Merge r269588 - [TextureMapper] The top and left sides of drop-shadow…

… are clipped https://bugs.webkit.org/show_bug.cgi?id=218647 Reviewed by Don Olmstead. Source/WebCore: TextureMapperLayer::computeOverlapRegions incorrectly calculated the local bounding rect for top and left of outsets. The drop-shadow was incorrectly blended with the content. Test: compositing/filters/drop-shadow.html * platform/graphics/texmap/TextureMapperLayer.cpp: (WebCore::TextureMapperLayer::computeOverlapRegions): Stopped using std::max for the left and top of outsets. Stopped taking the unite with unfilteredTargetRect because outsets are always positive. * platform/graphics/texmap/TextureMapperShaderProgram.cpp: Fixed sourceOver(). LayoutTests: * compositing/filters/drop-shadow-expected.html: Added. * compositing/filters/drop-shadow.html: Added.
WebKit · Nov 20, 2020 · 866dfa8 · 866dfa8
1 parent 66a605f
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diff --git a/LayoutTests/ChangeLog b/LayoutTests/ChangeLog
@@ -1,3 +1,13 @@
+2020-11-09  Fujii Hironori  <Hironori.Fujii@sony.com>
+
+        [TextureMapper] The top and left sides of drop-shadow are clipped
+        https://bugs.webkit.org/show_bug.cgi?id=218647
+
+        Reviewed by Don Olmstead.
+
+        * compositing/filters/drop-shadow-expected.html: Added.
+        * compositing/filters/drop-shadow.html: Added.
+
 2020-11-08  Fujii Hironori  <Hironori.Fujii@sony.com>
 
         TextureMapperLayer::computeOverlapRegions: Accumulate nested replica transform matrices recursively

diff --git a/LayoutTests/compositing/filters/drop-shadow-expected.html b/LayoutTests/compositing/filters/drop-shadow-expected.html
@@ -0,0 +1,40 @@
+<!DOCTYPE html>
+<html>
+    <head>
+        <style>
+            #x {
+                transform: translate(100px, 100px);
+            }
+            div div {
+                position: absolute;
+                width: 100px;
+                height: 100px;
+                background: green;
+            }
+            .a {
+                transform: translate(-60px, -60px);
+                filter: drop-shadow(-20px -20px 0px blue);
+            }
+            .b {
+                transform: translate(-60px, 60px);
+                filter: drop-shadow(-20px 20px 0px blue);
+            }
+            .c {
+                transform: translate(60px, -60px);
+                filter: drop-shadow(20px -20px 0px blue);
+            }
+            .d {
+                transform: translate(60px, 60px);
+                filter: drop-shadow(20px 20px 0px blue);
+            }
+        </style>
+    </head>
+    <body>
+        <div id=x>
+            <div class=a></div>
+            <div class=b></div>
+            <div class=c></div>
+            <div class=d></div>
+        </div>
+    </body>
+</html>
diff --git a/LayoutTests/compositing/filters/drop-shadow.html b/LayoutTests/compositing/filters/drop-shadow.html
@@ -0,0 +1,41 @@
+<!DOCTYPE html>
+<html>
+    <head>
+        <style>
+            #x {
+                transform: translate(100px, 100px);
+            }
+            div div {
+                position: absolute;
+                width: 100px;
+                height: 100px;
+                background: green;
+                will-change: transform;
+            }
+            .a {
+                transform: translate(-60px, -60px);
+                filter: drop-shadow(-20px -20px 0px blue);
+            }
+            .b {
+                transform: translate(-60px, 60px);
+                filter: drop-shadow(-20px 20px 0px blue);
+            }
+            .c {
+                transform: translate(60px, -60px);
+                filter: drop-shadow(20px -20px 0px blue);
+            }
+            .d {
+                transform: translate(60px, 60px);
+                filter: drop-shadow(20px 20px 0px blue);
+            }
+        </style>
+    </head>
+    <body>
+        <div id=x>
+            <div class=a></div>
+            <div class=b></div>
+            <div class=c></div>
+            <div class=d></div>
+        </div>
+    </body>
+</html>
diff --git a/Source/WebCore/ChangeLog b/Source/WebCore/ChangeLog
@@ -1,3 +1,25 @@
+2020-11-09  Fujii Hironori  <Hironori.Fujii@sony.com>
+
+        [TextureMapper] The top and left sides of drop-shadow are clipped
+        https://bugs.webkit.org/show_bug.cgi?id=218647
+
+        Reviewed by Don Olmstead.
+
+        TextureMapperLayer::computeOverlapRegions incorrectly calculated
+        the local bounding rect for top and left of outsets.
+
+        The drop-shadow was incorrectly blended with the content.
+
+        Test: compositing/filters/drop-shadow.html
+
+        * platform/graphics/texmap/TextureMapperLayer.cpp:
+        (WebCore::TextureMapperLayer::computeOverlapRegions): Stopped
+        using std::max for the left and top of outsets. Stopped taking the
+        unite with unfilteredTargetRect because outsets are always
+        positive.
+        * platform/graphics/texmap/TextureMapperShaderProgram.cpp:
+        Fixed sourceOver().
+
 2020-11-08  Fujii Hironori  <Hironori.Fujii@sony.com>
 
         TextureMapperLayer::computeOverlapRegions: Accumulate nested replica transform matrices recursively

diff --git a/Source/WebCore/platform/graphics/texmap/TextureMapperLayer.cpp b/Source/WebCore/platform/graphics/texmap/TextureMapperLayer.cpp
@@ -332,10 +332,8 @@ void TextureMapperLayer::computeOverlapRegions(ComputeOverlapRegionData& data, c
 
     if (m_currentFilters.hasOutsets()) {
         auto outsets = m_currentFilters.outsets();
-        IntRect unfilteredTargetRect(localBoundingRect);
-        localBoundingRect.move(std::max(0, -outsets.left()), std::max(0, -outsets.top()));
+        localBoundingRect.move(-outsets.left(), -outsets.top());
         localBoundingRect.expand(outsets.left() + outsets.right(), outsets.top() + outsets.bottom());
-        localBoundingRect.unite(unfilteredTargetRect);
     }
 
     TransformationMatrix transform(accumulatedReplicaTransform);

diff --git a/Source/WebCore/platform/graphics/texmap/TextureMapperShaderProgram.cpp b/Source/WebCore/platform/graphics/texmap/TextureMapperShaderProgram.cpp
@@ -393,7 +393,7 @@ static const char* fragmentTemplateCommon =
             color *= total;
         }
 
-        vec4 sourceOver(vec4 src, vec4 dst) { return src + dst * (1. - dst.a); }
+        vec4 sourceOver(vec4 src, vec4 dst) { return src + dst * (1. - src.a); }
 
         void applyContentTexture(inout vec4 color, vec2 texCoord)
         {