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servo/components/layout/fragment.rs
Patrick Walton bb6f557276 layout: Rewrite text and inline fragment handling during flow 
construction to avoid cloning and moving flows so much.

Besides amounting to a 5%-10% win on a page with a lot of text, this
simplifies and refactors the text layout code.
2014-10-20 22:05:38 -07:00

1996 lines
89 KiB
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/* 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 `Fragment` type, which represents the leaves of the layout tree.
#![deny(unsafe_block)]
use css::node_style::StyledNode;
use construct::FlowConstructor;
use context::LayoutContext;
use floats::{ClearBoth, ClearLeft, ClearRight, ClearType};
use flow;
use flow::Flow;
use flow_ref::FlowRef;
use incremental::RestyleDamage;
use inline::{InlineFragmentContext, InlineMetrics};
use layout_debug;
use model::{Auto, IntrinsicISizes, IntrinsicISizesContribution, MaybeAuto, Specified, specified};
use model;
use text;
use util::{OpaqueNodeMethods, ToGfxColor};
use wrapper::{TLayoutNode, ThreadSafeLayoutNode};
use geom::{Point2D, Rect, Size2D, SideOffsets2D};
use geom::approxeq::ApproxEq;
use gfx::color::rgb;
use gfx::display_list::{BackgroundAndBorderLevel, BaseDisplayItem, BorderDisplayItem};
use gfx::display_list::{BorderDisplayItemClass, ContentStackingLevel, DisplayList};
use gfx::display_list::{ImageDisplayItem, ImageDisplayItemClass, LineDisplayItem};
use gfx::display_list::{LineDisplayItemClass, OpaqueNode, PseudoDisplayItemClass};
use gfx::display_list::{SidewaysLeft, SidewaysRight, SolidColorDisplayItem};
use gfx::display_list::{SolidColorDisplayItemClass, StackingLevel, TextDisplayItem};
use gfx::display_list::{TextDisplayItemClass, Upright};
use gfx::text::glyph::CharIndex;
use gfx::text::text_run::TextRun;
use script_traits::UntrustedNodeAddress;
use serialize::{Encodable, Encoder};
use servo_msg::constellation_msg::{ConstellationChan, FrameRectMsg, PipelineId, SubpageId};
use servo_net::image::holder::ImageHolder;
use servo_net::local_image_cache::LocalImageCache;
use servo_util::geometry::{Au, ZERO_RECT};
use servo_util::geometry;
use servo_util::logical_geometry::{LogicalRect, LogicalSize, LogicalMargin, WritingMode};
use servo_util::range::*;
use servo_util::smallvec::SmallVec;
use servo_util::str::is_whitespace;
use std::cmp::{max, min};
use std::fmt;
use std::from_str::FromStr;
use std::num::Zero;
use string_cache::Atom;
use style::{ComputedValues, TElement, TNode, cascade_anonymous, RGBA};
use style::computed_values::{LengthOrPercentage, LengthOrPercentageOrAuto};
use style::computed_values::{LengthOrPercentageOrNone};
use style::computed_values::{overflow, LPA_Auto, background_attachment};
use style::computed_values::{background_repeat, border_style, clear, position, text_align};
use style::computed_values::{text_decoration, vertical_align, visibility, white_space};
use sync::{Arc, Mutex};
use url::Url;
/// Fragments (`struct Fragment`) are the leaves of the layout tree. They cannot position
/// themselves. In general, fragments do not have a simple correspondence with CSS fragments in the
/// specification:
///
/// * Several fragments may correspond to the same CSS box or DOM node. For example, a CSS text box
/// broken across two lines is represented by two fragments.
///
/// * Some CSS fragments are not created at all, such as some anonymous block fragments induced by
/// inline fragments with block-level sibling fragments. In that case, Servo uses an `InlineFlow`
/// with `BlockFlow` siblings; the `InlineFlow` is block-level, but not a block container. It is
/// positioned as if it were a block fragment, but its children are positioned according to
/// inline flow.
///
/// A `GenericFragment` is an empty fragment that contributes only borders, margins, padding, and
/// backgrounds. It is analogous to a CSS nonreplaced content box.
///
/// A fragment's type influences how its styles are interpreted during layout. For example,
/// replaced content such as images are resized differently from tables, text, or other content.
/// Different types of fragments may also contain custom data; for example, text fragments contain
/// text.
///
/// FIXME(#2260, pcwalton): This can be slimmed down some.
#[deriving(Clone)]
pub struct Fragment {
/// An opaque reference to the DOM node that this `Fragment` originates from.
pub node: OpaqueNode,
/// The CSS style of this fragment.
pub style: Arc<ComputedValues>,
/// How damaged this fragment is since last reflow.
pub restyle_damage: RestyleDamage,
/// The position of this fragment relative to its owning flow.
/// The size includes padding and border, but not margin.
pub border_box: LogicalRect<Au>,
/// The sum of border and padding; i.e. the distance from the edge of the border box to the
/// content edge of the fragment.
pub border_padding: LogicalMargin<Au>,
/// The margin of the content box.
pub margin: LogicalMargin<Au>,
/// Info specific to the kind of fragment. Keep this enum small.
pub specific: SpecificFragmentInfo,
/// New-line chracter(\n)'s positions(relative, not absolute)
///
/// FIXME(#2260, pcwalton): This is very inefficient; remove.
pub new_line_pos: Vec<CharIndex>,
/// Holds the style context information for fragments
/// that are part of an inline formatting context.
pub inline_context: Option<InlineFragmentContext>,
/// A debug ID that is consistent for the life of
/// this fragment (via transform etc).
pub debug_id: uint,
}
impl<E, S: Encoder<E>> Encodable<S, E> for Fragment {
fn encode(&self, e: &mut S) -> Result<(), E> {
e.emit_struct("fragment", 0, |e| {
try!(e.emit_struct_field("id", 0, |e| self.debug_id().encode(e)))
try!(e.emit_struct_field("border_box", 1, |e| self.border_box.encode(e)))
e.emit_struct_field("margin", 2, |e| self.margin.encode(e))
})
}
}
/// Info specific to the kind of fragment. Keep this enum small.
#[deriving(Clone)]
pub enum SpecificFragmentInfo {
GenericFragment,
IframeFragment(IframeFragmentInfo),
ImageFragment(ImageFragmentInfo),
/// A hypothetical box (see CSS 2.1 § 10.3.7) for an absolutely-positioned block that was
/// declared with `display: inline;`.
InlineAbsoluteHypotheticalFragment(InlineAbsoluteHypotheticalFragmentInfo),
InlineBlockFragment(InlineBlockFragmentInfo),
InputFragment,
ScannedTextFragment(ScannedTextFragmentInfo),
TableFragment,
TableCellFragment,
TableColumnFragment(TableColumnFragmentInfo),
TableRowFragment,
TableWrapperFragment,
UnscannedTextFragment(UnscannedTextFragmentInfo),
}
impl SpecificFragmentInfo {
fn restyle_damage(&self) -> RestyleDamage {
let flow =
match *self {
IframeFragment(_)
| ImageFragment(_)
| InputFragment
| ScannedTextFragment(_)
| TableFragment
| TableCellFragment
| TableColumnFragment(_)
| TableRowFragment
| TableWrapperFragment
| UnscannedTextFragment(_)
| GenericFragment => return RestyleDamage::empty(),
InlineAbsoluteHypotheticalFragment(ref info) => &info.flow_ref,
InlineBlockFragment(ref info) => &info.flow_ref,
};
flow::base(flow.deref()).restyle_damage
}
pub fn get_type(&self) -> &'static str {
match *self {
GenericFragment => "GenericFragment",
IframeFragment(_) => "IframeFragment",
ImageFragment(_) => "ImageFragment",
InlineAbsoluteHypotheticalFragment(_) => "InlineAbsoluteHypotheticalFragment",
InlineBlockFragment(_) => "InlineBlockFragment",
InputFragment => "InputFragment",
ScannedTextFragment(_) => "ScannedTextFragment",
TableFragment => "TableFragment",
TableCellFragment => "TableCellFragment",
TableColumnFragment(_) => "TableColumnFragment",
TableRowFragment => "TableRowFragment",
TableWrapperFragment => "TableWrapperFragment",
UnscannedTextFragment(_) => "UnscannedTextFragment",
}
}
}
/// A hypothetical box (see CSS 2.1 § 10.3.7) for an absolutely-positioned block that was declared
/// with `display: inline;`.
///
/// FIXME(pcwalton): Stop leaking this `FlowRef` to layout; that is not memory safe because layout
/// can clone it.
#[deriving(Clone)]
pub struct InlineAbsoluteHypotheticalFragmentInfo {
pub flow_ref: FlowRef,
}
impl InlineAbsoluteHypotheticalFragmentInfo {
pub fn new(flow_ref: FlowRef) -> InlineAbsoluteHypotheticalFragmentInfo {
InlineAbsoluteHypotheticalFragmentInfo {
flow_ref: flow_ref,
}
}
}
/// A fragment that represents an inline-block element.
///
/// FIXME(pcwalton): Stop leaking this `FlowRef` to layout; that is not memory safe because layout
/// can clone it.
#[deriving(Clone)]
pub struct InlineBlockFragmentInfo {
pub flow_ref: FlowRef,
}
impl InlineBlockFragmentInfo {
pub fn new(flow_ref: FlowRef) -> InlineBlockFragmentInfo {
InlineBlockFragmentInfo {
flow_ref: flow_ref,
}
}
}
/// A fragment that represents a replaced content image and its accompanying borders, shadows, etc.
#[deriving(Clone)]
pub struct ImageFragmentInfo {
/// The image held within this fragment.
pub image: ImageHolder<UntrustedNodeAddress>,
pub for_node: UntrustedNodeAddress,
pub computed_inline_size: Option<Au>,
pub computed_block_size: Option<Au>,
pub dom_inline_size: Option<Au>,
pub dom_block_size: Option<Au>,
pub writing_mode_is_vertical: bool,
}
impl ImageFragmentInfo {
/// Creates a new image fragment from the given URL and local image cache.
///
/// FIXME(pcwalton): The fact that image fragments store the cache in the fragment makes little
/// sense to me.
pub fn new(node: &ThreadSafeLayoutNode,
image_url: Url,
local_image_cache: Arc<Mutex<LocalImageCache<UntrustedNodeAddress>>>)
-> ImageFragmentInfo {
fn convert_length(node: &ThreadSafeLayoutNode, name: &Atom) -> Option<Au> {
let element = node.as_element();
element.get_attr(&ns!(""), name).and_then(|string| {
let n: Option<int> = FromStr::from_str(string);
n
}).and_then(|pixels| Some(Au::from_px(pixels)))
}
let is_vertical = node.style().writing_mode.is_vertical();
let dom_width = convert_length(node, &atom!("width"));
let dom_height = convert_length(node, &atom!("height"));
let opaque_node: OpaqueNode = OpaqueNodeMethods::from_thread_safe_layout_node(node);
let untrusted_node: UntrustedNodeAddress = opaque_node.to_untrusted_node_address();
ImageFragmentInfo {
image: ImageHolder::new(image_url, local_image_cache),
for_node: untrusted_node,
computed_inline_size: None,
computed_block_size: None,
dom_inline_size: if is_vertical { dom_height } else { dom_width },
dom_block_size: if is_vertical { dom_width } else { dom_height },
writing_mode_is_vertical: is_vertical,
}
}
/// Returns the calculated inline-size of the image, accounting for the inline-size attribute.
pub fn computed_inline_size(&self) -> Au {
self.computed_inline_size.expect("image inline_size is not computed yet!")
}
/// Returns the calculated block-size of the image, accounting for the block-size attribute.
pub fn computed_block_size(&self) -> Au {
self.computed_block_size.expect("image block_size is not computed yet!")
}
/// Returns the original inline-size of the image.
pub fn image_inline_size(&mut self) -> Au {
let size = self.image.get_size(self.for_node).unwrap_or(Size2D::zero());
Au::from_px(if self.writing_mode_is_vertical { size.height } else { size.width })
}
/// Returns the original block-size of the image.
pub fn image_block_size(&mut self) -> Au {
let size = self.image.get_size(self.for_node).unwrap_or(Size2D::zero());
Au::from_px(if self.writing_mode_is_vertical { size.width } else { size.height })
}
// Return used value for inline-size or block-size.
//
// `dom_length`: inline-size or block-size as specified in the `img` tag.
// `style_length`: inline-size as given in the CSS
pub fn style_length(style_length: LengthOrPercentageOrAuto,
dom_length: Option<Au>,
container_inline_size: Au) -> MaybeAuto {
match (MaybeAuto::from_style(style_length,container_inline_size),dom_length) {
(Specified(length),_) => {
Specified(length)
},
(Auto,Some(length)) => {
Specified(length)
},
(Auto,None) => {
Auto
}
}
}
/// Clamp a value obtained from style_length, based on min / max lengths.
pub fn clamp_size(size: Au, min_size: LengthOrPercentage, max_size: LengthOrPercentageOrNone,
container_inline_size: Au) -> Au {
let min_size = model::specified(min_size, container_inline_size);
let max_size = model::specified_or_none(max_size, container_inline_size);
Au::max(min_size, match max_size {
None => size,
Some(max_size) => Au::min(size, max_size),
})
}
/// Tile an image
pub fn tile_image(position: &mut Au, size: &mut Au,
virtual_position: Au, image_size: u32) {
let image_size = image_size as int;
let delta_pixels = geometry::to_px(virtual_position - *position);
let tile_count = (delta_pixels + image_size - 1) / image_size;
let offset = Au::from_px(image_size * tile_count);
let new_position = virtual_position - offset;
*size = *position - new_position + *size;
*position = new_position;
}
}
/// A fragment that represents an inline frame (iframe). This stores the pipeline ID so that the size
/// of this iframe can be communicated via the constellation to the iframe's own layout task.
#[deriving(Clone)]
pub struct IframeFragmentInfo {
/// The pipeline ID of this iframe.
pub pipeline_id: PipelineId,
/// The subpage ID of this iframe.
pub subpage_id: SubpageId,
}
impl IframeFragmentInfo {
/// Creates the information specific to an iframe fragment.
pub fn new(node: &ThreadSafeLayoutNode) -> IframeFragmentInfo {
let (pipeline_id, subpage_id) = node.iframe_pipeline_and_subpage_ids();
IframeFragmentInfo {
pipeline_id: pipeline_id,
subpage_id: subpage_id,
}
}
}
/// A scanned text fragment represents a single run of text with a distinct style. A `TextFragment`
/// may be split into two or more fragments across line breaks. Several `TextFragment`s may
/// correspond to a single DOM text node. Split text fragments are implemented by referring to
/// subsets of a single `TextRun` object.
#[deriving(Clone)]
pub struct ScannedTextFragmentInfo {
/// The text run that this represents.
pub run: Arc<Box<TextRun>>,
/// The range within the above text run that this represents.
pub range: Range<CharIndex>,
/// The new_line_pos is eaten during line breaking. If we need to re-merge
/// fragments, it will have to be restored.
pub original_new_line_pos: Option<Vec<CharIndex>>,
/// The inline-size of the text fragment.
pub content_inline_size: Au,
}
impl ScannedTextFragmentInfo {
/// Creates the information specific to a scanned text fragment from a range and a text run.
pub fn new(run: Arc<Box<TextRun>>, range: Range<CharIndex>, content_inline_size: Au)
-> ScannedTextFragmentInfo {
ScannedTextFragmentInfo {
run: run,
range: range,
original_new_line_pos: None,
content_inline_size: content_inline_size,
}
}
}
#[deriving(Show)]
pub struct SplitInfo {
// TODO(bjz): this should only need to be a single character index, but both values are
// currently needed for splitting in the `inline::try_append_*` functions.
pub range: Range<CharIndex>,
pub inline_size: Au,
}
impl SplitInfo {
fn new(range: Range<CharIndex>, info: &ScannedTextFragmentInfo) -> SplitInfo {
SplitInfo {
range: range,
inline_size: info.run.advance_for_range(&range),
}
}
}
/// Data for an unscanned text fragment. Unscanned text fragments are the results of flow construction that
/// have not yet had their inline-size determined.
#[deriving(Clone)]
pub struct UnscannedTextFragmentInfo {
/// The text inside the fragment.
pub text: String,
}
impl UnscannedTextFragmentInfo {
/// Creates a new instance of `UnscannedTextFragmentInfo` from the given DOM node.
pub fn new(node: &ThreadSafeLayoutNode) -> UnscannedTextFragmentInfo {
// FIXME(pcwalton): Don't copy text; atomically reference count it instead.
UnscannedTextFragmentInfo {
text: node.text(),
}
}
/// Creates a new instance of `UnscannedTextFragmentInfo` from the given text.
#[inline]
pub fn from_text(text: String) -> UnscannedTextFragmentInfo {
UnscannedTextFragmentInfo {
text: text,
}
}
}
/// A fragment that represents a table column.
#[deriving(Clone)]
pub struct TableColumnFragmentInfo {
/// the number of columns a <col> element should span
pub span: Option<int>,
}
impl TableColumnFragmentInfo {
/// Create the information specific to an table column fragment.
pub fn new(node: &ThreadSafeLayoutNode) -> TableColumnFragmentInfo {
let span = {
let element = node.as_element();
element.get_attr(&ns!(""), &atom!("span")).and_then(|string| {
let n: Option<int> = FromStr::from_str(string);
n
})
};
TableColumnFragmentInfo {
span: span,
}
}
}
impl Fragment {
/// Constructs a new `Fragment` instance for the given node.
///
/// This does *not* construct the text for generated content. See comments in
/// `FlowConstructor::build_specific_fragment_info_for_node()` for more details.
///
/// Arguments:
///
/// * `constructor`: The flow constructor.
/// * `node`: The node to create a fragment for.
pub fn new(constructor: &mut FlowConstructor, node: &ThreadSafeLayoutNode) -> Fragment {
let style = node.style().clone();
let writing_mode = style.writing_mode;
Fragment {
node: OpaqueNodeMethods::from_thread_safe_layout_node(node),
style: style,
restyle_damage: node.restyle_damage(),
border_box: LogicalRect::zero(writing_mode),
border_padding: LogicalMargin::zero(writing_mode),
margin: LogicalMargin::zero(writing_mode),
specific: constructor.build_specific_fragment_info_for_node(node),
new_line_pos: vec!(),
inline_context: None,
debug_id: layout_debug::generate_unique_debug_id(),
}
}
/// Constructs a new `Fragment` instance from a specific info.
pub fn new_from_specific_info(node: &ThreadSafeLayoutNode, specific: SpecificFragmentInfo)
-> Fragment {
let style = node.style().clone();
let writing_mode = style.writing_mode;
Fragment {
node: OpaqueNodeMethods::from_thread_safe_layout_node(node),
style: style,
restyle_damage: node.restyle_damage(),
border_box: LogicalRect::zero(writing_mode),
border_padding: LogicalMargin::zero(writing_mode),
margin: LogicalMargin::zero(writing_mode),
specific: specific,
new_line_pos: vec!(),
inline_context: None,
debug_id: layout_debug::generate_unique_debug_id(),
}
}
/// Constructs a new `Fragment` instance for an anonymous table object.
pub fn new_anonymous_table_fragment(node: &ThreadSafeLayoutNode,
specific: SpecificFragmentInfo)
-> Fragment {
// CSS 2.1 § 17.2.1 This is for non-inherited properties on anonymous table fragments
// example:
//
// <div style="display: table">
// Foo
// </div>
//
// Anonymous table fragments, TableRowFragment and TableCellFragment, are generated around
// `Foo`, but they shouldn't inherit the border.
let node_style = cascade_anonymous(&**node.style());
let writing_mode = node_style.writing_mode;
Fragment {
node: OpaqueNodeMethods::from_thread_safe_layout_node(node),
style: Arc::new(node_style),
restyle_damage: node.restyle_damage(),
border_box: LogicalRect::zero(writing_mode),
border_padding: LogicalMargin::zero(writing_mode),
margin: LogicalMargin::zero(writing_mode),
specific: specific,
new_line_pos: vec!(),
inline_context: None,
debug_id: layout_debug::generate_unique_debug_id(),
}
}
/// Constructs a new `Fragment` instance from an opaque node.
pub fn from_opaque_node_and_style(node: OpaqueNode,
style: Arc<ComputedValues>,
restyle_damage: RestyleDamage,
specific: SpecificFragmentInfo)
-> Fragment {
let writing_mode = style.writing_mode;
Fragment {
node: node,
style: style,
restyle_damage: restyle_damage,
border_box: LogicalRect::zero(writing_mode),
border_padding: LogicalMargin::zero(writing_mode),
margin: LogicalMargin::zero(writing_mode),
specific: specific,
new_line_pos: vec!(),
inline_context: None,
debug_id: layout_debug::generate_unique_debug_id(),
}
}
pub fn reset_inline_sizes(&mut self) {
self.border_padding = LogicalMargin::zero(self.style.writing_mode);
self.margin = LogicalMargin::zero(self.style.writing_mode);
}
/// Saves the new_line_pos vector into a `ScannedTextFragment`. This will fail
/// if called on any other type of fragment.
pub fn save_new_line_pos(&mut self) {
match &mut self.specific {
&ScannedTextFragment(ref mut info) => {
if !self.new_line_pos.is_empty() {
info.original_new_line_pos = Some(self.new_line_pos.clone());
}
}
_ => {}
}
}
pub fn restore_new_line_pos(&mut self) {
match &mut self.specific {
&ScannedTextFragment(ref mut info) => {
match info.original_new_line_pos.take() {
None => {}
Some(new_line_pos) => self.new_line_pos = new_line_pos,
}
return
}
_ => {}
}
}
/// Returns a debug ID of this fragment. This ID should not be considered stable across
/// multiple layouts or fragment manipulations.
pub fn debug_id(&self) -> uint {
self.debug_id
}
/// Transforms this fragment into another fragment of the given type, with the given size,
/// preserving all the other data.
pub fn transform(&self, size: LogicalSize<Au>, mut info: ScannedTextFragmentInfo) -> Fragment {
let new_border_box =
LogicalRect::from_point_size(self.style.writing_mode, self.border_box.start, size);
info.content_inline_size = size.inline;
Fragment {
node: self.node,
style: self.style.clone(),
restyle_damage: RestyleDamage::all(),
border_box: new_border_box,
border_padding: self.border_padding,
margin: self.margin,
specific: ScannedTextFragment(info),
new_line_pos: self.new_line_pos.clone(),
inline_context: self.inline_context.clone(),
debug_id: self.debug_id,
}
}
pub fn restyle_damage(&self) -> RestyleDamage {
self.restyle_damage | self.specific.restyle_damage()
}
/// Adds a style to the inline context for this fragment. If the inline
/// context doesn't exist yet, it will be created.
pub fn add_inline_context_style(&mut self, style: Arc<ComputedValues>) {
if self.inline_context.is_none() {
self.inline_context = Some(InlineFragmentContext::new());
}
self.inline_context.as_mut().unwrap().styles.push(style.clone());
}
/// Determines which quantities (border/padding/margin/specified) should be included in the
/// intrinsic inline size of this fragment.
fn quantities_included_in_intrinsic_inline_size(&self)
-> QuantitiesIncludedInIntrinsicInlineSizes {
match self.specific {
GenericFragment | IframeFragment(_) | ImageFragment(_) | InlineBlockFragment(_) |
InputFragment => QuantitiesIncludedInIntrinsicInlineSizes::all(),
TableFragment | TableCellFragment => {
IntrinsicInlineSizeIncludesPadding |
IntrinsicInlineSizeIncludesBorder |
IntrinsicInlineSizeIncludesSpecified
}
TableWrapperFragment => {
IntrinsicInlineSizeIncludesMargins |
IntrinsicInlineSizeIncludesBorder |
IntrinsicInlineSizeIncludesSpecified
}
TableRowFragment => {
IntrinsicInlineSizeIncludesBorder |
IntrinsicInlineSizeIncludesSpecified
}
ScannedTextFragment(_) | TableColumnFragment(_) | UnscannedTextFragment(_) |
InlineAbsoluteHypotheticalFragment(_) => {
QuantitiesIncludedInIntrinsicInlineSizes::empty()
}
}
}
/// Returns the portion of the intrinsic inline-size that consists of borders, padding, and/or
/// margins.
///
/// FIXME(#2261, pcwalton): This won't work well for inlines: is this OK?
pub fn surrounding_intrinsic_inline_size(&self) -> Au {
let flags = self.quantities_included_in_intrinsic_inline_size();
let style = self.style();
// FIXME(pcwalton): Percentages should be relative to any definite size per CSS-SIZING.
// This will likely need to be done by pushing down definite sizes during selector
// cascading.
let margin = if flags.contains(IntrinsicInlineSizeIncludesMargins) {
let margin = style.logical_margin();
(MaybeAuto::from_style(margin.inline_start, Au(0)).specified_or_zero() +
MaybeAuto::from_style(margin.inline_end, Au(0)).specified_or_zero())
} else {
Au(0)
};
// FIXME(pcwalton): Percentages should be relative to any definite size per CSS-SIZING.
// This will likely need to be done by pushing down definite sizes during selector
// cascading.
let padding = if flags.contains(IntrinsicInlineSizeIncludesPadding) {
let padding = style.logical_padding();
(model::specified(padding.inline_start, Au(0)) +
model::specified(padding.inline_end, Au(0)))
} else {
Au(0)
};
let border = if flags.contains(IntrinsicInlineSizeIncludesBorder) {
self.border_width().inline_start_end()
} else {
Au(0)
};
margin + padding + border
}
/// Uses the style only to estimate the intrinsic inline-sizes. These may be modified for text
/// or replaced elements.
fn style_specified_intrinsic_inline_size(&self) -> IntrinsicISizesContribution {
let flags = self.quantities_included_in_intrinsic_inline_size();
let style = self.style();
let specified = if flags.contains(IntrinsicInlineSizeIncludesSpecified) {
MaybeAuto::from_style(style.content_inline_size(), Au(0)).specified_or_zero()
} else {
Au(0)
};
// FIXME(#2261, pcwalton): This won't work well for inlines: is this OK?
let surrounding_inline_size = self.surrounding_intrinsic_inline_size();
IntrinsicISizesContribution {
content_intrinsic_sizes: IntrinsicISizes {
minimum_inline_size: specified,
preferred_inline_size: specified,
},
surrounding_size: surrounding_inline_size,
}
}
pub fn calculate_line_height(&self, layout_context: &LayoutContext) -> Au {
let font_style = self.style.get_font();
let font_metrics = text::font_metrics_for_style(layout_context.font_context(), font_style);
text::line_height_from_style(&*self.style, &font_metrics)
}
/// Returns the sum of the inline-sizes of all the borders of this fragment. Note that this
/// can be expensive to compute, so if possible use the `border_padding` field instead.
#[inline]
pub fn border_width(&self) -> LogicalMargin<Au> {
let style_border_width = match self.specific {
ScannedTextFragment(_) => LogicalMargin::zero(self.style.writing_mode),
_ => self.style().logical_border_width(),
};
match self.inline_context {
None => style_border_width,
Some(ref inline_fragment_context) => {
inline_fragment_context.styles.iter().fold(style_border_width,
|acc, style| acc + style.logical_border_width())
}
}
}
/// Computes the margins in the inline direction from the containing block inline-size and the
/// style. After this call, the inline direction of the `margin` field will be correct.
///
/// Do not use this method if the inline direction margins are to be computed some other way
/// (for example, via constraint solving for blocks).
pub fn compute_inline_direction_margins(&mut self, containing_block_inline_size: Au) {
match self.specific {
TableFragment | TableCellFragment | TableRowFragment | TableColumnFragment(_) => {
self.margin.inline_start = Au(0);
self.margin.inline_end = Au(0)
}
_ => {
let margin = self.style().logical_margin();
self.margin.inline_start =
MaybeAuto::from_style(margin.inline_start, containing_block_inline_size)
.specified_or_zero();
self.margin.inline_end =
MaybeAuto::from_style(margin.inline_end, containing_block_inline_size)
.specified_or_zero();
}
}
}
/// Computes the margins in the block direction from the containing block inline-size and the
/// style. After this call, the block direction of the `margin` field will be correct.
///
/// Do not use this method if the block direction margins are to be computed some other way
/// (for example, via constraint solving for absolutely-positioned flows).
pub fn compute_block_direction_margins(&mut self, containing_block_inline_size: Au) {
match self.specific {
TableFragment | TableCellFragment | TableRowFragment | TableColumnFragment(_) => {
self.margin.block_start = Au(0);
self.margin.block_end = Au(0)
}
_ => {
// NB: Percentages are relative to containing block inline-size (not block-size)
// per CSS 2.1.
let margin = self.style().logical_margin();
self.margin.block_start =
MaybeAuto::from_style(margin.block_start, containing_block_inline_size)
.specified_or_zero();
self.margin.block_end =
MaybeAuto::from_style(margin.block_end, containing_block_inline_size)
.specified_or_zero();
}
}
}
/// Computes the border and padding in both inline and block directions from the containing
/// block inline-size and the style. After this call, the `border_padding` field will be
/// correct.
pub fn compute_border_and_padding(&mut self, containing_block_inline_size: Au) {
// Compute border.
let border = self.border_width();
// Compute padding.
let padding = match self.specific {
TableColumnFragment(_) | TableRowFragment |
TableWrapperFragment => LogicalMargin::zero(self.style.writing_mode),
_ => {
let style_padding = match self.specific {
ScannedTextFragment(_) => LogicalMargin::zero(self.style.writing_mode),
_ => model::padding_from_style(self.style(), containing_block_inline_size),
};
match self.inline_context {
None => style_padding,
Some(ref inline_fragment_context) => {
inline_fragment_context.styles.iter().fold(style_padding,
|acc, style| acc + model::padding_from_style(&**style, Au(0)))
}
}
}
};
self.border_padding = border + padding
}
// Return offset from original position because of `position: relative`.
pub fn relative_position(&self,
containing_block_size: &LogicalSize<Au>)
-> LogicalSize<Au> {
fn from_style(style: &ComputedValues, container_size: &LogicalSize<Au>)
-> LogicalSize<Au> {
let offsets = style.logical_position();
let offset_i = if offsets.inline_start != LPA_Auto {
MaybeAuto::from_style(offsets.inline_start, container_size.inline).specified_or_zero()
} else {
-MaybeAuto::from_style(offsets.inline_end, container_size.inline).specified_or_zero()
};
let offset_b = if offsets.block_start != LPA_Auto {
MaybeAuto::from_style(offsets.block_start, container_size.inline).specified_or_zero()
} else {
-MaybeAuto::from_style(offsets.block_end, container_size.inline).specified_or_zero()
};
LogicalSize::new(style.writing_mode, offset_i, offset_b)
}
// Go over the ancestor fragments and add all relative offsets (if any).
let mut rel_pos = if self.style().get_box().position == position::relative {
from_style(self.style(), containing_block_size)
} else {
LogicalSize::zero(self.style.writing_mode)
};
match self.inline_context {
None => {}
Some(ref inline_fragment_context) => {
for style in inline_fragment_context.styles.iter() {
if style.get_box().position == position::relative {
rel_pos = rel_pos + from_style(&**style, containing_block_size);
}
}
},
}
rel_pos
}
/// Always inline for SCCP.
///
/// FIXME(pcwalton): Just replace with the clear type from the style module for speed?
#[inline(always)]
pub fn clear(&self) -> Option<ClearType> {
let style = self.style();
match style.get_box().clear {
clear::none => None,
clear::left => Some(ClearLeft),
clear::right => Some(ClearRight),
clear::both => Some(ClearBoth),
}
}
#[inline(always)]
pub fn style<'a>(&'a self) -> &'a ComputedValues {
&*self.style
}
/// Returns the text alignment of the computed style of the nearest ancestor-or-self `Element`
/// node.
pub fn text_align(&self) -> text_align::T {
self.style().get_inheritedtext().text_align
}
pub fn vertical_align(&self) -> vertical_align::T {
self.style().get_box().vertical_align
}
pub fn white_space(&self) -> white_space::T {
self.style().get_inheritedtext().white_space
}
/// Returns the text decoration of this fragment, according to the style of the nearest ancestor
/// element.
///
/// NB: This may not be the actual text decoration, because of the override rules specified in
/// CSS 2.1 § 16.3.1. Unfortunately, computing this properly doesn't really fit into Servo's
/// model. Therefore, this is a best lower bound approximation, but the end result may actually
/// have the various decoration flags turned on afterward.
pub fn text_decoration(&self) -> text_decoration::T {
self.style().get_text().text_decoration
}
/// Returns the inline-start offset from margin edge to content edge.
///
/// FIXME(#2262, pcwalton): I think this method is pretty bogus, because it won't work for
/// inlines.
pub fn inline_start_offset(&self) -> Au {
match self.specific {
TableWrapperFragment => self.margin.inline_start,
TableFragment | TableCellFragment | TableRowFragment => self.border_padding.inline_start,
TableColumnFragment(_) => Au(0),
_ => self.margin.inline_start + self.border_padding.inline_start,
}
}
/// Returns true if this element can be split. This is true for text fragments.
pub fn can_split(&self) -> bool {
self.is_scanned_text_fragment()
}
/// Returns true if and only if this is a scanned text fragment.
fn is_scanned_text_fragment(&self) -> bool {
match self.specific {
ScannedTextFragment(..) => true,
_ => false,
}
}
/// Adds the display items necessary to paint the background of this fragment to the display
/// list if necessary.
pub fn build_display_list_for_background_if_applicable(&self,
style: &ComputedValues,
list: &mut DisplayList,
layout_context: &LayoutContext,
level: StackingLevel,
absolute_bounds: &Rect<Au>,
clip_rect: &Rect<Au>) {
// FIXME: This causes a lot of background colors to be displayed when they are clearly not
// needed. We could use display list optimization to clean this up, but it still seems
// inefficient. What we really want is something like "nearest ancestor element that
// doesn't have a fragment".
let background_color = style.resolve_color(style.get_background().background_color);
if !background_color.alpha.approx_eq(&0.0) {
let display_item = box SolidColorDisplayItem {
base: BaseDisplayItem::new(*absolute_bounds, self.node, level, *clip_rect),
color: background_color.to_gfx_color(),
};
list.push(SolidColorDisplayItemClass(display_item))
}
// The background image is painted on top of the background color.
// Implements background image, per spec:
// http://www.w3.org/TR/CSS21/colors.html#background
let background = style.get_background();
let image_url = match background.background_image {
None => return,
Some(ref image_url) => image_url,
};
let mut holder = ImageHolder::new(image_url.clone(), layout_context.shared.image_cache.clone());
let image = match holder.get_image(self.node.to_untrusted_node_address()) {
None => {
// No image data at all? Do nothing.
//
// TODO: Add some kind of placeholder background image.
debug!("(building display list) no background image :(");
return
}
Some(image) => image,
};
debug!("(building display list) building background image");
let image_width = Au::from_px(image.width as int);
let image_height = Au::from_px(image.height as int);
let mut bounds = *absolute_bounds;
// Clip.
//
// TODO: Check the bounds to see if a clip item is actually required.
let clip_rect = clip_rect.intersection(&bounds).unwrap_or(ZERO_RECT);
// Use background-attachment to get the initial virtual origin
let (virtual_origin_x, virtual_origin_y) = match background.background_attachment {
background_attachment::scroll => {
(absolute_bounds.origin.x, absolute_bounds.origin.y)
}
background_attachment::fixed => {
(Au(0), Au(0))
}
};
// Use background-position to get the offset
let horizontal_position = model::specified(background.background_position.horizontal,
bounds.size.width - image_width);
let vertical_position = model::specified(background.background_position.vertical,
bounds.size.height - image_height);
let abs_x = virtual_origin_x + horizontal_position;
let abs_y = virtual_origin_y + vertical_position;
// Adjust origin and size based on background-repeat
match background.background_repeat {
background_repeat::no_repeat => {
bounds.origin.x = abs_x;
bounds.origin.y = abs_y;
bounds.size.width = image_width;
bounds.size.height = image_height;
}
background_repeat::repeat_x => {
bounds.origin.y = abs_y;
bounds.size.height = image_height;
ImageFragmentInfo::tile_image(&mut bounds.origin.x, &mut bounds.size.width,
abs_x, image.width);
}
background_repeat::repeat_y => {
bounds.origin.x = abs_x;
bounds.size.width = image_width;
ImageFragmentInfo::tile_image(&mut bounds.origin.y, &mut bounds.size.height,
abs_y, image.height);
}
background_repeat::repeat => {
ImageFragmentInfo::tile_image(&mut bounds.origin.x, &mut bounds.size.width,
abs_x, image.width);
ImageFragmentInfo::tile_image(&mut bounds.origin.y, &mut bounds.size.height,
abs_y, image.height);
}
};
// Create the image display item.
let image_display_item = ImageDisplayItemClass(box ImageDisplayItem {
base: BaseDisplayItem::new(bounds, self.node, level, clip_rect),
image: image.clone(),
stretch_size: Size2D(Au::from_px(image.width as int),
Au::from_px(image.height as int)),
});
list.push(image_display_item)
}
/// Adds the display items necessary to paint the borders of this fragment to a display list if
/// necessary.
pub fn build_display_list_for_borders_if_applicable(&self,
style: &ComputedValues,
list: &mut DisplayList,
abs_bounds: &Rect<Au>,
level: StackingLevel,
clip_rect: &Rect<Au>) {
let border = style.logical_border_width();
if border.is_zero() {
return
}
let top_color = style.resolve_color(style.get_border().border_top_color);
let right_color = style.resolve_color(style.get_border().border_right_color);
let bottom_color = style.resolve_color(style.get_border().border_bottom_color);
let left_color = style.resolve_color(style.get_border().border_left_color);
// Append the border to the display list.
let border_display_item = box BorderDisplayItem {
base: BaseDisplayItem::new(*abs_bounds, self.node, level, *clip_rect),
border: border.to_physical(style.writing_mode),
color: SideOffsets2D::new(top_color.to_gfx_color(),
right_color.to_gfx_color(),
bottom_color.to_gfx_color(),
left_color.to_gfx_color()),
style: SideOffsets2D::new(style.get_border().border_top_style,
style.get_border().border_right_style,
style.get_border().border_bottom_style,
style.get_border().border_left_style)
};
list.push(BorderDisplayItemClass(border_display_item))
}
fn build_debug_borders_around_text_fragments(&self,
display_list: &mut DisplayList,
flow_origin: Point2D<Au>,
text_fragment: &ScannedTextFragmentInfo,
clip_rect: &Rect<Au>) {
// FIXME(#2795): Get the real container size
let container_size = Size2D::zero();
// Fragment position wrt to the owning flow.
let fragment_bounds = self.border_box.to_physical(self.style.writing_mode, container_size);
let absolute_fragment_bounds = Rect(
fragment_bounds.origin + flow_origin,
fragment_bounds.size);
// Compute the text fragment bounds and draw a border surrounding them.
let border_display_item = box BorderDisplayItem {
base: BaseDisplayItem::new(absolute_fragment_bounds,
self.node,
ContentStackingLevel,
*clip_rect),
border: SideOffsets2D::new_all_same(Au::from_px(1)),
color: SideOffsets2D::new_all_same(rgb(0, 0, 200)),
style: SideOffsets2D::new_all_same(border_style::solid)
};
display_list.push(BorderDisplayItemClass(border_display_item));
// Draw a rectangle representing the baselines.
let ascent = text_fragment.run.ascent();
let mut baseline = self.border_box.clone();
baseline.start.b = baseline.start.b + ascent;
baseline.size.block = Au(0);
let mut baseline = baseline.to_physical(self.style.writing_mode, container_size);
baseline.origin = baseline.origin + flow_origin;
let line_display_item = box LineDisplayItem {
base: BaseDisplayItem::new(baseline, self.node, ContentStackingLevel, *clip_rect),
color: rgb(0, 200, 0),
style: border_style::dashed,
};
display_list.push(LineDisplayItemClass(line_display_item));
}
fn build_debug_borders_around_fragment(&self,
display_list: &mut DisplayList,
flow_origin: Point2D<Au>,
clip_rect: &Rect<Au>) {
// FIXME(#2795): Get the real container size
let container_size = Size2D::zero();
// Fragment position wrt to the owning flow.
let fragment_bounds = self.border_box.to_physical(self.style.writing_mode, container_size);
let absolute_fragment_bounds = Rect(
fragment_bounds.origin + flow_origin,
fragment_bounds.size);
// This prints a debug border around the border of this fragment.
let border_display_item = box BorderDisplayItem {
base: BaseDisplayItem::new(absolute_fragment_bounds,
self.node,
ContentStackingLevel,
*clip_rect),
border: SideOffsets2D::new_all_same(Au::from_px(1)),
color: SideOffsets2D::new_all_same(rgb(0, 0, 200)),
style: SideOffsets2D::new_all_same(border_style::solid)
};
display_list.push(BorderDisplayItemClass(border_display_item))
}
/// Adds the display items for this fragment to the given stacking context.
///
/// Arguments:
///
/// * `display_list`: The unflattened display list to add display items to.
/// * `layout_context`: The layout context.
/// * `dirty`: The dirty rectangle in the coordinate system of the owning flow.
/// * `flow_origin`: Position of the origin of the owning flow wrt the display list root flow.
/// * `clip_rect`: The rectangle to clip the display items to.
pub fn build_display_list(&mut self,
display_list: &mut DisplayList,
layout_context: &LayoutContext,
flow_origin: Point2D<Au>,
background_and_border_level: BackgroundAndBorderLevel,
clip_rect: &Rect<Au>) {
// FIXME(#2795): Get the real container size
let container_size = Size2D::zero();
let rect_to_absolute = |writing_mode: WritingMode, logical_rect: LogicalRect<Au>| {
let physical_rect = logical_rect.to_physical(writing_mode, container_size);
Rect(physical_rect.origin + flow_origin, physical_rect.size)
};
// Fragment position wrt to the owning flow.
let absolute_fragment_bounds = rect_to_absolute(self.style.writing_mode, self.border_box);
debug!("Fragment::build_display_list at rel={}, abs={}: {}",
self.border_box,
absolute_fragment_bounds,
self);
debug!("Fragment::build_display_list: dirty={}, flow_origin={}",
layout_context.shared.dirty,
flow_origin);
if self.style().get_inheritedbox().visibility != visibility::visible {
return
}
if !absolute_fragment_bounds.intersects(&layout_context.shared.dirty) {
debug!("Fragment::build_display_list: Did not intersect...");
return
}
debug!("Fragment::build_display_list: intersected. Adding display item...");
if self.is_primary_fragment() {
let level =
StackingLevel::from_background_and_border_level(background_and_border_level);
// Add a pseudo-display item for content box queries. This is a very bogus thing to do.
let base_display_item = box BaseDisplayItem::new(absolute_fragment_bounds,
self.node,
level,
*clip_rect);
display_list.push(PseudoDisplayItemClass(base_display_item));
// Add the background to the list, if applicable.
match self.inline_context {
Some(ref inline_context) => {
for style in inline_context.styles.iter().rev() {
self.build_display_list_for_background_if_applicable(
&**style,
display_list,
layout_context,
level,
&absolute_fragment_bounds,
clip_rect);
}
}
None => {}
}
match self.specific {
ScannedTextFragment(_) => {},
_ => {
self.build_display_list_for_background_if_applicable(
&*self.style,
display_list,
layout_context,
level,
&absolute_fragment_bounds,
clip_rect);
}
}
// Add a border, if applicable.
//
// TODO: Outlines.
match self.inline_context {
Some(ref inline_context) => {
for style in inline_context.styles.iter().rev() {
self.build_display_list_for_borders_if_applicable(
&**style,
display_list,
&absolute_fragment_bounds,
level,
clip_rect);
}
}
None => {}
}
match self.specific {
ScannedTextFragment(_) => {},
_ => {
self.build_display_list_for_borders_if_applicable(
&*self.style,
display_list,
&absolute_fragment_bounds,
level,
clip_rect);
}
}
}
let content_box = self.content_box();
let absolute_content_box = rect_to_absolute(self.style.writing_mode, content_box);
// Create special per-fragment-type display items.
match self.specific {
UnscannedTextFragment(_) => fail!("Shouldn't see unscanned fragments here."),
TableColumnFragment(_) => fail!("Shouldn't see table column fragments here."),
ScannedTextFragment(ref text_fragment) => {
// Create the text display item.
let orientation = if self.style.writing_mode.is_vertical() {
if self.style.writing_mode.is_sideways_left() {
SidewaysLeft
} else {
SidewaysRight
}
} else {
Upright
};
let metrics = &text_fragment.run.font_metrics;
let baseline_origin ={
let mut tmp = content_box.start;
tmp.b = tmp.b + metrics.ascent;
tmp.to_physical(self.style.writing_mode, container_size) + flow_origin
};
let text_display_item = box TextDisplayItem {
base: BaseDisplayItem::new(absolute_content_box,
self.node,
ContentStackingLevel,
*clip_rect),
text_run: text_fragment.run.clone(),
range: text_fragment.range,
text_color: self.style().get_color().color.to_gfx_color(),
orientation: orientation,
baseline_origin: baseline_origin,
};
display_list.push(TextDisplayItemClass(text_display_item));
// Create display items for text decoration
{
let line = |maybe_color: Option<RGBA>, rect: || -> LogicalRect<Au>| {
match maybe_color {
None => {},
Some(color) => {
display_list.push(SolidColorDisplayItemClass(
box SolidColorDisplayItem {
base: BaseDisplayItem::new(
rect_to_absolute(
self.style.writing_mode,
rect()),
self.node,
ContentStackingLevel,
*clip_rect),
color: color.to_gfx_color(),
}));
}
}
};
let text_decorations =
self.style().get_inheritedtext()._servo_text_decorations_in_effect;
line(text_decorations.underline, || {
let mut rect = content_box.clone();
rect.start.b = rect.start.b + metrics.ascent - metrics.underline_offset;
rect.size.block = metrics.underline_size;
rect
});
line(text_decorations.overline, || {
let mut rect = content_box.clone();
rect.size.block = metrics.underline_size;
rect
});
line(text_decorations.line_through, || {
let mut rect = content_box.clone();
rect.start.b = rect.start.b + metrics.ascent - metrics.strikeout_offset;
rect.size.block = metrics.strikeout_size;
rect
});
}
// Draw debug frames for text bounds.
//
// FIXME(#2263, pcwalton): This is a bit of an abuse of the logging infrastructure.
// We should have a real `SERVO_DEBUG` system.
debug!("{:?}", self.build_debug_borders_around_text_fragments(display_list,
flow_origin,
text_fragment,
clip_rect))
}
GenericFragment | IframeFragment(..) | TableFragment | TableCellFragment |
TableRowFragment | TableWrapperFragment | InlineBlockFragment(_) | InputFragment |
InlineAbsoluteHypotheticalFragment(_) => {
// FIXME(pcwalton): This is a bit of an abuse of the logging infrastructure. We
// should have a real `SERVO_DEBUG` system.
debug!("{:?}",
self.build_debug_borders_around_fragment(display_list,
flow_origin,
clip_rect))
}
ImageFragment(ref mut image_fragment) => {
let image_ref = &mut image_fragment.image;
match image_ref.get_image(self.node.to_untrusted_node_address()) {
Some(image) => {
debug!("(building display list) building image fragment");
// Place the image into the display list.
let image_display_item = box ImageDisplayItem {
base: BaseDisplayItem::new(absolute_content_box,
self.node,
ContentStackingLevel,
*clip_rect),
image: image.clone(),
stretch_size: absolute_content_box.size,
};
display_list.push(ImageDisplayItemClass(image_display_item))
}
None => {
// No image data at all? Do nothing.
//
// TODO: Add some kind of placeholder image.
debug!("(building display list) no image :(");
}
}
}
}
// FIXME(pcwalton): This is a bit of an abuse of the logging
// infrastructure. We should have a real `SERVO_DEBUG` system.
debug!("{:?}",
self.build_debug_borders_around_fragment(display_list, flow_origin, clip_rect))
// If this is an iframe, then send its position and size up to the constellation.
//
// FIXME(pcwalton): Doing this during display list construction seems potentially
// problematic if iframes are outside the area we're computing the display list for, since
// they won't be able to reflow at all until the user scrolls to them. Perhaps we should
// separate this into two parts: first we should send the size only to the constellation
// once that's computed during assign-block-sizes, and second we should should send the
// origin to the constellation here during display list construction. This should work
// because layout for the iframe only needs to know size, and origin is only relevant if
// the iframe is actually going to be displayed.
match self.specific {
IframeFragment(ref iframe_fragment) => {
self.finalize_position_and_size_of_iframe(iframe_fragment,
absolute_fragment_bounds.origin,
layout_context)
}
_ => {}
}
}
/// Computes the intrinsic inline-sizes of this fragment.
pub fn compute_intrinsic_inline_sizes(&mut self) -> IntrinsicISizesContribution {
let mut result = self.style_specified_intrinsic_inline_size();
match self.specific {
GenericFragment | IframeFragment(_) | TableFragment | TableCellFragment |
TableColumnFragment(_) | TableRowFragment | TableWrapperFragment |
InlineAbsoluteHypotheticalFragment(_) | InputFragment => {}
InlineBlockFragment(ref mut info) => {
let block_flow = info.flow_ref.as_block();
result.union_block(&block_flow.base.intrinsic_inline_sizes)
}
ImageFragment(ref mut image_fragment_info) => {
let image_inline_size = image_fragment_info.image_inline_size();
result.union_block(&IntrinsicISizes {
minimum_inline_size: image_inline_size,
preferred_inline_size: image_inline_size,
})
}
ScannedTextFragment(ref text_fragment_info) => {
let range = &text_fragment_info.range;
let min_line_inline_size = text_fragment_info.run.min_width_for_range(range);
// See http://dev.w3.org/csswg/css-sizing/#max-content-inline-size.
// TODO: Account for soft wrap opportunities.
let max_line_inline_size = text_fragment_info.run
.metrics_for_range(range)
.advance_width;
result.union_block(&IntrinsicISizes {
minimum_inline_size: min_line_inline_size,
preferred_inline_size: max_line_inline_size,
})
}
UnscannedTextFragment(..) => {
fail!("Unscanned text fragments should have been scanned by now!")
}
};
// Take borders and padding for parent inline fragments into account, if necessary.
if self.is_primary_fragment() {
match self.inline_context {
None => {}
Some(ref context) => {
for style in context.styles.iter() {
let border_width = style.logical_border_width().inline_start_end();
let padding_inline_size =
model::padding_from_style(&**style, Au(0)).inline_start_end();
result.surrounding_size = result.surrounding_size + border_width +
padding_inline_size;
}
}
}
}
result
}
/// TODO: What exactly does this function return? Why is it Au(0) for GenericFragment?
pub fn content_inline_size(&self) -> Au {
match self.specific {
GenericFragment | IframeFragment(_) | TableFragment | TableCellFragment |
TableRowFragment | TableWrapperFragment | InlineBlockFragment(_) |
InputFragment | InlineAbsoluteHypotheticalFragment(_) => Au(0),
ImageFragment(ref image_fragment_info) => {
image_fragment_info.computed_inline_size()
}
ScannedTextFragment(ref text_fragment_info) => {
let (range, run) = (&text_fragment_info.range, &text_fragment_info.run);
let text_bounds = run.metrics_for_range(range).bounding_box;
text_bounds.size.width
}
TableColumnFragment(_) => fail!("Table column fragments do not have inline_size"),
UnscannedTextFragment(_) => fail!("Unscanned text fragments should have been scanned by now!"),
}
}
/// Returns, and computes, the block-size of this fragment.
pub fn content_block_size(&self, layout_context: &LayoutContext) -> Au {
match self.specific {
GenericFragment | IframeFragment(_) | TableFragment | TableCellFragment |
TableRowFragment | TableWrapperFragment | InlineBlockFragment(_) |
InputFragment | InlineAbsoluteHypotheticalFragment(_) => Au(0),
ImageFragment(ref image_fragment_info) => {
image_fragment_info.computed_block_size()
}
ScannedTextFragment(_) => {
// Compute the block-size based on the line-block-size and font size.
self.calculate_line_height(layout_context)
}
TableColumnFragment(_) => fail!("Table column fragments do not have block_size"),
UnscannedTextFragment(_) => fail!("Unscanned text fragments should have been scanned by now!"),
}
}
/// Returns the dimensions of the content box.
///
/// This is marked `#[inline]` because it is frequently called when only one or two of the
/// values are needed and that will save computation.
#[inline]
pub fn content_box(&self) -> LogicalRect<Au> {
self.border_box - self.border_padding
}
/// Find the split of a fragment that includes a new-line character.
///
/// A return value of `None` indicates that the fragment is not splittable.
/// Otherwise the split information is returned. The right information is
/// optional due to the possibility of it being whitespace.
//
// TODO(bjz): The text run should be removed in the future, but it is currently needed for
// the current method of fragment splitting in the `inline::try_append_*` functions.
pub fn find_split_info_by_new_line(&self)
-> Option<(SplitInfo, Option<SplitInfo>, Arc<Box<TextRun>> /* TODO(bjz): remove */)> {
match self.specific {
GenericFragment | IframeFragment(_) | ImageFragment(_) | TableFragment | TableCellFragment |
TableRowFragment | TableWrapperFragment | InputFragment => None,
TableColumnFragment(_) => fail!("Table column fragments do not need to split"),
UnscannedTextFragment(_) => fail!("Unscanned text fragments should have been scanned by now!"),
InlineBlockFragment(_) | InlineAbsoluteHypotheticalFragment(_) => {
fail!("Inline blocks or inline absolute hypothetical fragments do not get split")
}
ScannedTextFragment(ref text_fragment_info) => {
let mut new_line_pos = self.new_line_pos.clone();
let cur_new_line_pos = new_line_pos.remove(0).unwrap();
let inline_start_range = Range::new(text_fragment_info.range.begin(), cur_new_line_pos);
let inline_end_range = Range::new(text_fragment_info.range.begin() + cur_new_line_pos + CharIndex(1),
text_fragment_info.range.length() - (cur_new_line_pos + CharIndex(1)));
// Left fragment is for inline-start text of first founded new-line character.
let inline_start_fragment = SplitInfo::new(inline_start_range, text_fragment_info);
// Right fragment is for inline-end text of first founded new-line character.
let inline_end_fragment = if inline_end_range.length() > CharIndex(0) {
Some(SplitInfo::new(inline_end_range, text_fragment_info))
} else {
None
};
Some((inline_start_fragment, inline_end_fragment, text_fragment_info.run.clone()))
}
}
}
/// Attempts to find the split positions of a text fragment so that its inline-size is
/// no more than `max_inline-size`.
///
/// A return value of `None` indicates that the fragment could not be split.
/// Otherwise the information pertaining to the split is returned. The inline-start
/// and inline-end split information are both optional due to the possibility of
/// them being whitespace.
//
// TODO(bjz): The text run should be removed in the future, but it is currently needed for
// the current method of fragment splitting in the `inline::try_append_*` functions.
pub fn find_split_info_for_inline_size(&self, start: CharIndex, max_inline_size: Au, starts_line: bool)
-> Option<(Option<SplitInfo>, Option<SplitInfo>, Arc<Box<TextRun>> /* TODO(bjz): remove */)> {
match self.specific {
GenericFragment | IframeFragment(_) | ImageFragment(_) | TableFragment | TableCellFragment |
TableRowFragment | TableWrapperFragment | InlineBlockFragment(_) | InputFragment |
InlineAbsoluteHypotheticalFragment(_) => None,
TableColumnFragment(_) => fail!("Table column fragments do not have inline_size"),
UnscannedTextFragment(_) => fail!("Unscanned text fragments should have been scanned by now!"),
ScannedTextFragment(ref text_fragment_info) => {
let mut pieces_processed_count: uint = 0;
let mut remaining_inline_size: Au = max_inline_size;
let mut inline_start_range = Range::new(text_fragment_info.range.begin() + start, CharIndex(0));
let mut inline_end_range: Option<Range<CharIndex>> = None;
debug!("split_to_inline_size: splitting text fragment (strlen={}, range={}, avail_inline_size={})",
text_fragment_info.run.text.len(),
text_fragment_info.range,
max_inline_size);
for (glyphs, offset, slice_range) in text_fragment_info.run.iter_slices_for_range(
&text_fragment_info.range) {
debug!("split_to_inline_size: considering slice (offset={}, range={}, \
remain_inline_size={})",
offset,
slice_range,
remaining_inline_size);
let metrics = text_fragment_info.run.metrics_for_slice(glyphs, &slice_range);
let advance = metrics.advance_width;
let should_continue;
if advance <= remaining_inline_size || glyphs.is_whitespace() {
should_continue = true;
if starts_line && pieces_processed_count == 0 && glyphs.is_whitespace() {
debug!("split_to_inline_size: case=skipping leading trimmable whitespace");
inline_start_range.shift_by(slice_range.length());
} else {
debug!("split_to_inline_size: case=enlarging span");
remaining_inline_size = remaining_inline_size - advance;
inline_start_range.extend_by(slice_range.length());
}
} else {
// The advance is more than the remaining inline-size.
should_continue = false;
let slice_begin = offset + slice_range.begin();
if slice_begin < text_fragment_info.range.end() {
// There are still some things inline-start over at the end of the line. Create
// the inline-end chunk.
let inline_end_range_end = text_fragment_info.range.end() - slice_begin;
inline_end_range = Some(Range::new(slice_begin, inline_end_range_end));
debug!("split_to_inline_size: case=splitting remainder with inline_end range={:?}",
inline_end_range);
}
}
pieces_processed_count += 1;
if !should_continue {
break
}
}
let inline_start_is_some = inline_start_range.length() > CharIndex(0);
if (pieces_processed_count == 1 || !inline_start_is_some) && !starts_line {
None
} else {
let inline_start = if inline_start_is_some {
Some(SplitInfo::new(inline_start_range, text_fragment_info))
} else {
None
};
let inline_end = inline_end_range.map(|inline_end_range| {
SplitInfo::new(inline_end_range, text_fragment_info)
});
Some((inline_start, inline_end, text_fragment_info.run.clone()))
}
}
}
}
/// Returns true if this fragment is an unscanned text fragment that consists entirely of
/// whitespace that should be stripped.
pub fn is_ignorable_whitespace(&self) -> bool {
match self.white_space() {
white_space::pre => return false,
white_space::normal | white_space::nowrap => {}
}
match self.specific {
UnscannedTextFragment(ref text_fragment_info) => {
is_whitespace(text_fragment_info.text.as_slice())
}
_ => false,
}
}
/// Assigns replaced inline-size, padding, and margins for this fragment only if it is replaced
/// content per CSS 2.1 § 10.3.2.
pub fn assign_replaced_inline_size_if_necessary(&mut self, container_inline_size: Au) {
match self.specific {
GenericFragment | IframeFragment(_) | TableFragment | TableCellFragment |
TableRowFragment | TableWrapperFragment | InputFragment => return,
TableColumnFragment(_) => fail!("Table column fragments do not have inline_size"),
UnscannedTextFragment(_) => {
fail!("Unscanned text fragments should have been scanned by now!")
}
ImageFragment(_) | ScannedTextFragment(_) | InlineBlockFragment(_) |
InlineAbsoluteHypotheticalFragment(_) => {}
};
let style_inline_size = self.style().content_inline_size();
let style_block_size = self.style().content_block_size();
let style_min_inline_size = self.style().min_inline_size();
let style_max_inline_size = self.style().max_inline_size();
let style_min_block_size = self.style().min_block_size();
let style_max_block_size = self.style().max_block_size();
let noncontent_inline_size = self.border_padding.inline_start_end();
match self.specific {
InlineAbsoluteHypotheticalFragment(ref mut info) => {
let block_flow = info.flow_ref.as_block();
block_flow.base.position.size.inline =
block_flow.base.intrinsic_inline_sizes.preferred_inline_size;
// This is a hypothetical box, so it takes up no space.
self.border_box.size.inline = Au(0);
}
InlineBlockFragment(ref mut info) => {
let block_flow = info.flow_ref.as_block();
self.border_box.size.inline =
block_flow.base.intrinsic_inline_sizes.preferred_inline_size;
block_flow.base.block_container_inline_size = self.border_box.size.inline;
}
ScannedTextFragment(ref info) => {
// Scanned text fragments will have already had their content inline-sizes assigned
// by this point.
self.border_box.size.inline = info.content_inline_size + noncontent_inline_size
}
ImageFragment(ref mut image_fragment_info) => {
// TODO(ksh8281): compute border,margin
let inline_size = ImageFragmentInfo::style_length(
style_inline_size,
image_fragment_info.dom_inline_size,
container_inline_size);
let inline_size = match inline_size {
Auto => {
let intrinsic_width = image_fragment_info.image_inline_size();
let intrinsic_height = image_fragment_info.image_block_size();
if intrinsic_height == Au(0) {
intrinsic_width
} else {
let ratio = intrinsic_width.to_f32().unwrap() /
intrinsic_height.to_f32().unwrap();
let specified_height = ImageFragmentInfo::style_length(
style_block_size,
image_fragment_info.dom_block_size,
Au(0));
let specified_height = match specified_height {
Auto => intrinsic_height,
Specified(h) => h,
};
let specified_height = ImageFragmentInfo::clamp_size(
specified_height,
style_min_block_size,
style_max_block_size,
Au(0));
Au((specified_height.to_f32().unwrap() * ratio) as i32)
}
},
Specified(w) => w,
};
let inline_size = ImageFragmentInfo::clamp_size(inline_size,
style_min_inline_size,
style_max_inline_size,
container_inline_size);
self.border_box.size.inline = inline_size + noncontent_inline_size;
image_fragment_info.computed_inline_size = Some(inline_size);
}
_ => fail!("this case should have been handled above"),
}
}
/// Assign block-size for this fragment if it is replaced content. The inline-size must have
/// been assigned first.
///
/// Ideally, this should follow CSS 2.1 § 10.6.2.
pub fn assign_replaced_block_size_if_necessary(&mut self, containing_block_block_size: Au) {
match self.specific {
GenericFragment | IframeFragment(_) | TableFragment | TableCellFragment |
TableRowFragment | TableWrapperFragment | InputFragment => return,
TableColumnFragment(_) => fail!("Table column fragments do not have block_size"),
UnscannedTextFragment(_) => {
fail!("Unscanned text fragments should have been scanned by now!")
}
ImageFragment(_) | ScannedTextFragment(_) | InlineBlockFragment(_) |
InlineAbsoluteHypotheticalFragment(_) => {}
}
let style_block_size = self.style().content_block_size();
let style_min_block_size = self.style().min_block_size();
let style_max_block_size = self.style().max_block_size();
let noncontent_block_size = self.border_padding.block_start_end();
match self.specific {
ImageFragment(ref mut image_fragment_info) => {
// TODO(ksh8281): compute border,margin,padding
let inline_size = image_fragment_info.computed_inline_size();
let block_size = ImageFragmentInfo::style_length(
style_block_size,
image_fragment_info.dom_block_size,
containing_block_block_size);
let block_size = match block_size {
Auto => {
let scale = image_fragment_info.image_inline_size().to_f32().unwrap()
/ inline_size.to_f32().unwrap();
Au((image_fragment_info.image_block_size().to_f32().unwrap() / scale)
as i32)
},
Specified(h) => {
h
}
};
let block_size = ImageFragmentInfo::clamp_size(block_size, style_min_block_size,
style_max_block_size,
Au(0));
image_fragment_info.computed_block_size = Some(block_size);
self.border_box.size.block = block_size + noncontent_block_size
}
ScannedTextFragment(_) => {
// Scanned text fragments' content block-sizes are calculated by the text run
// scanner during flow construction.
self.border_box.size.block = self.border_box.size.block + noncontent_block_size
}
InlineBlockFragment(ref mut info) => {
// Not the primary fragment, so we do not take the noncontent size into account.
let block_flow = info.flow_ref.as_block();
self.border_box.size.block = block_flow.base.position.size.block +
block_flow.fragment.margin.block_start_end()
}
InlineAbsoluteHypotheticalFragment(ref mut info) => {
// Not the primary fragment, so we do not take the noncontent size into account.
let block_flow = info.flow_ref.as_block();
self.border_box.size.block = block_flow.base.position.size.block;
}
_ => fail!("should have been handled above"),
}
}
/// Calculates block-size above baseline, depth below baseline, and ascent for this fragment when
/// used in an inline formatting context. See CSS 2.1 § 10.8.1.
pub fn inline_metrics(&self, layout_context: &LayoutContext) -> InlineMetrics {
match self.specific {
ImageFragment(ref image_fragment_info) => {
let computed_block_size = image_fragment_info.computed_block_size();
InlineMetrics {
block_size_above_baseline: computed_block_size + self.border_padding.block_start_end(),
depth_below_baseline: Au(0),
ascent: computed_block_size + self.border_padding.block_end,
}
}
ScannedTextFragment(ref text_fragment) => {
// See CSS 2.1 § 10.8.1.
let line_height = self.calculate_line_height(layout_context);
InlineMetrics::from_font_metrics(&text_fragment.run.font_metrics, line_height)
}
InlineBlockFragment(ref info) => {
// See CSS 2.1 § 10.8.1.
let block_flow = info.flow_ref.deref().as_immutable_block();
let font_style = self.style.get_font();
let font_metrics = text::font_metrics_for_style(layout_context.font_context(),
font_style);
InlineMetrics::from_block_height(&font_metrics,
block_flow.base.position.size.block +
block_flow.fragment.margin.block_start_end())
}
InlineAbsoluteHypotheticalFragment(_) => {
// Hypothetical boxes take up no space.
InlineMetrics {
block_size_above_baseline: Au(0),
depth_below_baseline: Au(0),
ascent: Au(0),
}
}
_ => {
InlineMetrics {
block_size_above_baseline: self.border_box.size.block,
depth_below_baseline: Au(0),
ascent: self.border_box.size.block,
}
}
}
}
/// Returns true if this fragment is a hypothetical box. See CSS 2.1 § 10.3.7.
pub fn is_hypothetical(&self) -> bool {
match self.specific {
InlineAbsoluteHypotheticalFragment(_) => true,
_ => false,
}
}
/// Returns true if this fragment can merge with another adjacent fragment or false otherwise.
pub fn can_merge_with_fragment(&self, other: &Fragment) -> bool {
match (&self.specific, &other.specific) {
(&UnscannedTextFragment(_), &UnscannedTextFragment(_)) => {
// FIXME: Should probably use a whitelist of styles that can safely differ (#3165)
self.style().get_font() == other.style().get_font() &&
self.text_decoration() == other.text_decoration() &&
self.white_space() == other.white_space()
}
_ => false,
}
}
/// Sends the size and position of this iframe fragment to the constellation. This is out of
/// line to guide inlining.
#[inline(never)]
fn finalize_position_and_size_of_iframe(&self,
iframe_fragment: &IframeFragmentInfo,
offset: Point2D<Au>,
layout_context: &LayoutContext) {
let border_padding = (self.border_padding).to_physical(self.style.writing_mode);
let content_size = self.content_box().size.to_physical(self.style.writing_mode);
let iframe_rect = Rect(Point2D(geometry::to_frac_px(offset.x + border_padding.left) as f32,
geometry::to_frac_px(offset.y + border_padding.top) as f32),
Size2D(geometry::to_frac_px(content_size.width) as f32,
geometry::to_frac_px(content_size.height) as f32));
debug!("finalizing position and size of iframe for {:?},{:?}",
iframe_fragment.pipeline_id,
iframe_fragment.subpage_id);
let ConstellationChan(ref chan) = layout_context.shared.constellation_chan;
chan.send(FrameRectMsg(iframe_fragment.pipeline_id,
iframe_fragment.subpage_id,
iframe_rect));
}
/// Returns true if and only if this is the *primary fragment* for the fragment's style object
/// (conceptually, though style sharing makes this not really true, of course). The primary
/// fragment is the one that draws backgrounds, borders, etc., and takes borders, padding and
/// margins into account. Every style object has at most one primary fragment.
///
/// At present, all fragments are primary fragments except for inline-block and table wrapper
/// fragments. Inline-block fragments are not primary fragments because the corresponding block
/// flow is the primary fragment, while table wrapper fragments are not primary fragments
/// because the corresponding table flow is the primary fragment.
fn is_primary_fragment(&self) -> bool {
match self.specific {
InlineBlockFragment(_) | InlineAbsoluteHypotheticalFragment(_) |
TableWrapperFragment => false,
GenericFragment | IframeFragment(_) | ImageFragment(_) | ScannedTextFragment(_) |
TableFragment | TableCellFragment | TableColumnFragment(_) | TableRowFragment |
UnscannedTextFragment(_) | InputFragment => true,
}
}
pub fn update_late_computed_inline_position_if_necessary(&mut self) {
match self.specific {
InlineAbsoluteHypotheticalFragment(ref mut info) => {
let position = self.border_box.start.i;
info.flow_ref.update_late_computed_inline_position_if_necessary(position)
}
_ => {}
}
}
pub fn update_late_computed_block_position_if_necessary(&mut self) {
match self.specific {
InlineAbsoluteHypotheticalFragment(ref mut info) => {
let position = self.border_box.start.b;
info.flow_ref.update_late_computed_block_position_if_necessary(position)
}
_ => {}
}
}
pub fn clip_rect_for_children(&self, current_clip_rect: Rect<Au>, flow_origin: Point2D<Au>)
-> Rect<Au> {
// Don't clip if we're text.
match self.specific {
ScannedTextFragment(_) => return current_clip_rect,
_ => {}
}
// Only clip if `overflow` tells us to.
match self.style.get_box().overflow {
overflow::hidden | overflow::auto | overflow::scroll => {}
_ => return current_clip_rect,
}
// Create a new clip rect.
//
// FIXME(#2795): Get the real container size.
let physical_rect = self.border_box.to_physical(self.style.writing_mode, Size2D::zero());
current_clip_rect.intersection(&Rect(physical_rect.origin + flow_origin,
physical_rect.size)).unwrap_or(ZERO_RECT)
}
}
impl fmt::Show for Fragment {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
try!(write!(f, "({} {} ", self.debug_id(), self.specific.get_type()));
try!(write!(f, "bp {}", self.border_padding));
try!(write!(f, " "));
try!(write!(f, "m {}", self.margin));
write!(f, ")")
}
}
bitflags! {
flags QuantitiesIncludedInIntrinsicInlineSizes: u8 {
static IntrinsicInlineSizeIncludesMargins = 0x01,
static IntrinsicInlineSizeIncludesPadding = 0x02,
static IntrinsicInlineSizeIncludesBorder = 0x04,
static IntrinsicInlineSizeIncludesSpecified = 0x08,
}
}
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