Backed out changeset 41acfa78dae4 (bug 1559861) for Wrench failure in transforms/raster-root-scaling.yaml

gfx/wr/webrender/src/picture.rs

@@ -5941,26 +5941,16 @@ impl PicturePrimitive {
                 false
             };
 
-            let surface_to_parent_transform = frame_context.spatial_tree
-                .get_relative_transform(surface_spatial_node_index, parent_raster_node_index);
-
             // Check if there is perspective or if an SVG filter is applied, and thus whether a new
             // rasterization root should be established.
-            let establishes_raster_root = has_svg_filter || surface_to_parent_transform.is_perspective();
+            let establishes_raster_root = has_svg_filter || frame_context.spatial_tree
+                .get_relative_transform(surface_spatial_node_index, parent_raster_node_index)
+                .is_perspective();
 
-            let (raster_spatial_node_index, device_pixel_scale) = if establishes_raster_root {
-                // If a raster root is established, this surface should be scaled based on the scale factors of the surface raster to parent raster transform.
-                // This scaling helps ensure that the content in this surface does not become blurry or pixelated when composited in the parent surface.
-                let scale_factors = surface_to_parent_transform.scale_factors();
-
-                // Pick the largest scale factor of the transform for the scaling factor.
-                // Currently, we ensure that the scaling factor is >= 1.0 as a smaller scale factor can result in blurry output.
-                let scaling_factor = scale_factors.0.max(scale_factors.1).max(1.0);
-
-                let device_pixel_scale = frame_context.global_device_pixel_scale * Scale::new(scaling_factor);
-                (surface_spatial_node_index, device_pixel_scale)
+            let raster_spatial_node_index = if establishes_raster_root {
+                surface_spatial_node_index
             } else {
-                (parent_raster_node_index, frame_context.global_device_pixel_scale)
+                parent_raster_node_index
             };
 
             let scale_factors = frame_context
@@ -6012,7 +6002,7 @@ impl PicturePrimitive {
                 inflation_factor,
                 frame_context.global_screen_world_rect,
                 &frame_context.spatial_tree,
-                device_pixel_scale,
+                frame_context.global_device_pixel_scale,
                 scale_factors,
             );
 

gfx/wr/wrench/reftests/transforms/raster-root-scaling-ref.yaml

@@ -1,10 +0,0 @@
-
-# Tests that surfaces created by raster roots are scaled based on the surface to parent transform.
----
-root:
-  items:
-    - type: stacking-context
-      bounds: [0, 0, 0, 0]
-      items:
-        - image: checkerboard(2, 16, 16)
-          bounds: [0, 0, 260, 260]

gfx/wr/wrench/reftests/transforms/raster-root-scaling.yaml

@@ -1,16 +0,0 @@
-# Tests that surfaces created by raster roots are scaled based on the surface to parent transform.
----
-root:
-  items:
-    - type: stacking-context
-      bounds: [0, 0, 0, 0]
-      # Force WebRender to form a raster root
-      transform: perspective(1000)
-      items:
-      - type: stacking-context
-        bounds: [0, 0, 0, 0]
-        transform-style: preserve-3d
-        transform: scale(10,10)
-        items:
-          - image: checkerboard(2, 16, 16)
-            bounds: [0, 0, 26, 26]

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

@@ -48,4 +48,3 @@ skip_on(android) fuzzy-range(<=3,*3077,<=10,*133,<=93,*490) == raster_root_A_819
 skip_on(android) fuzzy(60,917) == raster_root_B_8192.yaml raster_root_B_ref.yaml
 # Make sure we don't panic
 != raster-root-large-mask.yaml blank.yaml
-== raster-root-scaling.yaml raster-root-scaling-ref.yaml