.font_metrics.ascent,
+                        self.font_metrics.descent)
+    }
+
+    pub fn metrics_for_slice(&self, glyphs: &GlyphStore, slice_range: &Range<CharIndex>) -> RunMetrics {
+        RunMetrics::new(glyphs.advance_for_char_range(slice_range),
+                        self.font_metrics.ascent,
+                        self.font_metrics.descent)
+    }
+
+    pub fn min_width_for_range(&self, range: &Range<CharIndex>) -> Au {
+        debug!("iterating outer range {:?}", range);
+        self.iter_slices_for_range(range).fold(Au(0), |max_piece_width, (_, offset, slice_range)| {
+            debug!("iterated on {:?}[{:?}]", offset, slice_range);
+            Au::max(max_piece_width, self.advance_for_range(&slice_range))
+        })
+    }
+
+    /// Returns the index of the first glyph run containing the given character index.
+    fn index_of_first_glyph_run_containing(&self, index: CharIndex) -> Option<uint> {
+        self.glyphs.as_slice().binary_search_index_by(&index, CharIndexComparator)
+    }
+
+    pub fn iter_slices_for_range(&'a self, range: &Range<CharIndex>) -> SliceIterator<'a> {
+        let index = match self.index_of_first_glyph_run_containing(range.begin()) {
+            None => self.glyphs.len(),
+            Some(index) => index,
+        };
+        SliceIterator {
+            glyph_iter: self.glyphs.slice_from(index).iter(),
+            range:      *range,
+        }
+    }
+
+    pub fn iter_natural_lines_for_range(&'a self, range: &Range<CharIndex>) -> LineIterator<'a> {
+        LineIterator {
+            range:  *range,
+            clump:  None,
+            slices: self.iter_slices_for_range(range),
+        }
+    }
+}

components/gfx/text/util.rs

@@ -0,0 +1,285 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+use text::glyph::CharIndex;
+
+#[deriving(PartialEq)]
+pub enum CompressionMode {
+    CompressNone,
+    CompressWhitespace,
+    CompressWhitespaceNewline,
+    DiscardNewline
+}
+
+// ported from Gecko's nsTextFrameUtils::TransformText.
+//
+// High level TODOs:
+//
+// * Issue #113: consider incoming text state (arabic, etc)
+//               and propogate outgoing text state (dual of above)
+//
+// * Issue #114: record skipped and kept chars for mapping original to new text
+//
+// * Untracked: various edge cases for bidi, CJK, etc.
+pub fn transform_text(text: &str, mode: CompressionMode,
+                      incoming_whitespace: bool,
+                      new_line_pos: &mut Vec<CharIndex>) -> (String, bool) {
+    let mut out_str = String::new();
+    let out_whitespace = match mode {
+        CompressNone | DiscardNewline => {
+            let mut new_line_index = CharIndex(0);
+            for ch in text.chars() {
+                if is_discardable_char(ch, mode) {
+                    // TODO: record skipped char
+                } else {
+                    // TODO: record kept char
+                    if ch == '\t' {
+                        // TODO: set "has tab" flag
+                    } else if ch == '\n' {
+                        // Save new-line's position for line-break
+                        // This value is relative(not absolute)
+                        new_line_pos.push(new_line_index);
+                        new_line_index = CharIndex(0);
+                    }
+
+                    if ch != '\n' {
+                        new_line_index = new_line_index + CharIndex(1);
+                    }
+                    out_str.push_char(ch);
+                }
+            }
+            text.len() > 0 && is_in_whitespace(text.char_at_reverse(0), mode)
+        },
+
+        CompressWhitespace | CompressWhitespaceNewline => {
+            let mut in_whitespace: bool = incoming_whitespace;
+            for ch in text.chars() {
+                // TODO: discard newlines between CJK chars
+                let mut next_in_whitespace: bool = is_in_whitespace(ch, mode);
+
+                if !next_in_whitespace {
+                    if is_always_discardable_char(ch) {
+                        // revert whitespace setting, since this char was discarded
+                        next_in_whitespace = in_whitespace;
+                        // TODO: record skipped char
+                    } else {
+                        // TODO: record kept char
+                        out_str.push_char(ch);
+                    }
+                } else { /* next_in_whitespace; possibly add a space char */
+                    if in_whitespace {
+                        // TODO: record skipped char
+                    } else {
+                        // TODO: record kept char
+                        out_str.push_char(' ');
+                    }
+                }
+                // save whitespace context for next char
+                in_whitespace = next_in_whitespace;
+            } /* /for str::each_char */
+            in_whitespace
+        }
+    };
+
+    return (out_str.into_string(), out_whitespace);
+
+    fn is_in_whitespace(ch: char, mode: CompressionMode) -> bool {
+        match (ch, mode) {
+            (' ', _)  => true,
+            ('\t', _) => true,
+            ('\n', CompressWhitespaceNewline) => true,
+            (_, _)    => false
+        }
+    }
+
+    fn is_discardable_char(ch: char, mode: CompressionMode) -> bool {
+        if is_always_discardable_char(ch) {
+            return true;
+        }
+        match mode {
+            DiscardNewline | CompressWhitespaceNewline => ch == '\n',
+            _ => false
+        }
+    }
+
+    fn is_always_discardable_char(_ch: char) -> bool {
+        // TODO: check for bidi control chars, soft hyphens.
+        false
+    }
+}
+
+pub fn float_to_fixed(before: int, f: f64) -> i32 {
+    (1i32 << before as uint) * (f as i32)
+}
+
+pub fn fixed_to_float(before: int, f: i32) -> f64 {
+    f as f64 * 1.0f64 / ((1i32 << before as uint) as f64)
+}
+
+pub fn fixed_to_rounded_int(before: int, f: i32) -> int {
+    let half = 1i32 << (before-1) as uint;
+    if f > 0i32 {
+        ((half + f) >> before as uint) as int
+    } else {
+       -((half - f) >> before as uint) as int
+    }
+}
+
+/* Generate a 32-bit TrueType tag from its 4 characters */
+pub fn true_type_tag(a: char, b: char, c: char, d: char) -> u32 {
+    let a = a as u32;
+    let b = b as u32;
+    let c = c as u32;
+    let d = d as u32;
+    (a << 24 | b << 16 | c << 8 | d) as u32
+}
+
+#[test]
+fn test_true_type_tag() {
+    assert_eq!(true_type_tag('c', 'm', 'a', 'p'), 0x_63_6D_61_70_u32);
+}
+
+#[test]
+fn test_transform_compress_none() {
+    let test_strs = vec!(
+        "  foo bar",
+        "foo bar  ",
+        "foo\n bar",
+        "foo \nbar",
+        "  foo  bar  \nbaz",
+        "foo bar baz",
+        "foobarbaz\n\n"
+    );
+    let mode = CompressNone;
+
+    for test in test_strs.iter() {
+        let mut new_line_pos = vec!();
+        let (trimmed_str, _out) = transform_text(*test, mode, true, &mut new_line_pos);
+        assert_eq!(trimmed_str.as_slice(), *test)
+    }
+}
+
+#[test]
+fn test_transform_discard_newline() {
+    let test_strs = vec!(
+        "  foo bar",
+        "foo bar  ",
+        "foo\n bar",
+        "foo \nbar",
+        "  foo  bar  \nbaz",
+        "foo bar baz",
+        "foobarbaz\n\n"
+    );
+
+    let oracle_strs = vec!(
+        "  foo bar",
+        "foo bar  ",
+        "foo bar",
+        "foo bar",
+        "  foo  bar  baz",
+        "foo bar baz",
+        "foobarbaz"
+    );
+
+    assert_eq!(test_strs.len(), oracle_strs.len());
+    let mode = DiscardNewline;
+
+    for (test, oracle) in test_strs.iter().zip(oracle_strs.iter()) {
+        let mut new_line_pos = vec!();
+        let (trimmed_str, _out) = transform_text(*test, mode, true, &mut new_line_pos);
+        assert_eq!(trimmed_str.as_slice(), *oracle)
+    }
+}
+
+/* FIXME: Fix and re-enable
+#[test]
+fn test_transform_compress_whitespace() {
+    let  test_strs : ~[String] = ~["  foo bar".to_string(),
+                                 "foo bar  ".to_string(),
+                                 "foo\n bar".to_string(),
+                                 "foo \nbar".to_string(),
+                                 "  foo  bar  \nbaz".to_string(),
+                                 "foo bar baz".to_string(),
+                                 "foobarbaz\n\n".to_string()];
+
+    let oracle_strs : ~[String] = ~[" foo bar".to_string(),
+                                 "foo bar ".to_string(),
+                                 "foo\n bar".to_string(),
+                                 "foo \nbar".to_string(),
+                                 " foo bar \nbaz".to_string(),
+                                 "foo bar baz".to_string(),
+                                 "foobarbaz\n\n".to_string()];
+
+    assert_eq!(test_strs.len(), oracle_strs.len());
+    let mode = CompressWhitespace;
+
+    for i in range(0, test_strs.len()) {
+        let mut new_line_pos = ~[];
+        let (trimmed_str, _out) = transform_text(test_strs[i], mode, true, &mut new_line_pos);
+        assert_eq!(&trimmed_str, &oracle_strs[i])
+    }
+}
+
+#[test]
+fn test_transform_compress_whitespace_newline() {
+    let  test_strs : ~[String] = ~["  foo bar".to_string(),
+                                 "foo bar  ".to_string(),
+                                 "foo\n bar".to_string(),
+                                 "foo \nbar".to_string(),
+                                 "  foo  bar  \nbaz".to_string(),
+                                 "foo bar baz".to_string(),
+                                 "foobarbaz\n\n".to_string()];
+
+    let oracle_strs : ~[String] = ~["foo bar".to_string(),
+                                 "foo bar ".to_string(),
+                                 "foo bar".to_string(),
+                                 "foo bar".to_string(),
+                                 " foo bar baz".to_string(),
+                                 "foo bar baz".to_string(),
+                                 "foobarbaz ".to_string()];
+
+    assert_eq!(test_strs.len(), oracle_strs.len());
+    let mode = CompressWhitespaceNewline;
+
+    for i in range(0, test_strs.len()) {
+        let mut new_line_pos = ~[];
+        let (trimmed_str, _out) = transform_text(test_strs[i], mode, true, &mut new_line_pos);
+        assert_eq!(&trimmed_str, &oracle_strs[i])
+    }
+}
+*/
+
+#[test]
+fn test_transform_compress_whitespace_newline_no_incoming() {
+    let test_strs = vec!(
+        "  foo bar",
+        "\nfoo bar",
+        "foo bar  ",
+        "foo\n bar",
+        "foo \nbar",
+        "  foo  bar  \nbaz",
+        "foo bar baz",
+        "foobarbaz\n\n"
+    );
+
+    let oracle_strs = vec!(
+        " foo bar",
+        " foo bar",
+        "foo bar ",
+        "foo bar",
+        "foo bar",
+        " foo bar baz",
+        "foo bar baz",
+        "foobarbaz "
+    );
+
+    assert_eq!(test_strs.len(), oracle_strs.len());
+    let mode = CompressWhitespaceNewline;
+
+    for (test, oracle) in test_strs.iter().zip(oracle_strs.iter()) {
+        let mut new_line_pos = vec!();
+        let (trimmed_str, _out) = transform_text(*test, mode, false, &mut new_line_pos);
+        assert_eq!(trimmed_str.as_slice(), *oracle)
+    }
+}