auto merge of #4394 : pcwalton/servo/clip, r=SimonSapin

Only the recommended, comma-separated syntax is supported.

r? @SimonSapin

components/layout/block.rs

@@ -1774,8 +1774,8 @@ impl Flow for BlockFlow {
         } else {
             self.base.stacking_relative_position
         };
-        let clip_rect = self.fragment.clip_rect_for_children(self.base.clip_rect,
+        let clip_rect = self.fragment.clip_rect_for_children(&self.base.clip_rect,
-                                                             origin_for_children);
+                                                             &origin_for_children);
 
         // Process children.
         let writing_mode = self.base.writing_mode;

components/layout/display_list_builder.rs

@@ -43,9 +43,9 @@ use std::num::FloatMath;
 use style::computed::{AngleOrCorner, LengthOrPercentage, HorizontalDirection, VerticalDirection};
 use style::computed::{Image, LinearGradient};
 use style::computed_values::{background_attachment, background_repeat, border_style, overflow};
-use style::computed_values::{visibility};
+use style::computed_values::{position, visibility};
-use style::{ComputedValues, RGBA};
 use style::style_structs::Border;
+use style::{ComputedValues, RGBA};
 use sync::Arc;
 use url::Url;
 
@@ -167,8 +167,13 @@ pub trait FragmentDisplayListBuilding {
                                             offset: Point2D<Au>,
                                             layout_context: &LayoutContext);
 
-    fn clip_rect_for_children(&self, current_clip_rect: Rect<Au>, flow_origin: Point2D<Au>)
+    fn clip_rect_for_children(&self, current_clip_rect: &Rect<Au>, flow_origin: &Point2D<Au>)
                               -> Rect<Au>;
+
+    /// Calculates the clipping rectangle for a fragment, taking the `clip` property into account
+    /// per CSS 2.1 § 11.1.2.
+    fn calculate_style_specified_clip(&self, parent_clip_rect: &Rect<Au>, origin: &Point2D<Au>)
+                                      -> Rect<Au>;
 }
 
 fn build_border_radius(abs_bounds: &Rect<Au>, border_style: &Border) -> BorderRadii<Au> {
@@ -605,6 +610,24 @@ impl FragmentDisplayListBuilding for Fragment {
         }));
     }
 
+    fn calculate_style_specified_clip(&self, parent_clip_rect: &Rect<Au>, origin: &Point2D<Au>)
+                                      -> Rect<Au> {
+        // Account for `clip` per CSS 2.1 § 11.1.2.
+        let style_clip_rect = match (self.style().get_box().position,
+                                     self.style().get_effects().clip) {
+            (position::absolute, Some(style_clip_rect)) => style_clip_rect,
+            _ => return *parent_clip_rect,
+        };
+
+        // FIXME(pcwalton, #2795): Get the real container size.
+        let border_box = self.border_box.to_physical(self.style.writing_mode, Size2D::zero());
+        let clip_origin = Point2D(border_box.origin.x + style_clip_rect.left,
+                                  border_box.origin.y + style_clip_rect.top);
+        Rect(clip_origin + *origin,
+             Size2D(style_clip_rect.right.unwrap_or(border_box.size.width) - clip_origin.x,
+                    style_clip_rect.bottom.unwrap_or(border_box.size.height) - clip_origin.y))
+    }
+
     fn build_display_list(&mut self,
                           display_list: &mut DisplayList,
                           layout_context: &LayoutContext,
@@ -646,7 +669,11 @@ impl FragmentDisplayListBuilding for Fragment {
             return
         }
 
-        if !absolute_fragment_bounds.intersects(clip_rect) {
+        // Calculate the clip rect. If there's nothing to render at all, don't even construct
+        // display list items.
+        let clip_rect = self.calculate_style_specified_clip(clip_rect,
+                                                            &absolute_fragment_bounds.origin);
+        if !absolute_fragment_bounds.intersects(&clip_rect) {
             return;
         }
 
@@ -666,7 +693,7 @@ impl FragmentDisplayListBuilding for Fragment {
                             layout_context,
                             level,
                             &absolute_fragment_bounds,
-                            clip_rect);
+                            &clip_rect);
                     }
                 }
                 None => {}
@@ -680,7 +707,7 @@ impl FragmentDisplayListBuilding for Fragment {
                         layout_context,
                         level,
                         &absolute_fragment_bounds,
-                        clip_rect);
+                        &clip_rect);
                 }
             }
 
@@ -694,7 +721,7 @@ impl FragmentDisplayListBuilding for Fragment {
                             layout_context,
                             level,
                             &absolute_fragment_bounds,
-                            clip_rect);
+                            &clip_rect);
                     }
                 }
                 None => {}
@@ -708,7 +735,7 @@ impl FragmentDisplayListBuilding for Fragment {
                         layout_context,
                         level,
                         &absolute_fragment_bounds,
-                        clip_rect);
+                        &clip_rect);
                 }
             }
 
@@ -721,12 +748,12 @@ impl FragmentDisplayListBuilding for Fragment {
                             display_list,
                             &absolute_fragment_bounds,
                             level,
-                            clip_rect);
+                            &clip_rect);
                         self.build_display_list_for_outline_if_applicable(
                             &**style,
                             display_list,
                             &absolute_fragment_bounds,
-                            clip_rect);
+                            &clip_rect);
                     }
                 }
                 None => {}
@@ -739,12 +766,12 @@ impl FragmentDisplayListBuilding for Fragment {
                         display_list,
                         &absolute_fragment_bounds,
                         level,
-                        clip_rect);
+                        &clip_rect);
                     self.build_display_list_for_outline_if_applicable(
                         &*self.style,
                         display_list,
                         &absolute_fragment_bounds,
-                        clip_rect);
+                        &clip_rect);
                 }
             }
         }
@@ -781,7 +808,7 @@ impl FragmentDisplayListBuilding for Fragment {
                                                DisplayItemMetadata::new(self.node,
                                                                         self.style(),
                                                                         cursor),
-                                               *clip_rect),
+                                               clip_rect),
                     text_run: text_fragment.run.clone(),
                     range: text_fragment.range,
                     text_color: self.style().get_color().color.to_gfx_color(),
@@ -805,7 +832,7 @@ impl FragmentDisplayListBuilding for Fragment {
                                                   DisplayItemMetadata::new(self.node,
                                                                            style,
                                                                            DefaultCursor),
-                                                  *clip_rect),
+                                                  clip_rect),
                                         color: color.to_gfx_color(),
                                     }))
                             }
@@ -840,7 +867,7 @@ impl FragmentDisplayListBuilding for Fragment {
                                                                    display_list,
                                                                    flow_origin,
                                                                    &**text_fragment,
-                                                                   clip_rect);
+                                                                   &clip_rect);
                 }
             }
             SpecificFragmentInfo::Generic | SpecificFragmentInfo::Iframe(..) | SpecificFragmentInfo::Table | SpecificFragmentInfo::TableCell |
@@ -849,7 +876,7 @@ impl FragmentDisplayListBuilding for Fragment {
                 if opts::get().show_debug_fragment_borders {
                     self.build_debug_borders_around_fragment(display_list,
                                                              flow_origin,
-                                                             clip_rect);
+                                                             &clip_rect);
                 }
             }
             SpecificFragmentInfo::Image(ref mut image_fragment) => {
@@ -864,7 +891,7 @@ impl FragmentDisplayListBuilding for Fragment {
                                                        DisplayItemMetadata::new(self.node,
                                                                                 &*self.style,
                                                                                 DefaultCursor),
-                                                       *clip_rect),
+                                                       clip_rect),
                             image: image.clone(),
                             stretch_size: absolute_content_box.size,
                         }));
@@ -880,9 +907,7 @@ impl FragmentDisplayListBuilding for Fragment {
         }
 
         if opts::get().show_debug_fragment_borders {
-           self.build_debug_borders_around_fragment(display_list,
+           self.build_debug_borders_around_fragment(display_list, flow_origin, &clip_rect)
-                                                    flow_origin,
-                                                    clip_rect)
         }
 
         // If this is an iframe, then send its position and size up to the constellation.
@@ -926,14 +951,17 @@ impl FragmentDisplayListBuilding for Fragment {
                                iframe_rect));
     }
 
-    fn clip_rect_for_children(&self, current_clip_rect: Rect<Au>, flow_origin: Point2D<Au>)
+    fn clip_rect_for_children(&self, current_clip_rect: &Rect<Au>, origin: &Point2D<Au>)
                               -> Rect<Au> {
         // Don't clip if we're text.
         match self.specific {
-            SpecificFragmentInfo::ScannedText(_) => return current_clip_rect,
+            SpecificFragmentInfo::ScannedText(_) => return *current_clip_rect,
             _ => {}
         }
 
+        // Account for style-specified `clip`.
+        let current_clip_rect = self.calculate_style_specified_clip(current_clip_rect, origin);
+
         // Only clip if `overflow` tells us to.
         match self.style.get_box().overflow {
             overflow::hidden | overflow::auto | overflow::scroll => {}
@@ -944,7 +972,8 @@ impl FragmentDisplayListBuilding for Fragment {
         //
         // 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,
+        current_clip_rect.intersection(&Rect(Point2D(physical_rect.origin.x + origin.x,
+                                                     physical_rect.origin.y + origin.y),
                                              physical_rect.size)).unwrap_or(ZERO_RECT)
     }
 }

components/layout/inline.rs

@@ -1215,8 +1215,8 @@ impl Flow for InlineFlow {
                 _ => continue,
             };
 
-            let clip_rect = fragment.clip_rect_for_children(self.base.clip_rect,
+            let clip_rect = fragment.clip_rect_for_children(&self.base.clip_rect,
-                                                            stacking_relative_position);
+                                                            &stacking_relative_position);
 
             match fragment.specific {
                 SpecificFragmentInfo::InlineBlock(ref mut info) => {

components/servo/Cargo.lock

@@ -247,7 +247,7 @@ source = "git+https://github.com/alexcrichton/gcc-rs#903e8f8a2e3766ad3d514404d45
 [[package]]
 name = "geom"
 version = "0.1.0"
-source = "git+https://github.com/servo/rust-geom#5e52790076fc238a395d1777c4280fa46a1555fa"
+source = "git+https://github.com/servo/rust-geom#da6b4a36a5549cf78bf702f0b9387b5c8cf61498"
 
 [[package]]
 name = "gfx"

components/style/properties/mod.rs.mako

@@ -1861,6 +1861,84 @@ pub mod longhands {
             })
         }
     </%self:longhand>
+
+    <%self:single_component_value name="clip">
+        // NB: `top` and `left` are 0 if `auto` per CSS 2.1 11.1.2.
+
+        pub mod computed_value {
+            use super::super::Au;
+
+            #[deriving(Clone, PartialEq, Show)]
+            pub struct ClipRect {
+                pub top: Au,
+                pub right: Option<Au>,
+                pub bottom: Option<Au>,
+                pub left: Au,
+            }
+
+            pub type T = Option<ClipRect>;
+        }
+
+        #[deriving(Clone, Show)]
+        pub struct SpecifiedClipRect {
+            pub top: specified::Length,
+            pub right: Option<specified::Length>,
+            pub bottom: Option<specified::Length>,
+            pub left: specified::Length,
+        }
+
+        pub type SpecifiedValue = Option<SpecifiedClipRect>;
+
+        #[inline]
+        pub fn get_initial_value() -> computed_value::T {
+            None
+        }
+
+        pub fn to_computed_value(value: SpecifiedValue, context: &computed::Context)
+                                 -> computed_value::T {
+            value.map(|value| computed_value::ClipRect {
+                top: computed::compute_Au(value.top, context),
+                right: value.right.map(|right| computed::compute_Au(right, context)),
+                bottom: value.bottom.map(|bottom| computed::compute_Au(bottom, context)),
+                left: computed::compute_Au(value.left, context),
+            })
+        }
+
+        pub fn from_component_value(input: &ComponentValue, _: &Url) -> Result<SpecifiedValue,()> {
+            match *input {
+                Function(ref name, ref args) if name.as_slice().eq_ignore_ascii_case("rect") => {
+                    let sides = try!(parse_slice_comma_separated(args.as_slice(), |parser| {
+                        match parser.next() {
+                            Some(&Ident(ref ident)) if ident.eq_ignore_ascii_case("auto") => {
+                                Ok(None)
+                            }
+                            Some(arg) => {
+                                match specified::Length::parse(arg) {
+                                    Err(_) => {
+                                        parser.push_back(arg);
+                                        Err(())
+                                    }
+                                    Ok(value) => Ok(Some(value)),
+                                }
+                            }
+                            None => Err(()),
+                        }
+                    }));
+                    if sides.len() != 4 {
+                        return Err(())
+                    }
+                    Ok(Some(SpecifiedClipRect {
+                        top: sides[0].unwrap_or(specified::Length::Au(Au(0))),
+                        right: sides[1],
+                        bottom: sides[2],
+                        left: sides[3].unwrap_or(specified::Length::Au(Au(0))),
+                    }))
+                }
+                Ident(ref ident) if ident.as_slice().eq_ignore_ascii_case("auto") => Ok(None),
+                _ => Err(())
+            }
+        }
+    </%self:single_component_value>
 }
 
 

components/util/geometry.rs

@@ -333,3 +333,4 @@ pub fn f32_rect_to_au_rect(rect: Rect<f32>) -> Rect<Au> {
     Rect(Point2D(Au::from_frac32_px(rect.origin.x), Au::from_frac32_px(rect.origin.y)),
          Size2D(Au::from_frac32_px(rect.size.width), Au::from_frac32_px(rect.size.height)))
 }
+

ports/cef/Cargo.lock

@@ -243,7 +243,7 @@ source = "git+https://github.com/alexcrichton/gcc-rs#903e8f8a2e3766ad3d514404d45
 [[package]]
 name = "geom"
 version = "0.1.0"
-source = "git+https://github.com/servo/rust-geom#5e52790076fc238a395d1777c4280fa46a1555fa"
+source = "git+https://github.com/servo/rust-geom#da6b4a36a5549cf78bf702f0b9387b5c8cf61498"
 
 [[package]]
 name = "gfx"

ports/gonk/Cargo.lock

@@ -207,7 +207,7 @@ source = "git+https://github.com/alexcrichton/gcc-rs#d35c34c871dd75f97fadf04cb0e
 [[package]]
 name = "geom"
 version = "0.1.0"
-source = "git+https://github.com/servo/rust-geom#5e52790076fc238a395d1777c4280fa46a1555fa"
+source = "git+https://github.com/servo/rust-geom#da6b4a36a5549cf78bf702f0b9387b5c8cf61498"
 
 [[package]]
 name = "gfx"

tests/ref/basic.list

@@ -218,3 +218,4 @@ fragment=top != ../html/acid2.html acid2_ref.html
 == empty_cells_a.html empty_cells_ref.html
 == table_caption_top_a.html table_caption_top_ref.html
 == table_caption_bottom_a.html table_caption_bottom_ref.html
+== clip_a.html clip_ref.html

tests/ref/clip_a.html

@@ -0,0 +1,52 @@
+<!DOCTYPE html>
+<html>
+<head>
+<!-- Tests that various `clip` values per CSS 2.1 work. -->
+<style>
+section {
+    position: absolute;
+    padding: 32px;
+    width: 64px;
+    height: 64px;
+    background: green;
+    border: solid 32px red;
+}
+section:before {
+    content: "";
+    display: block;
+    padding: 0;
+    width: 64px;
+    height: 64px;
+    background: blue;
+}
+#a {
+    top: 0;
+    left: 0;
+    clip: rect(auto, auto, auto, auto);
+}
+#b {
+    top: 192px;
+    left: 0;
+    clip: rect(32px, auto, auto, 128px);
+}
+#c {
+    top: 0;
+    left: 192px;
+    clip: rect(32px, 128px, 64px, 0);
+}
+#d {
+    top: 192px;
+    left: 192px;
+    clip: rect(64px, 0, 64px, 0);
+}
+</style>
+</head>
+<body>
+<section id=a></section>
+<section id=b></section>
+<section id=c></section>
+<section id=d></section>
+</body>
+</html>
+
+

tests/ref/clip_ref.html

@@ -0,0 +1,70 @@
+<!DOCTYPE html>
+<html>
+<head>
+<!-- Tests that various `clip` values per CSS 2.1 work. -->
+<style>
+section {
+    position: absolute;
+}
+#a {
+    top: 0;
+    left: 0;
+    width: 192px;
+    height: 192px;
+    background: red;
+}
+#b {
+    top: 32px;
+    left: 32px;
+    width: 128px;
+    height: 128px;
+    background: green;
+}
+#c {
+    top: 64px;
+    left: 64px;
+    width: 64px;
+    height: 64px;
+    background: blue;
+}
+#d {
+    top: 32px;
+    left: 192px;
+    width: 32px;
+    height: 32px;
+    background: red;
+}
+#e {
+    top: 32px;
+    left: 224px;
+    width: 96px;
+    height: 32px;
+    background: green;
+}
+#f {
+    top: 224px;
+    left: 128px;
+    width: 64px;
+    height: 160px;
+    background: red;
+}
+#g {
+    top: 224px;
+    left: 128px;
+    width: 32px;
+    height: 128px;
+    background: green;
+}
+</style>
+</head>
+<body>
+<section id=a></section>
+<section id=b></section>
+<section id=c></section>
+<section id=d></section>
+<section id=e></section>
+<section id=f></section>
+<section id=g></section>
+</body>
+</html>
+