servo: Merge #3286 - Implement basic support for display: inline-block (from glennw:inline_block)

Source-Repo: https://github.com/servo/servo
Source-Revision: b64f27b2b69996508eed0a76acc7414a791b1a9e

servo/components/layout/block.rs

@@ -20,7 +20,7 @@ use floats::{ClearBoth, ClearLeft, ClearRight, FloatKind, Floats, PlacementInfo}
 use flow::{BaseFlow, BlockFlowClass, FlowClass, Flow, ImmutableFlowUtils};
 use flow::{MutableFlowUtils, PreorderFlowTraversal, PostorderFlowTraversal, mut_base};
 use flow;
-use fragment::{Fragment, ImageFragment, ScannedTextFragment};
+use fragment::{Fragment, ImageFragment, InlineBlockFragment, ScannedTextFragment};
 use layout_debug;
 use model::{Auto, IntrinsicISizes, MarginCollapseInfo, MarginsCollapse};
 use model::{MarginsCollapseThrough, MaybeAuto, NoCollapsibleMargins, Specified, specified};
@@ -706,7 +706,7 @@ impl BlockFlow {
     /// and image fragments.
     fn is_replaced_content(&self) -> bool {
         match self.fragment.specific {
-            ScannedTextFragment(_) | ImageFragment(_) => true,
+            ScannedTextFragment(_) | ImageFragment(_) | InlineBlockFragment(_) => true,
             _ => false,
         }
     }

servo/components/layout/construct.rs

@@ -27,6 +27,7 @@ use flow::{Flow, ImmutableFlowUtils, MutableOwnedFlowUtils};
 use flow::{Descendants, AbsDescendants};
 use flow;
 use flow_ref::FlowRef;
+use fragment::{InlineBlockFragment, InlineBlockFragmentInfo};
 use fragment::{Fragment, GenericFragment, IframeFragment, IframeFragmentInfo};
 use fragment::{ImageFragment, ImageFragmentInfo, SpecificFragmentInfo, TableFragment};
 use fragment::{TableCellFragment, TableColumnFragment, TableColumnFragmentInfo};
@@ -266,19 +267,38 @@ impl<'a, 'b> FlowConstructor<'a, 'b> {
             }
         }
 
-        let mut inline_flow = box InlineFlow::from_fragments((*node).clone(), fragments);
-        let (ascent, descent) = inline_flow.compute_minimum_ascent_and_descent(self.layout_context.font_context(), &**node.style());
-        inline_flow.minimum_block_size_above_baseline = ascent;
-        inline_flow.minimum_depth_below_baseline = descent;
-        let mut inline_flow = inline_flow as Box<Flow>;
-        TextRunScanner::new().scan_for_runs(self.layout_context.font_context(), inline_flow);
-        let mut inline_flow = FlowRef::new(inline_flow);
-        inline_flow.finish(self.layout_context);
+        // Build a list of all the inline-block fragments before fragments is moved.
+        let mut inline_block_flows = vec!();
+        for f in fragments.fragments.iter() {
+            match f.specific {
+                InlineBlockFragment(ref info) => {
+                    inline_block_flows.push(info.flow_ref.clone());
+                },
+                _ => {}
+            }
+        }
 
-        if flow.get().need_anonymous_flow(inline_flow.get()) {
-            flow_list.push(inline_flow)
+        let mut inline_flow_ref = FlowRef::new(box InlineFlow::from_fragments((*node).clone(), fragments));
+
+        // Add all the inline-block fragments as children of the inline flow.
+        for inline_block_flow in inline_block_flows.iter() {
+            inline_flow_ref.add_new_child(inline_block_flow.clone());
+        }
+
+        {
+            let mut inline_flow = inline_flow_ref.get_mut().as_inline();
+            let (ascent, descent) = inline_flow.compute_minimum_ascent_and_descent(self.layout_context.font_context(), &**node.style());
+            inline_flow.minimum_block_size_above_baseline = ascent;
+            inline_flow.minimum_depth_below_baseline = descent;
+            TextRunScanner::new().scan_for_runs(self.layout_context.font_context(), inline_flow);
+        }
+
+        inline_flow_ref.finish(self.layout_context);
+
+        if flow.get().need_anonymous_flow(inline_flow_ref.get()) {
+            flow_list.push(inline_flow_ref)
         } else {
-            flow.add_new_child(inline_flow)
+            flow.add_new_child(inline_flow_ref)
         }
     }
 
@@ -582,6 +602,27 @@ impl<'a, 'b> FlowConstructor<'a, 'b> {
         ConstructionItemConstructionResult(construction_item)
     }
 
+    fn build_fragment_for_inline_block(&mut self, node: &ThreadSafeLayoutNode) -> ConstructionResult {
+        let block_flow_result = self.build_flow_for_block(node);
+        let block_flow = match block_flow_result {
+            FlowConstructionResult(block_flow, _) => block_flow,
+            _ => unreachable!()
+        };
+
+        let fragment_info = InlineBlockFragment(InlineBlockFragmentInfo::new(block_flow));
+        let mut fragment = Fragment::new_from_specific_info(node, fragment_info);
+
+        let mut fragment_accumulator = InlineFragmentsAccumulator::from_inline_node(node);
+        fragment_accumulator.fragments.push(&mut fragment, node.style().clone());
+
+        let construction_item = InlineFragmentsConstructionItem(InlineFragmentsConstructionResult {
+            splits: Vec::new(),
+            fragments: fragment_accumulator.finish(),
+            abs_descendants: Descendants::new(),
+        });
+        ConstructionItemConstructionResult(construction_item)
+    }
+
     /// Builds one or more fragments for a node with `display: inline`. This yields an
     /// `InlineFragmentsConstructionResult`.
     fn build_fragments_for_inline(&mut self, node: &ThreadSafeLayoutNode) -> ConstructionResult {
@@ -840,6 +881,12 @@ impl<'a, 'b> PostorderNodeMutTraversal for FlowConstructor<'a, 'b> {
                 node.set_flow_construction_result(construction_result)
             }
 
+            // Inline-block items contribute inline fragment construction results.
+            (display::inline_block, float::none, _) => {
+                let construction_result = self.build_fragment_for_inline_block(node);
+                node.set_flow_construction_result(construction_result)
+            }
+
             // Table items contribute table flow construction results.
             (display::table_caption, _, _) => {
                 let construction_result = self.build_flow_for_table_caption(node);

servo/components/layout/fragment.rs

@@ -10,8 +10,9 @@ use css::node_style::StyledNode;
 use construct::FlowConstructor;
 use context::LayoutContext;
 use floats::{ClearBoth, ClearLeft, ClearRight, ClearType};
-use flow::Flow;
+use flow::{Flow, MutableFlowUtils};
 use flow;
+use flow_ref::FlowRef;
 use inline::{InlineFragmentContext, InlineMetrics};
 use layout_debug;
 use model::{Auto, IntrinsicISizes, MaybeAuto, Specified, specified};
@@ -125,6 +126,7 @@ impl<E, S: Encoder<E>> Encodable<S, E> for Fragment {
 /// Info specific to the kind of fragment. Keep this enum small.
 #[deriving(Clone)]
 pub enum SpecificFragmentInfo {
+    InlineBlockFragment(InlineBlockFragmentInfo),
     GenericFragment,
     ImageFragment(ImageFragmentInfo),
     IframeFragment(IframeFragmentInfo),
@@ -137,6 +139,20 @@ pub enum SpecificFragmentInfo {
     UnscannedTextFragment(UnscannedTextFragmentInfo),
 }
 
+/// A fragment that represents an inline-block element.
+#[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 {
@@ -454,7 +470,7 @@ impl Fragment {
     /// replaced elements.
     fn style_specified_intrinsic_inline_size(&self) -> IntrinsicISizes {
         let (use_margins, use_padding) = match self.specific {
-            GenericFragment | IframeFragment(_) | ImageFragment(_) => (true, true),
+            GenericFragment | IframeFragment(_) | ImageFragment(_) | InlineBlockFragment(_) => (true, true),
             TableFragment | TableCellFragment => (false, true),
             TableWrapperFragment => (true, false),
             TableRowFragment => (false, false),
@@ -1082,7 +1098,7 @@ impl Fragment {
                                                                            text_fragment))
             },
             GenericFragment | IframeFragment(..) | TableFragment | TableCellFragment | TableRowFragment |
-            TableWrapperFragment => {
+            TableWrapperFragment | InlineBlockFragment(_) => {
                 // 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))
@@ -1151,6 +1167,11 @@ impl Fragment {
         match self.specific {
             GenericFragment | IframeFragment(_) | TableFragment | TableCellFragment | TableColumnFragment(_) | TableRowFragment |
             TableWrapperFragment => {}
+            InlineBlockFragment(ref mut info) => {
+                let block_flow = info.flow_ref.get_mut().as_block();
+                result.minimum_inline_size = geometry::max(result.minimum_inline_size, block_flow.base.intrinsic_inline_sizes.minimum_inline_size);
+                result.preferred_inline_size = geometry::max(result.preferred_inline_size, block_flow.base.intrinsic_inline_sizes.preferred_inline_size);
+            },
             ImageFragment(ref mut image_fragment_info) => {
                 let image_inline_size = image_fragment_info.image_inline_size();
                 result.minimum_inline_size = geometry::max(result.minimum_inline_size, image_inline_size);
@@ -1191,7 +1212,7 @@ impl Fragment {
     pub fn content_inline_size(&self) -> Au {
         match self.specific {
             GenericFragment | IframeFragment(_) | TableFragment | TableCellFragment | TableRowFragment |
-            TableWrapperFragment => Au(0),
+            TableWrapperFragment | InlineBlockFragment(_) => Au(0),
             ImageFragment(ref image_fragment_info) => {
                 image_fragment_info.computed_inline_size()
             }
@@ -1209,7 +1230,7 @@ impl Fragment {
     pub fn content_block_size(&self, layout_context: &LayoutContext) -> Au {
         match self.specific {
             GenericFragment | IframeFragment(_) | TableFragment | TableCellFragment | TableRowFragment |
-            TableWrapperFragment => Au(0),
+            TableWrapperFragment | InlineBlockFragment(_) => Au(0),
             ImageFragment(ref image_fragment_info) => {
                 image_fragment_info.computed_block_size()
             }
@@ -1246,6 +1267,7 @@ impl Fragment {
             TableRowFragment | TableWrapperFragment => None,
             TableColumnFragment(_) => fail!("Table column fragments do not need to split"),
             UnscannedTextFragment(_) => fail!("Unscanned text fragments should have been scanned by now!"),
+            InlineBlockFragment(_) => fail!("Inline blocks 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();
@@ -1283,7 +1305,7 @@ impl Fragment {
             -> Option<(Option<SplitInfo>, Option<SplitInfo>, Arc<Box<TextRun>> /* TODO(bjz): remove */)> {
         match self.specific {
             GenericFragment | IframeFragment(_) | ImageFragment(_) | TableFragment | TableCellFragment |
-            TableRowFragment | TableWrapperFragment => None,
+            TableRowFragment | TableWrapperFragment | InlineBlockFragment(_) => 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) => {
@@ -1390,7 +1412,7 @@ impl Fragment {
             TableWrapperFragment => return,
             TableColumnFragment(_) => fail!("Table column fragments do not have inline_size"),
             UnscannedTextFragment(_) => fail!("Unscanned text fragments should have been scanned by now!"),
-            ImageFragment(_) | ScannedTextFragment(_) => {}
+            ImageFragment(_) | ScannedTextFragment(_) | InlineBlockFragment(_) => {}
         };
 
         self.compute_border_padding_margins(container_inline_size);
@@ -1400,6 +1422,11 @@ impl Fragment {
         let noncontent_inline_size = self.border_padding.inline_start_end();
 
         match self.specific {
+            InlineBlockFragment(ref mut info) => {
+                let block_flow = info.flow_ref.get_mut().as_block();
+                self.border_box.size.inline = block_flow.base.intrinsic_inline_sizes.preferred_inline_size + noncontent_inline_size;
+                block_flow.base.position.size.inline = self.border_box.size.inline;
+            }
             ScannedTextFragment(_) => {
                 // Scanned text fragments will have already had their content inline-sizes assigned by this
                 // point.
@@ -1441,7 +1468,7 @@ impl Fragment {
             TableWrapperFragment => return,
             TableColumnFragment(_) => fail!("Table column fragments do not have block_size"),
             UnscannedTextFragment(_) => fail!("Unscanned text fragments should have been scanned by now!"),
-            ImageFragment(_) | ScannedTextFragment(_) => {}
+            ImageFragment(_) | ScannedTextFragment(_) | InlineBlockFragment(_) => {}
         }
 
         let style_inline_size = self.style().content_inline_size();
@@ -1480,6 +1507,10 @@ impl Fragment {
                 // during flow construction.
                 self.border_box.size.block = self.border_box.size.block + noncontent_block_size
             }
+            InlineBlockFragment(ref mut info) => {
+                let block_flow = info.flow_ref.get_mut().as_block();
+                self.border_box.size.block = block_flow.base.position.size.block + noncontent_block_size;
+            }
             _ => fail!("should have been handled above"),
         }
     }
@@ -1501,6 +1532,13 @@ impl Fragment {
                 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.get().as_immutable_block();
+                let font_style = text::computed_style_to_font_style(&*self.style);
+                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)
+            }
             _ => {
                 InlineMetrics {
                     block_size_above_baseline: self.border_box.size.block,
@@ -1566,6 +1604,7 @@ impl fmt::Show for Fragment {
                 TableRowFragment => "TableRowFragment",
                 TableWrapperFragment => "TableWrapperFragment",
                 UnscannedTextFragment(_) => "UnscannedTextFragment",
+                InlineBlockFragment(_) => "InlineBlockFragment",
         }));
         try!(write!(f, "bp {}", self.border_padding));
         try!(write!(f, " "));

servo/components/layout/inline.rs

@@ -9,8 +9,8 @@ use context::LayoutContext;
 use floats::{FloatLeft, Floats, PlacementInfo};
 use flow::{BaseFlow, FlowClass, Flow, InlineFlowClass};
 use flow;
-use fragment::{Fragment, ScannedTextFragment, ScannedTextFragmentInfo, SplitInfo};
 use layout_debug;
+use fragment::{Fragment, InlineBlockFragment, ScannedTextFragment, ScannedTextFragmentInfo, SplitInfo};
 use model::IntrinsicISizes;
 use text;
 use wrapper::ThreadSafeLayoutNode;
@@ -20,6 +20,7 @@ use geom::Rect;
 use gfx::display_list::ContentLevel;
 use gfx::font::FontMetrics;
 use gfx::font_context::FontContext;
+use geom::Size2D;
 use gfx::text::glyph::CharIndex;
 use servo_util::geometry::Au;
 use servo_util::geometry;
@@ -760,11 +761,18 @@ impl InlineFlow {
             let rel_offset = fragment.relative_position(&self.base
                                                              .absolute_position_info
                                                              .relative_containing_block_size);
-            drop(fragment.build_display_list(&mut self.base.display_list,
+            let mut accumulator = fragment.build_display_list(&mut self.base.display_list,
                                              layout_context,
                                              self.base.abs_position.add_size(
                                                 &rel_offset.to_physical(self.base.writing_mode)),
-                                             ContentLevel));
+                                             ContentLevel);
+            match fragment.specific {
+                InlineBlockFragment(ref mut block_flow) => {
+                    let block_flow = block_flow.flow_ref.get_mut();
+                    accumulator.push_child(&mut self.base.display_list, block_flow);
+                }
+                _ => {}
+            }
         }
 
         // TODO(#225): Should `inline-block` elements have flows as children of the inline flow or
@@ -949,17 +957,6 @@ impl Flow for InlineFlow {
                 fragment.assign_replaced_inline_size_if_necessary(inline_size);
             }
         }
-
-        assert!(self.base.children.len() == 0,
-                "InlineFlow: should not have children flows in the current layout implementation.");
-
-        // There are no child contexts, so stop here.
-
-        // TODO(Issue #225): once there are 'inline-block' elements, this won't be
-        // true.  In that case, set the InlineBlockFragment's inline-size to the
-        // shrink-to-fit inline-size, perform inline flow, and set the block
-        // flow context's inline-size as the assigned inline-size of the
-        // 'inline-block' fragment that created this flow before recursing.
     }
 
     /// Calculate and set the block-size of this flow. See CSS 2.1 § 10.6.1.
@@ -1118,6 +1115,22 @@ impl Flow for InlineFlow {
         self.base.floats.translate(LogicalSize::new(
             self.base.writing_mode, Au::new(0), -self.base.position.size.block));
     }
+
+    fn compute_absolute_position(&mut self) {
+        for f in self.fragments.fragments.mut_iter() {
+            match f.specific {
+                InlineBlockFragment(ref mut info) => {
+                    let block_flow = info.flow_ref.get_mut().as_block();
+
+                    // FIXME(#2795): Get the real container size
+                    let container_size = Size2D::zero();
+                    block_flow.base.abs_position = self.base.abs_position +
+                                                    f.border_box.start.to_physical(self.base.writing_mode, container_size);
+                }
+                _ => {}
+            }
+        }
+    }
 }
 
 impl fmt::Show for InlineFlow {
@@ -1166,5 +1179,16 @@ impl InlineMetrics {
             ascent: font_metrics.ascent,
         }
     }
+
+    /// Calculates inline metrics from font metrics and line block-size per CSS 2.1 § 10.8.1.
+    #[inline]
+    pub fn from_block_height(font_metrics: &FontMetrics, block_height: Au) -> InlineMetrics {
+        let leading = block_height - (font_metrics.ascent + font_metrics.descent);
+        InlineMetrics {
+            block_size_above_baseline: font_metrics.ascent + leading.scale_by(0.5),
+            depth_below_baseline: font_metrics.descent + leading.scale_by(0.5),
+            ascent: font_metrics.ascent + leading.scale_by(0.5),
+        }
+    }
 }