Auto merge of #14490 - stshine:replaced-size, r=emilio

layout: Unify size calculation of replaced elements

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- [ ] These changes fix #__ (github issue number if applicable).

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components/layout/block.rs

@@ -42,12 +42,11 @@ use flow::IS_ABSOLUTELY_POSITIONED;
 use flow_list::FlowList;
 use fragment::{CoordinateSystem, Fragment, FragmentBorderBoxIterator, Overflow};
 use fragment::{IS_INLINE_FLEX_ITEM, IS_BLOCK_FLEX_ITEM};
-use fragment::SpecificFragmentInfo;
 use gfx::display_list::{ClippingRegion, StackingContext};
 use gfx_traits::ScrollRootId;
 use gfx_traits::print_tree::PrintTree;
 use layout_debug;
-use model::{CollapsibleMargins, IntrinsicISizes, MarginCollapseInfo, MaybeAuto};
+use model::{AdjoiningMargins, CollapsibleMargins, IntrinsicISizes, MarginCollapseInfo, MaybeAuto};
 use model::{specified, specified_or_none};
 use sequential;
 use serde::{Serialize, Serializer};
@@ -555,7 +554,7 @@ impl BlockFlow {
     /// relevant margins for this Block.
     pub fn block_type(&self) -> BlockType {
         if self.base.flags.contains(IS_ABSOLUTELY_POSITIONED) {
-            if self.is_replaced_content() {
+            if self.fragment.is_replaced() {
                 BlockType::AbsoluteReplaced
             } else {
                 BlockType::AbsoluteNonReplaced
@@ -563,19 +562,19 @@ impl BlockFlow {
         } else if self.is_inline_flex_item() {
             BlockType::InlineFlexItem
         } else if self.base.flags.is_float() {
-            if self.is_replaced_content() {
+            if self.fragment.is_replaced() {
                 BlockType::FloatReplaced
             } else {
                 BlockType::FloatNonReplaced
             }
         } else if self.is_inline_block() {
-            if self.is_replaced_content() {
+            if self.fragment.is_replaced() {
                 BlockType::InlineBlockReplaced
             } else {
                 BlockType::InlineBlockNonReplaced
             }
         } else {
-            if self.is_replaced_content() {
+            if self.fragment.is_replaced() {
                 BlockType::Replaced
             } else {
                 BlockType::NonReplaced
@@ -668,22 +667,6 @@ impl BlockFlow {
         }
     }
 
-    /// Return true if this has a replaced fragment.
-    ///
-    /// Text, Images, Inline Block and Canvas
-    /// (https://html.spec.whatwg.org/multipage/#replaced-elements) fragments are considered as
-    /// replaced fragments.
-    fn is_replaced_content(&self) -> bool {
-        match self.fragment.specific {
-            SpecificFragmentInfo::ScannedText(_) |
-            SpecificFragmentInfo::Svg(_) |
-            SpecificFragmentInfo::Image(_) |
-            SpecificFragmentInfo::Canvas(_) |
-            SpecificFragmentInfo::InlineBlock(_) => true,
-            _ => false,
-        }
-    }
-
     /// Return shrink-to-fit inline-size.
     ///
     /// This is where we use the preferred inline-sizes and minimum inline-sizes
@@ -1267,11 +1250,11 @@ impl BlockFlow {
 
             let available_block_size = containing_block_block_size -
                 self.fragment.border_padding.block_start_end();
-            if self.is_replaced_content() {
+            if self.fragment.is_replaced() {
                 // Calculate used value of block-size just like we do for inline replaced elements.
                 // TODO: Pass in the containing block block-size when Fragment's
                 // assign-block-size can handle it correctly.
-                self.fragment.assign_replaced_block_size_if_necessary(Some(containing_block_block_size));
+                self.fragment.assign_replaced_block_size_if_necessary();
                 // TODO: Right now, this content block-size value includes the
                 // margin because of erroneous block-size calculation in fragment.
                 // Check this when that has been fixed.
@@ -1896,16 +1879,22 @@ impl Flow for BlockFlow {
     fn fragment(&mut self, layout_context: &LayoutContext,
                 fragmentation_context: Option<FragmentationContext>)
                 -> Option<Arc<Flow>> {
-        if self.is_replaced_content() {
+        if self.fragment.is_replaced() {
             let _scope = layout_debug_scope!("assign_replaced_block_size_if_necessary {:x}",
                                              self.base.debug_id());
 
             // Assign block-size for fragment if it is an image fragment.
-            let containing_block_block_size =
+            self.fragment.assign_replaced_block_size_if_necessary();
-                self.base.block_container_explicit_block_size;
-            self.fragment.assign_replaced_block_size_if_necessary(containing_block_block_size);
             if !self.base.flags.contains(IS_ABSOLUTELY_POSITIONED) {
                 self.base.position.size.block = self.fragment.border_box.size.block;
+                let mut block_start = AdjoiningMargins::from_margin(self.fragment.margin.block_start);
+                let block_end = AdjoiningMargins::from_margin(self.fragment.margin.block_end);
+                if self.fragment.border_box.size.block == Au(0) {
+                    block_start.union(block_end);
+                    self.base.collapsible_margins = CollapsibleMargins::CollapseThrough(block_start);
+                } else {
+                    self.base.collapsible_margins = CollapsibleMargins::Collapse(block_start, block_end);
+                }
                 self.base.restyle_damage.remove(REFLOW_OUT_OF_FLOW | REFLOW);
                 self.fragment.restyle_damage.remove(REFLOW_OUT_OF_FLOW | REFLOW);
             }
@@ -2870,7 +2859,7 @@ impl ISizeAndMarginsComputer for AbsoluteReplaced {
         fragment.assign_replaced_inline_size_if_necessary(containing_block_inline_size, container_block_size);
         // For replaced absolute flow, the rest of the constraint solving will
         // take inline-size to be specified as the value computed here.
-        MaybeAuto::Specified(fragment.content_inline_size())
+        MaybeAuto::Specified(fragment.content_box().size.inline)
     }
 
     fn containing_block_inline_size(&self,
@@ -2929,7 +2918,7 @@ impl ISizeAndMarginsComputer for BlockReplaced {
         fragment.assign_replaced_inline_size_if_necessary(parent_flow_inline_size, container_block_size);
         // For replaced block flow, the rest of the constraint solving will
         // take inline-size to be specified as the value computed here.
-        MaybeAuto::Specified(fragment.content_inline_size())
+        MaybeAuto::Specified(fragment.content_box().size.inline)
     }
 
 }
@@ -2987,7 +2976,7 @@ impl ISizeAndMarginsComputer for FloatReplaced {
         fragment.assign_replaced_inline_size_if_necessary(parent_flow_inline_size, container_block_size);
         // For replaced block flow, the rest of the constraint solving will
         // take inline-size to be specified as the value computed here.
-        MaybeAuto::Specified(fragment.content_inline_size())
+        MaybeAuto::Specified(fragment.content_box().size.inline)
     }
 }
 
@@ -3075,7 +3064,7 @@ impl ISizeAndMarginsComputer for InlineBlockReplaced {
         fragment.assign_replaced_inline_size_if_necessary(parent_flow_inline_size, container_block_size);
         // For replaced block flow, the rest of the constraint solving will
         // take inline-size to be specified as the value computed here.
-        MaybeAuto::Specified(fragment.content_inline_size())
+        MaybeAuto::Specified(fragment.content_box().size.inline)
     }
 }
 

components/layout/construct.rs

@@ -346,14 +346,12 @@ impl<'a, ConcreteThreadSafeLayoutNode: ThreadSafeLayoutNode>
                 SpecificFragmentInfo::Iframe(IframeFragmentInfo::new(node))
             }
             Some(LayoutNodeType::Element(LayoutElementType::HTMLImageElement)) => {
-                let image_info = box ImageFragmentInfo::new(node,
+                let image_info = box ImageFragmentInfo::new(node.image_url(),
-                                                            node.image_url(),
                                                             &self.layout_context.shared);
                 SpecificFragmentInfo::Image(image_info)
             }
             Some(LayoutNodeType::Element(LayoutElementType::HTMLObjectElement)) => {
-                let image_info = box ImageFragmentInfo::new(node,
+                let image_info = box ImageFragmentInfo::new(node.object_data(),
-                                                            node.object_data(),
                                                             &self.layout_context.shared);
                 SpecificFragmentInfo::Image(image_info)
             }
@@ -372,11 +370,11 @@ impl<'a, ConcreteThreadSafeLayoutNode: ThreadSafeLayoutNode>
             }
             Some(LayoutNodeType::Element(LayoutElementType::HTMLCanvasElement)) => {
                 let data = node.canvas_data().unwrap();
-                SpecificFragmentInfo::Canvas(box CanvasFragmentInfo::new(node, data, self.style_context()))
+                SpecificFragmentInfo::Canvas(box CanvasFragmentInfo::new(data))
             }
             Some(LayoutNodeType::Element(LayoutElementType::SVGSVGElement)) => {
                 let data = node.svg_data().unwrap();
-                SpecificFragmentInfo::Svg(box SvgFragmentInfo::new(node, data, self.style_context()))
+                SpecificFragmentInfo::Svg(box SvgFragmentInfo::new(data))
             }
             _ => {
                 // This includes pseudo-elements.
@@ -1207,8 +1205,7 @@ impl<'a, ConcreteThreadSafeLayoutNode: ThreadSafeLayoutNode>
         let flotation = FloatKind::from_property(flotation);
         let marker_fragments = match node.style(self.style_context()).get_list().list_style_image {
             Either::First(ref url_value) => {
-                let image_info = box ImageFragmentInfo::new(node,
+                let image_info = box ImageFragmentInfo::new(url_value.url().map(|u| u.clone()),
-                                                            url_value.url().map(|u| u.clone()),
                                                             &self.layout_context.shared);
                 vec![Fragment::new(node, SpecificFragmentInfo::Image(image_info), self.layout_context)]
             }

components/layout/display_list_builder.rs

@@ -1489,13 +1489,8 @@ impl FragmentDisplayListBuilding for Fragment {
                 }
             }
             SpecificFragmentInfo::Canvas(ref canvas_fragment_info) => {
-                let width = canvas_fragment_info.replaced_image_fragment_info
+                let computed_width = canvas_fragment_info.dom_width.to_px();
-                    .computed_inline_size.map_or(0, |w| w.to_px() as usize);
+                let computed_height = canvas_fragment_info.dom_height.to_px();
-                let height = canvas_fragment_info.replaced_image_fragment_info
-                    .computed_block_size.map_or(0, |h| h.to_px() as usize);
-                if width > 0 && height > 0 {
-                    let computed_width = canvas_fragment_info.canvas_inline_size().to_px();
-                    let computed_height = canvas_fragment_info.canvas_block_size().to_px();
 
                 let canvas_data = match canvas_fragment_info.ipc_renderer {
                     Some(ref ipc_renderer) => {
@@ -1540,7 +1535,6 @@ impl FragmentDisplayListBuilding for Fragment {
 
                 state.add_display_item(display_item);
             }
-            }
             SpecificFragmentInfo::UnscannedText(_) => {
                 panic!("Shouldn't see unscanned fragments here.")
             }

components/layout/flex.rs

@@ -19,7 +19,7 @@ use fragment::{Fragment, FragmentBorderBoxIterator, Overflow};
 use gfx::display_list::StackingContext;
 use gfx_traits::ScrollRootId;
 use layout_debug;
-use model::{IntrinsicISizes, MaybeAuto, MinMaxConstraint};
+use model::{IntrinsicISizes, MaybeAuto, SizeConstraint};
 use model::{specified, specified_or_none};
 use std::cmp::{max, min};
 use std::ops::Range;
@@ -38,7 +38,7 @@ use style::values::computed::{LengthOrPercentageOrAutoOrContent, LengthOrPercent
 #[derive(Debug)]
 enum AxisSize {
     Definite(Au),
-    MinMax(MinMaxConstraint),
+    MinMax(SizeConstraint),
     Infinite,
 }
 
@@ -62,7 +62,7 @@ impl AxisSize {
                 }
             }
             LengthOrPercentageOrAuto::Auto => {
-                AxisSize::MinMax(MinMaxConstraint::new(content_size, min, max))
+                AxisSize::MinMax(SizeConstraint::new(content_size, min, max, None))
             }
         }
     }

components/layout/fragment.rs

@@ -23,7 +23,8 @@ use inline::{InlineMetrics, LAST_FRAGMENT_OF_ELEMENT, LineMetrics};
 use ipc_channel::ipc::IpcSender;
 #[cfg(debug_assertions)]
 use layout_debug;
-use model::{self, IntrinsicISizes, IntrinsicISizesContribution, MaybeAuto};
+use model::{self, IntrinsicISizes, IntrinsicISizesContribution, MaybeAuto, SizeConstraint};
+use model::style_length;
 use msg::constellation_msg::PipelineId;
 use net_traits::image::base::{Image, ImageMetadata};
 use net_traits::image_cache_thread::{ImageOrMetadataAvailable, UsePlaceholder};
@@ -34,7 +35,7 @@ use script_layout_interface::wrapper_traits::{PseudoElementType, ThreadSafeLayou
 use serde::{Serialize, Serializer};
 use servo_url::ServoUrl;
 use std::borrow::ToOwned;
-use std::cmp::{max, min};
+use std::cmp::{Ordering, max, min};
 use std::collections::LinkedList;
 use std::fmt;
 use std::sync::{Arc, Mutex};
@@ -43,7 +44,6 @@ use style::computed_values::{border_collapse, box_sizing, clear, color, display,
 use style::computed_values::{overflow_wrap, overflow_x, position, text_decoration};
 use style::computed_values::{transform_style, vertical_align, white_space, word_break, z_index};
 use style::computed_values::content::ContentItem;
-use style::context::SharedStyleContext;
 use style::logical_geometry::{Direction, LogicalMargin, LogicalRect, LogicalSize, WritingMode};
 use style::properties::ServoComputedValues;
 use style::selector_parser::RestyleDamage;
@@ -51,7 +51,6 @@ use style::servo::restyle_damage::RECONSTRUCT_FLOW;
 use style::str::char_is_whitespace;
 use style::values::Either;
 use style::values::computed::{LengthOrPercentage, LengthOrPercentageOrAuto};
-use style::values::computed::LengthOrPercentageOrNone;
 use text;
 use text::TextRunScanner;
 
@@ -59,6 +58,10 @@ use text::TextRunScanner;
 static FONT_SUBSCRIPT_OFFSET_RATIO: f32 = 0.20;
 static FONT_SUPERSCRIPT_OFFSET_RATIO: f32 = 0.34;
 
+// https://drafts.csswg.org/css-images/#default-object-size
+static DEFAULT_REPLACED_WIDTH: i32 = 300;
+static DEFAULT_REPLACED_HEIGHT: i32 = 150;
+
 /// 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:
@@ -247,21 +250,6 @@ impl fmt::Debug for SpecificFragmentInfo {
     }
 }
 
-/// Clamp a value obtained from style_length, based on min / max lengths.
-fn clamp_size(size: Au,
-              min_size: LengthOrPercentage,
-              max_size: LengthOrPercentageOrNone,
-              container_size: Au)
-              -> Au {
-    let min_size = model::specified(min_size, container_size);
-    let max_size = model::specified_or_none(max_size, container_size);
-
-    max(min_size, match max_size {
-        None => size,
-        Some(max_size) => min(size, max_size),
-    })
-}
-
 /// Information for generated content.
 #[derive(Clone)]
 pub enum GeneratedContentInfo {
@@ -326,89 +314,41 @@ impl InlineAbsoluteFragmentInfo {
 
 #[derive(Clone)]
 pub struct CanvasFragmentInfo {
-    pub replaced_image_fragment_info: ReplacedImageFragmentInfo,
     pub ipc_renderer: Option<Arc<Mutex<IpcSender<CanvasMsg>>>>,
     pub dom_width: Au,
     pub dom_height: Au,
 }
 
 impl CanvasFragmentInfo {
-    pub fn new<N: ThreadSafeLayoutNode>(node: &N,
+    pub fn new(data: HTMLCanvasData) -> CanvasFragmentInfo {
-                                        data: HTMLCanvasData,
-                                        ctx: &SharedStyleContext)
-                                        -> CanvasFragmentInfo {
         CanvasFragmentInfo {
-            replaced_image_fragment_info: ReplacedImageFragmentInfo::new(node, ctx),
             ipc_renderer: data.ipc_renderer
                               .map(|renderer| Arc::new(Mutex::new(renderer))),
             dom_width: Au::from_px(data.width as i32),
             dom_height: Au::from_px(data.height as i32),
         }
     }
-
-    /// Returns the original inline-size of the canvas.
-    pub fn canvas_inline_size(&self) -> Au {
-        if self.replaced_image_fragment_info.writing_mode_is_vertical {
-            self.dom_height
-        } else {
-            self.dom_width
-        }
-    }
-
-    /// Returns the original block-size of the canvas.
-    pub fn canvas_block_size(&self) -> Au {
-        if self.replaced_image_fragment_info.writing_mode_is_vertical {
-            self.dom_width
-        } else {
-            self.dom_height
-        }
-    }
 }
 
 #[derive(Clone)]
 pub struct SvgFragmentInfo {
-    pub replaced_image_fragment_info: ReplacedImageFragmentInfo,
     pub dom_width: Au,
     pub dom_height: Au,
 }
 
 impl SvgFragmentInfo {
-    pub fn new<N: ThreadSafeLayoutNode>(node: &N,
+    pub fn new(data: SVGSVGData) -> SvgFragmentInfo {
-                                        data: SVGSVGData,
-                                        ctx: &SharedStyleContext)
-                                        -> SvgFragmentInfo {
         SvgFragmentInfo {
-            replaced_image_fragment_info: ReplacedImageFragmentInfo::new(node, ctx),
             dom_width: Au::from_px(data.width as i32),
             dom_height: Au::from_px(data.height as i32),
         }
     }
-
-    /// Returns the original inline-size of the SVG element.
-    pub fn svg_inline_size(&self) -> Au {
-        if self.replaced_image_fragment_info.writing_mode_is_vertical {
-            self.dom_height
-        } else {
-            self.dom_width
-        }
-    }
-
-    /// Returns the original block-size of the SVG element.
-    pub fn svg_block_size(&self) -> Au {
-        if self.replaced_image_fragment_info.writing_mode_is_vertical {
-            self.dom_width
-        } else {
-            self.dom_height
-        }
-    }
 }
 
 
 /// A fragment that represents a replaced content image and its accompanying borders, shadows, etc.
 #[derive(Clone)]
 pub struct ImageFragmentInfo {
-    /// The image held within this fragment.
-    pub replaced_image_fragment_info: ReplacedImageFragmentInfo,
     pub image: Option<Arc<Image>>,
     pub metadata: Option<ImageMetadata>,
 }
@@ -418,7 +358,7 @@ impl ImageFragmentInfo {
     ///
     /// FIXME(pcwalton): The fact that image fragments store the cache in the fragment makes little
     /// sense to me.
-    pub fn new<N: ThreadSafeLayoutNode>(node: &N, url: Option<ServoUrl>,
+    pub fn new(url: Option<ServoUrl>,
                shared_layout_context: &SharedLayoutContext)
                -> ImageFragmentInfo {
         let image_or_metadata = url.and_then(|url| {
@@ -438,40 +378,11 @@ impl ImageFragmentInfo {
         };
 
         ImageFragmentInfo {
-            replaced_image_fragment_info: ReplacedImageFragmentInfo::new(node, &shared_layout_context.style_context),
             image: image,
             metadata: metadata,
         }
     }
 
-    /// Returns the original inline-size of the image.
-    pub fn image_inline_size(&mut self) -> Au {
-        match self.metadata {
-            Some(ref metadata) => {
-                Au::from_px(if self.replaced_image_fragment_info.writing_mode_is_vertical {
-                    metadata.height
-                } else {
-                    metadata.width
-                } as i32)
-            }
-            None => Au(0)
-        }
-    }
-
-    /// Returns the original block-size of the image.
-    pub fn image_block_size(&mut self) -> Au {
-        match self.metadata {
-            Some(ref metadata) => {
-                Au::from_px(if self.replaced_image_fragment_info.writing_mode_is_vertical {
-                    metadata.width
-                } else {
-                    metadata.height
-                } as i32)
-            }
-            None => Au(0)
-        }
-    }
-
     pub fn tile_image_round(position: &mut Au,
                             size: &mut Au,
                             absolute_anchor_origin: Au,
@@ -544,149 +455,6 @@ impl ImageFragmentInfo {
     }
 }
 
-#[derive(Clone)]
-pub struct ReplacedImageFragmentInfo {
-    pub computed_inline_size: Option<Au>,
-    pub computed_block_size: Option<Au>,
-    pub writing_mode_is_vertical: bool,
-}
-
-impl ReplacedImageFragmentInfo {
-    pub fn new<N>(node: &N, ctx: &SharedStyleContext) -> ReplacedImageFragmentInfo
-            where N: ThreadSafeLayoutNode {
-        let is_vertical = node.style(ctx).writing_mode.is_vertical();
-        ReplacedImageFragmentInfo {
-            computed_inline_size: None,
-            computed_block_size: None,
-            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!")
-    }
-
-    // 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,
-                        container_size: Option<Au>) -> MaybeAuto {
-        match (style_length, container_size) {
-            (LengthOrPercentageOrAuto::Length(length), _) => MaybeAuto::Specified(length),
-            (LengthOrPercentageOrAuto::Percentage(pc), Some(container_size)) => {
-                MaybeAuto::Specified(container_size.scale_by(pc))
-            }
-            (LengthOrPercentageOrAuto::Percentage(_), None) => MaybeAuto::Auto,
-            (LengthOrPercentageOrAuto::Calc(calc), Some(container_size)) => {
-                MaybeAuto::Specified(calc.length() + container_size.scale_by(calc.percentage()))
-            }
-            (LengthOrPercentageOrAuto::Calc(_), None) => MaybeAuto::Auto,
-            (LengthOrPercentageOrAuto::Auto, _) => MaybeAuto::Auto,
-        }
-    }
-
-    pub fn calculate_replaced_inline_size(&mut self,
-                                          style: &ServoComputedValues,
-                                          noncontent_inline_size: Au,
-                                          container_inline_size: Au,
-                                          container_block_size: Option<Au>,
-                                          fragment_inline_size: Au,
-                                          fragment_block_size: Au)
-                                          -> Au {
-        let style_inline_size = style.content_inline_size();
-        let style_block_size = style.content_block_size();
-        let style_min_inline_size = style.min_inline_size();
-        let style_max_inline_size = style.max_inline_size();
-        let style_min_block_size = style.min_block_size();
-        let style_max_block_size = style.max_block_size();
-
-        // TODO(ksh8281): compute border,margin
-        let inline_size = ReplacedImageFragmentInfo::style_length(
-            style_inline_size,
-            Some(container_inline_size));
-
-        let inline_size = match inline_size {
-            MaybeAuto::Auto => {
-                let intrinsic_width = fragment_inline_size;
-                let intrinsic_height = fragment_block_size;
-                if intrinsic_height == Au(0) {
-                    intrinsic_width
-                } else {
-                    let ratio = intrinsic_width.to_f32_px() /
-                                intrinsic_height.to_f32_px();
-
-                    let specified_height = ReplacedImageFragmentInfo::style_length(
-                        style_block_size,
-                        container_block_size);
-                    let specified_height = match specified_height {
-                        MaybeAuto::Auto => intrinsic_height,
-                        MaybeAuto::Specified(h) => h,
-                    };
-                    let specified_height = clamp_size(specified_height,
-                                                      style_min_block_size,
-                                                      style_max_block_size,
-                                                      Au(0));
-                    Au::from_f32_px(specified_height.to_f32_px() * ratio)
-                }
-            },
-            MaybeAuto::Specified(w) => w,
-        };
-
-        let inline_size = clamp_size(inline_size,
-                                     style_min_inline_size,
-                                     style_max_inline_size,
-                                     container_inline_size);
-
-        self.computed_inline_size = Some(inline_size);
-        inline_size + noncontent_inline_size
-    }
-
-    /// Here, `noncontent_block_size` represents the sum of border and padding, but not margin.
-    pub fn calculate_replaced_block_size(&mut self,
-                                         style: &ServoComputedValues,
-                                         noncontent_block_size: Au,
-                                         containing_block_block_size: Option<Au>,
-                                         fragment_inline_size: Au,
-                                         fragment_block_size: Au)
-                                         -> Au {
-        let style_block_size = style.content_block_size();
-        let style_min_block_size = style.min_block_size();
-        let style_max_block_size = style.max_block_size();
-
-        let inline_size = self.computed_inline_size();
-        let block_size = ReplacedImageFragmentInfo::style_length(
-            style_block_size,
-            containing_block_block_size);
-
-        let block_size = match block_size {
-            MaybeAuto::Auto => {
-                let intrinsic_width = fragment_inline_size;
-                let intrinsic_height = fragment_block_size;
-                let scale = intrinsic_width.to_f32_px() / inline_size.to_f32_px();
-                Au::from_f32_px(intrinsic_height.to_f32_px() / scale)
-            },
-            MaybeAuto::Specified(h) => {
-                h
-            }
-        };
-
-        let block_size = clamp_size(block_size,
-                                    style_min_block_size,
-                                    style_max_block_size,
-                                    Au(0));
-
-        self.computed_block_size = Some(block_size);
-        block_size + noncontent_block_size
-    }
-}
-
 /// 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 thread.
 #[derive(Clone)]
@@ -703,52 +471,6 @@ impl IframeFragmentInfo {
             pipeline_id: pipeline_id,
         }
     }
-
-    #[inline]
-    pub fn calculate_replaced_inline_size(&self, style: &ServoComputedValues, containing_size: Au)
-                                          -> Au {
-        // Calculate the replaced inline size (or default) as per CSS 2.1 § 10.3.2
-        IframeFragmentInfo::calculate_replaced_size(style.content_inline_size(),
-                                                    style.min_inline_size(),
-                                                    style.max_inline_size(),
-                                                    Some(containing_size),
-                                                    Au::from_px(300))
-    }
-
-    #[inline]
-    pub fn calculate_replaced_block_size(&self, style: &ServoComputedValues, containing_size: Option<Au>)
-                                         -> Au {
-        // Calculate the replaced block size (or default) as per CSS 2.1 § 10.3.2
-        IframeFragmentInfo::calculate_replaced_size(style.content_block_size(),
-                                                    style.min_block_size(),
-                                                    style.max_block_size(),
-                                                    containing_size,
-                                                    Au::from_px(150))
-
-    }
-
-    fn calculate_replaced_size(content_size: LengthOrPercentageOrAuto,
-                               style_min_size: LengthOrPercentage,
-                               style_max_size: LengthOrPercentageOrNone,
-                               containing_size: Option<Au>,
-                               default_size: Au) -> Au {
-        let computed_size = match (content_size, containing_size) {
-            (LengthOrPercentageOrAuto::Length(length), _) => length,
-            (LengthOrPercentageOrAuto::Percentage(pc), Some(container_size)) => container_size.scale_by(pc),
-            (LengthOrPercentageOrAuto::Calc(calc), Some(container_size)) => {
-                container_size.scale_by(calc.percentage()) + calc.length()
-            },
-            (LengthOrPercentageOrAuto::Calc(calc), None) => calc.length(),
-            (LengthOrPercentageOrAuto::Percentage(_), None) => default_size,
-            (LengthOrPercentageOrAuto::Auto, _) => default_size,
-        };
-
-        let containing_size = containing_size.unwrap_or(Au(0));
-        clamp_size(computed_size,
-                   style_min_size,
-                   style_max_size,
-                   containing_size)
-    }
 }
 
 /// A scanned text fragment represents a single run of text with a distinct style. A `TextFragment`
@@ -1202,6 +924,198 @@ impl Fragment {
         }
     }
 
+    /// intrinsic width of this replaced element.
+    #[inline]
+    pub fn intrinsic_width(&self) -> Au {
+        match self.specific {
+            SpecificFragmentInfo::Image(ref info) => {
+                if let Some(ref data) = info.metadata {
+                    Au::from_px(data.width as i32)
+                } else {
+                    Au(0)
+                }
+            }
+            SpecificFragmentInfo::Canvas(ref info) => info.dom_width,
+            SpecificFragmentInfo::Svg(ref info) => info.dom_width,
+            // Note: Currently for replaced element with no intrinsic size,
+            // this function simply returns the default object size. As long as
+            // these elements do not have intrinsic aspect ratio this should be
+            // sufficient, but we may need to investigate if this is enough for
+            // use cases like SVG.
+            SpecificFragmentInfo::Iframe(_) => Au::from_px(DEFAULT_REPLACED_WIDTH),
+            _ => panic!("Trying to get intrinsic width on non-replaced element!")
+        }
+    }
+
+    /// intrinsic width of this replaced element.
+    #[inline]
+    pub fn intrinsic_height(&self) -> Au {
+        match self.specific {
+            SpecificFragmentInfo::Image(ref info) => {
+                if let Some(ref data) = info.metadata {
+                    Au::from_px(data.height as i32)
+                } else {
+                    Au(0)
+                }
+            }
+            SpecificFragmentInfo::Canvas(ref info) => info.dom_height,
+            SpecificFragmentInfo::Svg(ref info) => info.dom_height,
+            SpecificFragmentInfo::Iframe(_) => Au::from_px(DEFAULT_REPLACED_HEIGHT),
+            _ => panic!("Trying to get intrinsic height on non-replaced element!")
+        }
+    }
+
+    /// Whether this replace element has intrinsic aspect ratio.
+    pub fn has_intrinsic_ratio(&self) -> bool {
+        match self.specific {
+            SpecificFragmentInfo::Image(_)  |
+            SpecificFragmentInfo::Canvas(_) |
+            // TODO(stshine): According to the SVG spec, whether a SVG element has intrinsic
+            // aspect ratio is determined by the `preserveAspectRatio` attribute. Since for
+            // now SVG is far from implemented, we simply choose the default behavior that
+            // the intrinsic aspect ratio is preserved.
+            // https://svgwg.org/svg2-draft/coords.html#PreserveAspectRatioAttribute
+            SpecificFragmentInfo::Svg(_) =>
+                self.intrinsic_width() != Au(0) && self.intrinsic_height() != Au(0),
+            _ => false
+        }
+    }
+
+    /// CSS 2.1 § 10.3.2 & 10.6.2 Calculate the used width and height of a replaced element.
+    /// When a parameter is `None` it means the specified size in certain direction
+    /// is unconstrained. The inline containing size can also be `None` since this
+    /// method is also used for calculating intrinsic inline size contribution.
+    pub fn calculate_replaced_sizes(&self,
+                                    containing_inline_size: Option<Au>,
+                                    containing_block_size: Option<Au>)
+                                    -> (Au, Au) {
+        let (intrinsic_inline_size, intrinsic_block_size) = if self.style.writing_mode.is_vertical() {
+            (self.intrinsic_height(), self.intrinsic_width())
+        } else {
+            (self.intrinsic_width(), self.intrinsic_height())
+        };
+
+        // Make sure the size we used here is for content box since they may be
+        // transferred by the intrinsic aspect ratio.
+        let inline_size = style_length(self.style.content_inline_size(), containing_inline_size)
+                                     .map(|x| x - self.box_sizing_boundary(Direction::Inline));
+        let block_size = style_length(self.style.content_block_size(), containing_block_size)
+                                     .map(|x| x - self.box_sizing_boundary(Direction::Block));
+        let inline_constraint = self.size_constraint(containing_inline_size, Direction::Inline);
+        let block_constraint = self.size_constraint(containing_block_size, Direction::Block);
+
+        // https://drafts.csswg.org/css-images-3/#default-sizing
+        match (inline_size, block_size) {
+            // If the specified size is a definite width and height, the concrete
+            // object size is given that width and height.
+            (MaybeAuto::Specified(inline_size), MaybeAuto::Specified(block_size)) =>
+                (inline_constraint.clamp(inline_size), block_constraint.clamp(block_size)),
+
+            // If the specified size is only a width or height (but not both)
+            // then the concrete object size is given that specified width or
+            // height. The other dimension is calculated as follows:
+            //
+            // If the object has an intrinsic aspect ratio, the missing dimension
+            // of the concrete object size is calculated using the intrinsic
+            // aspect ratio and the present dimension.
+            //
+            // Otherwise, if the missing dimension is present in the object’s intrinsic
+            // dimensions, the missing dimension is taken from the object’s intrinsic
+            // dimensions. Otherwise it is taken from the default object size.
+            (MaybeAuto::Specified(inline_size), MaybeAuto::Auto) => {
+                let inline_size = inline_constraint.clamp(inline_size);
+                let block_size = if self.has_intrinsic_ratio() {
+                    // Note: We can not precompute the ratio and store it as a float, because
+                    // doing so may result one pixel difference in calculation for certain
+                    // images, thus make some tests fail.
+                    inline_size * intrinsic_block_size.0 / intrinsic_inline_size.0
+                } else {
+                    intrinsic_block_size
+                };
+                (inline_size, block_constraint.clamp(block_size))
+            }
+            (MaybeAuto::Auto, MaybeAuto::Specified(block_size)) => {
+                let block_size = block_constraint.clamp(block_size);
+                let inline_size = if self.has_intrinsic_ratio() {
+                    block_size * intrinsic_inline_size.0 / intrinsic_block_size.0
+                } else {
+                    intrinsic_inline_size
+                };
+                (inline_constraint.clamp(inline_size), block_size)
+            }
+            // https://drafts.csswg.org/css2/visudet.html#min-max-widths
+            (MaybeAuto::Auto, MaybeAuto::Auto) => {
+                if self.has_intrinsic_ratio() {
+                    // This approch follows the spirit of cover and contain constraint.
+                    // https://drafts.csswg.org/css-images-3/#cover-contain
+
+                    // First, create two rectangles that keep aspect ratio while may be clamped
+                    // by the contraints;
+                    let first_isize = inline_constraint.clamp(intrinsic_inline_size);
+                    let first_bsize = first_isize * intrinsic_block_size.0 / intrinsic_inline_size.0;
+                    let second_bsize = block_constraint.clamp(intrinsic_block_size);
+                    let second_isize = second_bsize * intrinsic_inline_size.0 / intrinsic_block_size.0;
+
+                    let (inline_size, block_size) = match (first_isize.cmp(&intrinsic_inline_size) ,
+                                                           second_isize.cmp(&intrinsic_inline_size)) {
+                        (Ordering::Equal, Ordering::Equal) =>
+                            (first_isize, first_bsize),
+                        // When only one rectangle is clamped, use it;
+                        (Ordering::Equal, _) =>
+                            (second_isize, second_bsize),
+                        (_, Ordering::Equal) =>
+                            (first_isize, first_bsize),
+                        // When both rectangles grow (smaller than min sizes),
+                        // Choose the larger one;
+                        (Ordering::Greater, Ordering::Greater) =>
+                            if first_isize > second_isize {
+                                (first_isize, first_bsize)
+                            } else {
+                                (second_isize, second_bsize)
+                            },
+                        // When both rectangles shrink (larger than max sizes),
+                        // Choose the smaller one;
+                        (Ordering::Less, Ordering::Less) =>
+                            if first_isize > second_isize {
+                                (second_isize, second_bsize)
+                            } else {
+                                (first_isize, first_bsize)
+                            },
+                        // It does not matter which we choose here, because both sizes
+                        // will be clamped to constraint;
+                        (Ordering::Less, Ordering::Greater) | (Ordering::Greater, Ordering::Less) =>
+                            (first_isize, first_bsize)
+                    };
+                    // Clamp the result and we are done :-)
+                    (inline_constraint.clamp(inline_size), block_constraint.clamp(block_size))
+                } else {
+                    (inline_constraint.clamp(intrinsic_inline_size),
+                    block_constraint.clamp(intrinsic_block_size))
+                }
+            }
+        }
+    }
+
+    /// Return a size constraint that can be used the clamp size in given direction.
+    /// To take `box-sizing: border-box` into account, the `border_padding` field
+    /// must be initialized first.
+    ///
+    /// TODO(stshine): Maybe there is a more convenient way.
+    pub fn size_constraint(&self, containing_size: Option<Au>, direction: Direction) -> SizeConstraint {
+        let (style_min_size, style_max_size) = match direction {
+            Direction::Inline => (self.style.min_inline_size(), self.style.max_inline_size()),
+            Direction::Block => (self.style.min_block_size(), self.style.max_block_size())
+        };
+
+        let border = if self.style().get_position().box_sizing == box_sizing::T::border_box {
+            Some(self.border_padding.start_end(direction))
+        } else {
+            None
+        };
+
+        SizeConstraint::new(containing_size, style_min_size, style_max_size, border)
+    }
+
     /// Returns a guess as to the distances from the margin edge of this fragment to its content
     /// in the inline direction. This will generally be correct unless percentages are involved.
     ///
@@ -1254,7 +1168,7 @@ impl Fragment {
     }
 
     /// Returns the border width in given direction if this fragment has property
-    /// 'box-sizing: border-box'. The `border_padding` field should have been initialized.
+    /// 'box-sizing: border-box'. The `border_padding` field must have been initialized.
     pub fn box_sizing_boundary(&self, direction: Direction) -> Au {
         match (self.style().get_position().box_sizing, direction) {
             (box_sizing::T::border_box, Direction::Inline) => {
@@ -1531,7 +1445,6 @@ impl Fragment {
         match self.specific {
             SpecificFragmentInfo::Generic |
             SpecificFragmentInfo::GeneratedContent(_) |
-            SpecificFragmentInfo::Iframe(_) |
             SpecificFragmentInfo::Table |
             SpecificFragmentInfo::TableCell |
             SpecificFragmentInfo::TableColumn(_) |
@@ -1548,66 +1461,42 @@ impl Fragment {
                 let block_flow = info.flow_ref.as_block();
                 result.union_block(&block_flow.base.intrinsic_inline_sizes)
             }
-            SpecificFragmentInfo::Image(ref mut image_fragment_info) => {
+            SpecificFragmentInfo::Image(_) |
-                let mut image_inline_size = match self.style.content_inline_size() {
+            SpecificFragmentInfo::Canvas(_) |
+            SpecificFragmentInfo::Iframe(_) |
+            SpecificFragmentInfo::Svg(_) => {
+                let mut inline_size = match self.style.content_inline_size() {
                     LengthOrPercentageOrAuto::Auto |
                     LengthOrPercentageOrAuto::Percentage(_) => {
-                        image_fragment_info.image_inline_size()
+                        // We have to initialize the `border_padding` field first to make
+                        // the size constraints work properly.
+                        // TODO(stshine): Find a cleaner way to do this.
+                        let padding = self.style.logical_padding();
+                        self.border_padding.inline_start = model::specified(padding.inline_start, Au(0));
+                        self.border_padding.inline_end = model::specified(padding.inline_end, Au(0));
+                        self.border_padding.block_start = model::specified(padding.block_start, Au(0));
+                        self.border_padding.block_end = model::specified(padding.block_end, Au(0));
+                        let border = self.border_width();
+                        self.border_padding.inline_start += border.inline_start;
+                        self.border_padding.inline_end += border.inline_end;
+                        self.border_padding.block_start += border.block_start;
+                        self.border_padding.block_end += border.block_end;
+                        let (result_inline, _) = self.calculate_replaced_sizes(None, None);
+                        result_inline
                     }
                     LengthOrPercentageOrAuto::Length(length) => length,
                     LengthOrPercentageOrAuto::Calc(calc) => calc.length(),
                 };
 
-                image_inline_size = max(model::specified(self.style.min_inline_size(), Au(0)), image_inline_size);
+                let size_constraint = self.size_constraint(None, Direction::Inline);
-                if let Some(max) = model::specified_or_none(self.style.max_inline_size(), Au(0)) {
+                inline_size = size_constraint.clamp(inline_size);
-                    image_inline_size = min(image_inline_size, max)
-                }
 
                 result.union_block(&IntrinsicISizes {
-                    minimum_inline_size: image_inline_size,
+                    minimum_inline_size: inline_size,
-                    preferred_inline_size: image_inline_size,
+                    preferred_inline_size: inline_size,
                 });
             }
-            SpecificFragmentInfo::Canvas(ref mut canvas_fragment_info) => {
-                let mut canvas_inline_size = match self.style.content_inline_size() {
-                    LengthOrPercentageOrAuto::Auto |
-                    LengthOrPercentageOrAuto::Percentage(_) => {
-                        canvas_fragment_info.canvas_inline_size()
-                    }
-                    LengthOrPercentageOrAuto::Length(length) => length,
-                    LengthOrPercentageOrAuto::Calc(calc) => calc.length(),
-                };
 
-                canvas_inline_size = max(model::specified(self.style.min_inline_size(), Au(0)), canvas_inline_size);
-                if let Some(max) = model::specified_or_none(self.style.max_inline_size(), Au(0)) {
-                    canvas_inline_size = min(canvas_inline_size, max)
-                }
-
-                result.union_block(&IntrinsicISizes {
-                    minimum_inline_size: canvas_inline_size,
-                    preferred_inline_size: canvas_inline_size,
-                });
-            }
-            SpecificFragmentInfo::Svg(ref mut svg_fragment_info) => {
-                let mut svg_inline_size = match self.style.content_inline_size() {
-                    LengthOrPercentageOrAuto::Auto |
-                    LengthOrPercentageOrAuto::Percentage(_) => {
-                        svg_fragment_info.svg_inline_size()
-                    }
-                    LengthOrPercentageOrAuto::Length(length) => length,
-                    LengthOrPercentageOrAuto::Calc(calc) => calc.length(),
-                };
-
-                svg_inline_size = max(model::specified(self.style.min_inline_size(), Au(0)), svg_inline_size);
-                if let Some(max) = model::specified_or_none(self.style.max_inline_size(), Au(0)) {
-                    svg_inline_size = min(svg_inline_size, max)
-                }
-
-                result.union_block(&IntrinsicISizes {
-                    minimum_inline_size: svg_inline_size,
-                    preferred_inline_size: svg_inline_size,
-                });
-            }
             SpecificFragmentInfo::ScannedText(ref text_fragment_info) => {
                 let range = &text_fragment_info.range;
 
@@ -1676,45 +1565,6 @@ impl Fragment {
         }
     }
 
-    /// TODO: What exactly does this function return? Why is it Au(0) for
-    /// `SpecificFragmentInfo::Generic`?
-    pub fn content_inline_size(&self) -> Au {
-        match self.specific {
-            SpecificFragmentInfo::Generic |
-            SpecificFragmentInfo::GeneratedContent(_) |
-            SpecificFragmentInfo::Iframe(_) |
-            SpecificFragmentInfo::Table |
-            SpecificFragmentInfo::TableCell |
-            SpecificFragmentInfo::TableRow |
-            SpecificFragmentInfo::TableWrapper |
-            SpecificFragmentInfo::Multicol |
-            SpecificFragmentInfo::MulticolColumn |
-            SpecificFragmentInfo::InlineBlock(_) |
-            SpecificFragmentInfo::InlineAbsoluteHypothetical(_) |
-            SpecificFragmentInfo::InlineAbsolute(_) => Au(0),
-            SpecificFragmentInfo::Canvas(ref canvas_fragment_info) => {
-                canvas_fragment_info.replaced_image_fragment_info.computed_inline_size()
-            }
-            SpecificFragmentInfo::Svg(ref svg_fragment_info) => {
-                svg_fragment_info.replaced_image_fragment_info.computed_inline_size()
-            }
-            SpecificFragmentInfo::Image(ref image_fragment_info) => {
-                image_fragment_info.replaced_image_fragment_info.computed_inline_size()
-            }
-            SpecificFragmentInfo::ScannedText(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
-            }
-            SpecificFragmentInfo::TableColumn(_) => {
-                panic!("Table column fragments do not have inline_size")
-            }
-            SpecificFragmentInfo::UnscannedText(_) => {
-                panic!("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
@@ -1991,10 +1841,8 @@ impl Fragment {
             SpecificFragmentInfo::Svg(_) => {}
         };
 
-        let style = &*self.style;
-        let noncontent_inline_size = self.border_padding.inline_start_end();
-
         match self.specific {
+            // Inline blocks
             SpecificFragmentInfo::InlineAbsoluteHypothetical(ref mut info) => {
                 let block_flow = FlowRef::deref_mut(&mut info.flow_ref).as_mut_block();
                 block_flow.base.position.size.inline =
@@ -2019,54 +1867,24 @@ impl Fragment {
                 block_flow.base.block_container_inline_size = self.border_box.size.inline;
                 block_flow.base.block_container_writing_mode = self.style.writing_mode;
             }
+
+            // Text
             SpecificFragmentInfo::ScannedText(ref info) => {
                 // Scanned text fragments will have already had their content inline-sizes assigned
                 // by this point.
-                self.border_box.size.inline = info.content_size.inline + noncontent_inline_size
+                self.border_box.size.inline = info.content_size.inline +
+                    self.border_padding.inline_start_end();
             }
-            SpecificFragmentInfo::Image(ref mut image_fragment_info) => {
+
-                let fragment_inline_size = image_fragment_info.image_inline_size();
+            // Replaced elements
-                let fragment_block_size = image_fragment_info.image_block_size();
+            _ if self.is_replaced() => {
-                self.border_box.size.inline =
+                let (inline_size, block_size) =
-                    image_fragment_info.replaced_image_fragment_info
+                    self.calculate_replaced_sizes(Some(container_inline_size), container_block_size);
-                                       .calculate_replaced_inline_size(style,
+                self.border_box.size.inline = inline_size + self.border_padding.inline_start_end();
-                                                                       noncontent_inline_size,
+                self.border_box.size.block = block_size + self.border_padding.block_start_end();
-                                                                       container_inline_size,
-                                                                       container_block_size,
-                                                                       fragment_inline_size,
-                                                                       fragment_block_size);
             }
-            SpecificFragmentInfo::Canvas(ref mut canvas_fragment_info) => {
+
-                let fragment_inline_size = canvas_fragment_info.canvas_inline_size();
+            ref unhandled @ _ => panic!("this case should have been handled above: {:?}", unhandled),
-                let fragment_block_size = canvas_fragment_info.canvas_block_size();
-                self.border_box.size.inline =
-                    canvas_fragment_info.replaced_image_fragment_info
-                                        .calculate_replaced_inline_size(style,
-                                                                        noncontent_inline_size,
-                                                                        container_inline_size,
-                                                                        container_block_size,
-                                                                        fragment_inline_size,
-                                                                        fragment_block_size);
-            }
-            SpecificFragmentInfo::Svg(ref mut svg_fragment_info) => {
-                let fragment_inline_size = svg_fragment_info.svg_inline_size();
-                let fragment_block_size = svg_fragment_info.svg_block_size();
-                self.border_box.size.inline =
-                    svg_fragment_info.replaced_image_fragment_info
-                                        .calculate_replaced_inline_size(style,
-                                                                        noncontent_inline_size,
-                                                                        container_inline_size,
-                                                                        container_block_size,
-                                                                        fragment_inline_size,
-                                                                        fragment_block_size);
-            }
-            SpecificFragmentInfo::Iframe(ref iframe_fragment_info) => {
-                self.border_box.size.inline =
-                    iframe_fragment_info.calculate_replaced_inline_size(style,
-                                                                        container_inline_size) +
-                                              noncontent_inline_size;
-            }
-            _ => panic!("this case should have been handled above"),
         }
     }
 
@@ -2074,7 +1892,7 @@ impl Fragment {
     /// 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: Option<Au>) {
+    pub fn assign_replaced_block_size_if_necessary(&mut self) {
         match self.specific {
             SpecificFragmentInfo::Generic |
             SpecificFragmentInfo::GeneratedContent(_) |
@@ -2100,48 +1918,16 @@ impl Fragment {
             SpecificFragmentInfo::Svg(_) => {}
         }
 
-        let style = &*self.style;
-        let noncontent_block_size = self.border_padding.block_start_end();
-
         match self.specific {
-            SpecificFragmentInfo::Image(ref mut image_fragment_info) => {
+            // Text
-                let fragment_inline_size = image_fragment_info.image_inline_size();
-                let fragment_block_size = image_fragment_info.image_block_size();
-                self.border_box.size.block =
-                    image_fragment_info.replaced_image_fragment_info
-                                       .calculate_replaced_block_size(style,
-                                                                      noncontent_block_size,
-                                                                      containing_block_block_size,
-                                                                      fragment_inline_size,
-                                                                      fragment_block_size);
-            }
-            SpecificFragmentInfo::Canvas(ref mut canvas_fragment_info) => {
-                let fragment_inline_size = canvas_fragment_info.canvas_inline_size();
-                let fragment_block_size = canvas_fragment_info.canvas_block_size();
-                self.border_box.size.block =
-                    canvas_fragment_info.replaced_image_fragment_info
-                                        .calculate_replaced_block_size(style,
-                                                                       noncontent_block_size,
-                                                                       containing_block_block_size,
-                                                                       fragment_inline_size,
-                                                                       fragment_block_size);
-            }
-            SpecificFragmentInfo::Svg(ref mut svg_fragment_info) => {
-                let fragment_inline_size = svg_fragment_info.svg_inline_size();
-                let fragment_block_size = svg_fragment_info.svg_block_size();
-                self.border_box.size.block =
-                    svg_fragment_info.replaced_image_fragment_info
-                                        .calculate_replaced_block_size(style,
-                                                                       noncontent_block_size,
-                                                                       containing_block_block_size,
-                                                                       fragment_inline_size,
-                                                                       fragment_block_size);
-            }
             SpecificFragmentInfo::ScannedText(ref info) => {
                 // Scanned text fragments' content block-sizes are calculated by the text run
                 // scanner during flow construction.
-                self.border_box.size.block = info.content_size.block + noncontent_block_size
+                self.border_box.size.block = info.content_size.block +
+                    self.border_padding.block_start_end();
             }
+
+            // Inline blocks
             SpecificFragmentInfo::InlineBlock(ref mut info) => {
                 // Not the primary fragment, so we do not take the noncontent size into account.
                 let block_flow = FlowRef::deref_mut(&mut info.flow_ref).as_block();
@@ -2159,36 +1945,31 @@ impl Fragment {
                 self.border_box.size.block = block_flow.base.position.size.block +
                     block_flow.fragment.margin.block_start_end()
             }
-            SpecificFragmentInfo::Iframe(ref info) => {
+
-                self.border_box.size.block =
+            // Replaced elements
-                    info.calculate_replaced_block_size(style, containing_block_block_size) +
+            _ if self.is_replaced() => {},
-                    noncontent_block_size;
+
+            ref unhandled @ _ => panic!("should have been handled above: {:?}", unhandled),
         }
-            _ => panic!("should have been handled above"),
+    }
+
+    /// Returns true if this fragment is replaced content.
+    pub fn is_replaced(&self) -> bool {
+        match self.specific {
+            SpecificFragmentInfo::Iframe(_) |
+            SpecificFragmentInfo::Canvas(_) |
+            SpecificFragmentInfo::Image(_) |
+            SpecificFragmentInfo::Svg(_) => true,
+            _ => false
         }
     }
 
     /// Returns true if this fragment is replaced content or an inline-block or false otherwise.
     pub fn is_replaced_or_inline_block(&self) -> bool {
         match self.specific {
-            SpecificFragmentInfo::Canvas(_) |
-            SpecificFragmentInfo::Iframe(_) |
-            SpecificFragmentInfo::Image(_) |
             SpecificFragmentInfo::InlineAbsoluteHypothetical(_) |
-            SpecificFragmentInfo::InlineBlock(_) |
+            SpecificFragmentInfo::InlineBlock(_) => true,
-            SpecificFragmentInfo::Svg(_) => true,
+            _ => self.is_replaced(),
-            SpecificFragmentInfo::Generic |
-            SpecificFragmentInfo::GeneratedContent(_) |
-            SpecificFragmentInfo::InlineAbsolute(_) |
-            SpecificFragmentInfo::Table |
-            SpecificFragmentInfo::TableCell |
-            SpecificFragmentInfo::TableColumn(_) |
-            SpecificFragmentInfo::TableRow |
-            SpecificFragmentInfo::TableWrapper |
-            SpecificFragmentInfo::Multicol |
-            SpecificFragmentInfo::MulticolColumn |
-            SpecificFragmentInfo::ScannedText(_) |
-            SpecificFragmentInfo::UnscannedText(_) => false,
         }
     }
 
@@ -2209,10 +1990,10 @@ impl Fragment {
             SpecificFragmentInfo::Canvas(_) | SpecificFragmentInfo::Iframe(_) |
             SpecificFragmentInfo::Image(_) | SpecificFragmentInfo::Svg(_) |
             SpecificFragmentInfo::Generic | SpecificFragmentInfo::GeneratedContent(_) => {
-                let ascent = self.border_box.size.block + self.margin.block_start;
+                let ascent = self.border_box.size.block + self.margin.block_end;
                 InlineMetrics {
-                    space_above_baseline: ascent,
+                    space_above_baseline: ascent + self.margin.block_start,
-                    space_below_baseline: self.margin.block_end,
+                    space_below_baseline: Au(0),
                     ascent: ascent,
                 }
             }

components/layout/inline.rs

@@ -1394,11 +1394,9 @@ impl Flow for InlineFlow {
         debug!("assign_block_size_inline: floats in: {:?}", self.base.floats);
 
         // Assign the block-size and late-computed inline-sizes for the inline fragments.
-        let containing_block_block_size =
-            self.base.block_container_explicit_block_size;
         for fragment in &mut self.fragments.fragments {
             fragment.update_late_computed_replaced_inline_size_if_necessary();
-            fragment.assign_replaced_block_size_if_necessary(containing_block_block_size);
+            fragment.assign_replaced_block_size_if_necessary();
         }
 
         // Reset our state, so that we handle incremental reflow correctly.

components/layout/list_item.rs

@@ -111,9 +111,7 @@ impl Flow for ListItemFlow {
                                                            &mut layout_context.font_context(),
                                                            &*self.block_flow.fragment.style);
         for marker in &mut self.marker_fragments {
-            let containing_block_block_size =
+            marker.assign_replaced_block_size_if_necessary();
-                self.block_flow.base.block_container_explicit_block_size;
-            marker.assign_replaced_block_size_if_necessary(containing_block_block_size);
             let marker_inline_metrics = marker.aligned_inline_metrics(layout_context,
                                                                       &marker_line_metrics,
                                                                       Some(&marker_line_metrics));

components/layout/model.rs

@@ -436,6 +436,21 @@ impl MaybeAuto {
     }
 }
 
+/// Receive an optional container size and return used value for width or height.
+///
+/// `style_length`: content size as given in the CSS.
+pub fn style_length(style_length: LengthOrPercentageOrAuto,
+                    container_size: Option<Au>) -> MaybeAuto {
+    match container_size {
+        Some(length) => MaybeAuto::from_style(style_length, length),
+        None => if let LengthOrPercentageOrAuto::Length(length) = style_length {
+            MaybeAuto::Specified(length)
+        } else {
+            MaybeAuto::Auto
+        }
+    }
+}
+
 pub fn specified_or_none(length: LengthOrPercentageOrNone, containing_length: Au) -> Option<Au> {
     match length {
         LengthOrPercentageOrNone::None => None,
@@ -504,64 +519,60 @@ impl ToGfxMatrix for ComputedMatrix {
     }
 }
 
-// https://drafts.csswg.org/css2/visudet.html#min-max-widths
+/// A min-size and max-size constraint. The constructor has a optional `border`
-// https://drafts.csswg.org/css2/visudet.html#min-max-heights
+/// parameter, and when it is present the constraint will be subtracted. This is
-/// A min or max constraint
+/// used to adjust the constraint for `box-sizing: border-box`, and when you do so
-///
+/// make sure the size you want to clamp is intended to be used for content box.
-/// A `max` of `None` is equivalent to no limmit for the size in the given
+#[derive(Clone, Copy, Debug)]
-/// dimension. The `min` is >= 0, as negative values are illegal and by
+pub struct SizeConstraint {
-/// default `min` is 0.
+    min_size: Au,
-#[derive(Debug)]
+    max_size: Option<Au>,
-pub struct MinMaxConstraint {
-    min: Au,
-    max: Option<Au>
 }
 
-impl MinMaxConstraint {
+impl SizeConstraint {
-    /// Create a `MinMaxConstraint` for a dimension given the min, max, and content box size for
+    /// Create a `SizeConstraint` for an axis.
-    /// an axis
+    pub fn new(container_size: Option<Au>,
-    pub fn new(content_size: Option<Au>, min: LengthOrPercentage,
+               min_size: LengthOrPercentage,
-               max: LengthOrPercentageOrNone) -> MinMaxConstraint {
+               max_size: LengthOrPercentageOrNone,
-        let min = match min {
+               border: Option<Au>) -> SizeConstraint {
-            LengthOrPercentage::Length(length) => length,
+        let mut min_size = match container_size {
-            LengthOrPercentage::Percentage(percent) => {
+            Some(container_size) => specified(min_size, container_size),
-                match content_size {
+            None => if let LengthOrPercentage::Length(length) = min_size {
-                    Some(size) => size.scale_by(percent),
+                length
-                    None => Au(0),
-                }
-            },
-            LengthOrPercentage::Calc(calc) => {
-                match content_size {
-                    Some(size) => size.scale_by(calc.percentage()),
-                    None => Au(0),
-                }
-            }
-        };
-
-        let max = match max {
-            LengthOrPercentageOrNone::Length(length) => Some(length),
-            LengthOrPercentageOrNone::Percentage(percent) => {
-                content_size.map(|size| size.scale_by(percent))
-            },
-            LengthOrPercentageOrNone::Calc(calc) => {
-                content_size.map(|size| size.scale_by(calc.percentage()))
-            }
-            LengthOrPercentageOrNone::None => None,
-        };
-
-        MinMaxConstraint {
-            min: min,
-            max: max
-        }
-    }
-
-    /// Clamp the given size by the given `min` and `max` constraints.
-    pub fn clamp(&self, other: Au) -> Au {
-        if other < self.min {
-            self.min
             } else {
-            match self.max {
+                Au(0)
-                Some(max) if max < other => max,
+            }
+        };
+
+        let mut max_size = match container_size {
+            Some(container_size) => specified_or_none(max_size, container_size),
+            None => if let LengthOrPercentageOrNone::Length(length) = max_size {
+                Some(length)
+            } else {
+                None
+            }
+        };
+        // Make sure max size is not smaller than min size.
+        max_size = max_size.map(|x| max(x, min_size));
+
+        if let Some(border) = border {
+            min_size = max((min_size - border), Au(0));
+            max_size = max_size.map(|x| max(x - border, Au(0)));
+        }
+
+        SizeConstraint {
+            min_size: min_size,
+            max_size: max_size
+        }
+    }
+
+    /// Clamp the given size by the given min size and max size constraint.
+    pub fn clamp(&self, other: Au) -> Au {
+        if other < self.min_size {
+            self.min_size
+        } else {
+            match self.max_size {
+                Some(max_size) if max_size < other => max_size,
                 _ => other
             }
         }

tests/wpt/metadata-css/css21_dev/html4/block-replaced-height-004.htm.ini

@@ -1,3 +0,0 @@
-[block-replaced-height-004.htm]
-  type: reftest
-  expected: FAIL

tests/wpt/metadata-css/css21_dev/html4/block-replaced-height-005.htm.ini

@@ -1,3 +0,0 @@
-[block-replaced-height-005.htm]
-  type: reftest
-  expected: FAIL

tests/wpt/metadata-css/css21_dev/html4/block-replaced-height-007.htm.ini

@@ -1,3 +0,0 @@
-[block-replaced-height-007.htm]
-  type: reftest
-  expected: FAIL

tests/wpt/metadata-css/css21_dev/html4/c43-rpl-bbx-002.htm.ini

@@ -1,3 +0,0 @@
-[c43-rpl-bbx-002.htm]
-  type: reftest
-  expected: FAIL

tests/wpt/metadata-css/css21_dev/html4/c44-ln-box-003.htm.ini

@@ -1,3 +0,0 @@
-[c44-ln-box-003.htm]
-  type: reftest
-  expected: FAIL

tests/wpt/metadata-css/css21_dev/html4/float-replaced-height-004.htm.ini

@@ -1,3 +0,0 @@
-[float-replaced-height-004.htm]
-  type: reftest
-  expected: FAIL

tests/wpt/metadata-css/css21_dev/html4/float-replaced-height-005.htm.ini

@@ -1,3 +0,0 @@
-[float-replaced-height-005.htm]
-  type: reftest
-  expected: FAIL

tests/wpt/metadata-css/css21_dev/html4/float-replaced-height-007.htm.ini

@@ -1,3 +0,0 @@
-[float-replaced-height-007.htm]
-  type: reftest
-  expected: FAIL

tests/wpt/metadata-css/css21_dev/html4/inline-block-replaced-height-004.htm.ini

@@ -1,3 +0,0 @@
-[inline-block-replaced-height-004.htm]
-  type: reftest
-  expected: FAIL

tests/wpt/metadata-css/css21_dev/html4/inline-block-replaced-height-005.htm.ini

@@ -1,3 +0,0 @@
-[inline-block-replaced-height-005.htm]
-  type: reftest
-  expected: FAIL

tests/wpt/metadata-css/css21_dev/html4/inline-block-replaced-height-007.htm.ini

@@ -1,3 +0,0 @@
-[inline-block-replaced-height-007.htm]
-  type: reftest
-  expected: FAIL

tests/wpt/metadata-css/css21_dev/html4/max-height-percentage-003.htm.ini

@@ -1,3 +0,0 @@
-[max-height-percentage-003.htm]
-  type: reftest
-  expected: FAIL