[Cocoa] Small canvases, which aren't supposed to get compositing laye…

…rs, get compositing layers if they have a 3D-but-could-be-2D transform https://bugs.webkit.org/show_bug.cgi?id=259297 rdar://112439265 Reviewed by Simon Fraser. We already have existing code which will avoid compositing small canvases. However, if the small canvas has a 3D-but-could-be-2D transform, we'll composite it regardless. This patch extends the current logic to not composite small canvases in this case. This patch causes a 41% - 48% progression on the Images subtest in MotionMark. Layers have cost, y'all. * LayoutTests/compositing/canvas/accelerated-small-canvas-compositing-expected.txt * LayoutTests/compositing/canvas/accelerated-small-canvas-compositing.html * Source/WebCore/rendering/RenderLayerCompositor.cpp: (WebCore::RenderLayerCompositor::requiresCompositingForTransform const): This patch doesn't modify m_compositingPolicy, because that's global for the whole RenderLayerCompositor. We only want to change the policy in this specific case. Canonical link: https://commits.webkit.org/266135@main
WebKit · Jul 18, 2023 · 3dfb58b · 3dfb58b
1 parent 0aa032e
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diff --git a/LayoutTests/compositing/canvas/accelerated-small-canvas-compositing-expected.txt b/LayoutTests/compositing/canvas/accelerated-small-canvas-compositing-expected.txt
@@ -0,0 +1,19 @@
+Tests whether an accelerated canvas creates a compositing layer.
+
+ (GraphicsLayer
+  (anchor 0.00 0.00)
+  (bounds 800.00 600.00)
+  (children 1
+    (GraphicsLayer
+      (bounds 800.00 600.00)
+      (contentsOpaque 1)
+      (children 1
+        (GraphicsLayer
+          (position 8.00 68.00)
+          (bounds 15.00 15.00)
+        )
+      )
+    )
+  )
+)
+
diff --git a/LayoutTests/compositing/canvas/accelerated-small-canvas-compositing.html b/LayoutTests/compositing/canvas/accelerated-small-canvas-compositing.html
@@ -0,0 +1,40 @@
+<!DOCTYPE html><html>
+<head>
+<style>
+canvas {
+    transform: translateZ(0px);
+}
+div {
+    will-change: transform;
+    width: 15px;
+    height: 15px;
+}
+</style>
+<script>
+    if (window.testRunner) {
+      testRunner.dumpAsText();
+      testRunner.waitUntilDone();
+    }
+
+    function doTest() {
+        var c = document.getElementById('cvs_img2');
+        var ctx = c.getContext('2d');
+        ctx.fillStyle = 'green';
+        ctx.fillRect(0,0,c.width, c.height);
+
+        if (window.testRunner) {
+            document.getElementById('layers').innerText = window.internals.layerTreeAsText(document);
+            testRunner.notifyDone();
+        }
+    }
+
+    window.addEventListener('load', doTest, false);
+</script>
+</head>
+<body>
+<p>Tests whether an accelerated canvas creates a compositing layer.</p>
+<canvas id="cvs_img2" width="10" height="10"></canvas>
+<div></div>
+<pre id="layers">Layer tree goes here in DRT</pre>
+</body>
+</html>
diff --git a/...utTests/platform/gtk/compositing/canvas/accelerated-small-canvas-compositing-expected.txt b/...utTests/platform/gtk/compositing/canvas/accelerated-small-canvas-compositing-expected.txt
@@ -0,0 +1,24 @@
+Tests whether an accelerated canvas creates a compositing layer.
+
+ (GraphicsLayer
+  (anchor 0.00 0.00)
+  (bounds 800.00 600.00)
+  (children 1
+    (GraphicsLayer
+      (bounds 800.00 600.00)
+      (contentsOpaque 1)
+      (children 2
+        (GraphicsLayer
+          (position 8.00 54.00)
+          (bounds 10.00 10.00)
+          (drawsContent 1)
+        )
+        (GraphicsLayer
+          (position 8.00 68.00)
+          (bounds 15.00 15.00)
+        )
+      )
+    )
+  )
+)
+
diff --git a/...utTests/platform/ios/compositing/canvas/accelerated-small-canvas-compositing-expected.txt b/...utTests/platform/ios/compositing/canvas/accelerated-small-canvas-compositing-expected.txt
@@ -0,0 +1,19 @@
+Tests whether an accelerated canvas creates a compositing layer.
+
+ (GraphicsLayer
+  (anchor 0.00 0.00)
+  (bounds 800.00 600.00)
+  (children 1
+    (GraphicsLayer
+      (bounds 800.00 600.00)
+      (contentsOpaque 1)
+      (children 1
+        (GraphicsLayer
+          (position 8.00 72.00)
+          (bounds 15.00 15.00)
+        )
+      )
+    )
+  )
+)
+
diff --git a/Source/WebCore/rendering/RenderLayerCompositor.cpp b/Source/WebCore/rendering/RenderLayerCompositor.cpp
@@ -3246,8 +3246,18 @@ bool RenderLayerCompositor::requiresCompositingForTransform(RenderLayerModelObje
     // but the renderer may be an inline that doesn't suppport them.
     if (!renderer.isTransformed())
         return false;
+
+    auto compositingPolicy = m_compositingPolicy;
+#if !USE(COMPOSITING_FOR_SMALL_CANVASES)
+    if (is<HTMLCanvasElement>(renderer.element())) {
+        auto* canvas = downcast<HTMLCanvasElement>(renderer.element());
+        auto canvasArea = canvas->size().area<RecordOverflow>();
+        if (!canvasArea.hasOverflowed() && canvasArea < canvasAreaThresholdRequiringCompositing)
+            compositingPolicy = CompositingPolicy::Conservative;
+    }
+#endif
 
-    switch (m_compositingPolicy) {
+    switch (compositingPolicy) {
     case CompositingPolicy::Normal:
         return styleHas3DTransformOperation(renderer.style());
     case CompositingPolicy::Conservative: