Bug 1573649 - Implement feOffset SVG filter primitive in WebRender r=nical

Differential Revision: https://phabricator.services.mozilla.com/D41840

--HG--
extra : moz-landing-system : lando

gfx/wr/webrender/src/picture.rs

@@ -1964,6 +1964,10 @@ impl PictureCompositeMode {
                             primitive.input.to_index(cur_index).map(|index| output_rects[index]).unwrap_or(picture_rect),
                         FilterPrimitiveKind::ComponentTransfer(ref primitive) =>
                             primitive.input.to_index(cur_index).map(|index| output_rects[index]).unwrap_or(picture_rect),
+                        FilterPrimitiveKind::Offset(ref primitive) => {
+                            let input_rect = primitive.input.to_index(cur_index).map(|index| output_rects[index]).unwrap_or(picture_rect);
+                            input_rect.translate(primitive.offset * Scale::new(1.0))
+                        },
 
                         FilterPrimitiveKind::Flood(..) => picture_rect,
                     };

gfx/wr/webrender/src/prim_store/picture.rs

@@ -31,6 +31,7 @@ pub enum FilterPrimitiveKey {
     ColorMatrix(ColorSpace, [Au; 20], FilterPrimitiveInput),
     DropShadow(ColorSpace, (VectorKey, Au, ColorU), FilterPrimitiveInput),
     ComponentTransfer(ColorSpace, FilterPrimitiveInput, Vec<SFilterData>),
+    Offset(ColorSpace, FilterPrimitiveInput, VectorKey),
 }
 
 /// Represents a hashable description of how a picture primitive
@@ -175,6 +176,8 @@ impl From<Option<PictureCompositeMode>> for PictureCompositeKey {
                         }
                         FilterPrimitiveKind::ComponentTransfer(component_transfer) =>
                             FilterPrimitiveKey::ComponentTransfer(primitive.color_space, component_transfer.input, filter_data.clone()),
+                        FilterPrimitiveKind::Offset(info) =>
+                            FilterPrimitiveKey::Offset(primitive.color_space, info.input, info.offset.into()),
                     }
                 }).collect())
             }

gfx/wr/webrender/src/render_task.rs

@@ -1476,6 +1476,26 @@ impl RenderTask {
                         render_tasks.add(task)
                     }
                 }
+                FilterPrimitiveKind::Offset(ref info) => {
+                    let input_task_id = get_task_input(
+                        &info.input,
+                        filter_primitives,
+                        render_tasks,
+                        cur_index,
+                        &outputs,
+                        original_task_id,
+                        primitive.color_space
+                    );
+
+                    let offset = info.offset * LayoutToWorldScale::new(1.0) * device_pixel_scale;
+                    let offset_task = RenderTask::new_svg_filter_primitive(
+                        vec![input_task_id],
+                        content_size,
+                        uv_rect_kind,
+                        SvgFilterInfo::Offset(offset),
+                    );
+                    render_tasks.add(offset_task)
+                }
             };
             outputs.push(render_task_id);
         }

gfx/wr/webrender_api/src/display_item.rs

@@ -837,6 +837,13 @@ pub struct IdentityPrimitive {
     pub input: FilterPrimitiveInput,
 }
 
+#[repr(C)]
+#[derive(Clone, Copy, Debug, Default, Deserialize, PartialEq, Serialize, PeekPoke)]
+pub struct OffsetPrimitive {
+    pub input: FilterPrimitiveInput,
+    pub offset: LayoutVector2D,
+}
+
 /// See: https://github.com/eqrion/cbindgen/issues/9
 /// cbindgen:derive-eq=false
 #[repr(C)]
@@ -852,6 +859,7 @@ pub enum FilterPrimitiveKind {
     ColorMatrix(ColorMatrixPrimitive),
     DropShadow(DropShadowPrimitive),
     ComponentTransfer(ComponentTransferPrimitive),
+    Offset(OffsetPrimitive),
 }
 
 impl Default for FilterPrimitiveKind {
@@ -872,6 +880,7 @@ impl FilterPrimitiveKind {
             FilterPrimitiveKind::Identity(..) |
             FilterPrimitiveKind::Blend(..) |
             FilterPrimitiveKind::ColorMatrix(..) |
+            FilterPrimitiveKind::Offset(..) |
             // Component transfer's filter data is sanitized separately.
             FilterPrimitiveKind::ComponentTransfer(..) => {}
         }

gfx/wr/wrench/reftests/filters/reftest.list

@@ -58,3 +58,4 @@ platform(linux,mac) == svg-filter-drop-shadow-on-viewport-edge.yaml svg-filter-d
 platform(linux,mac) == svg-filter-drop-shadow-perspective.yaml svg-filter-drop-shadow-perspective.png
 == backdrop-filter-basic.yaml backdrop-filter-basic-ref.yaml
 platform(linux,mac) == backdrop-filter-perspective.yaml backdrop-filter-perspective.png
+platform(linux,max) == svg-filter-offset.yaml svg-filter-offset-ref.yaml

gfx/wr/wrench/reftests/filters/svg-filter-offset-ref.yaml

@@ -0,0 +1,11 @@
+# Tests the SVG offset filter primitive
+# An offset filter should have the same effect as changing the origin of the rectangle.
+---
+root:
+  items:
+    - type: stacking-context
+      bounds: 0 0 0 0
+      items:
+      - type: rect
+        bounds: 20 20 100 100
+        color: red

gfx/wr/wrench/reftests/filters/svg-filter-offset.yaml

@@ -0,0 +1,15 @@
+# Tests the SVG offset filter primitive
+# An offset filter should have the same effect as changing the origin of the rectangle.
+---
+root:
+  items:
+    - type: stacking-context
+      bounds: 0 0 0 0
+      filter-primitives:
+      - type: offset
+        offset: 10 10
+        in: original
+      items:
+      - type: rect
+        bounds: 10 10 100 100
+        color: red

gfx/wr/wrench/src/yaml_frame_writer.rs

@@ -399,6 +399,11 @@ fn write_filter_primitives(
                 yaml_node(&mut table, "type", Yaml::String("component-transfer".into()));
                 filter_input_node(&mut table, "in", component_transfer_primitive.input);
             }
+            FilterPrimitiveKind::Offset(info) => {
+                yaml_node(&mut table, "type", Yaml::String("offset".into()));
+                filter_input_node(&mut table, "in", info.input);
+                vector_node(&mut table, "offset", &info.offset);
+            }
         }
         enum_node(&mut table, "color-space", filter_primitive.color_space);
         filter_primitives.push(Yaml::Hash(table));

gfx/wr/wrench/src/yaml_helper.rs

@@ -769,6 +769,12 @@ impl YamlHelper for Yaml {
                         input: self["in"].as_filter_input().unwrap(),
                     })
                 }
+                "offset" => {
+                    FilterPrimitiveKind::Offset(OffsetPrimitive {
+                        input: self["in"].as_filter_input().unwrap(),
+                        offset: self["offset"].as_vector().unwrap(),
+                    })
+                }
                 _ => return None,
             };