This ensures that the viewport anchor layer will be updated when upda…

…ting compositing layers upon style change https://bugs.webkit.org/show_bug.cgi?id=246890 rdar://99568474 Reviewed by Simon Fraser. * LayoutTests/compositing/scrolling/fixed-style-with-rotation.html: Added. * LayoutTests/compositing/scrolling/sticky-style-with-rotation.html: Added. * Source/WebCore/rendering/RenderLayerCompositor.cpp: (WebCore::RenderLayerCompositor::layerStyleChanged): Canonical link: https://commits.webkit.org/256025@main
WebKit · Oct 26, 2022 · 67c0ccb · 67c0ccb
1 parent c4f1f9c
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diff --git a/LayoutTests/compositing/scrolling/fixed-style-with-rotation-expected.txt b/LayoutTests/compositing/scrolling/fixed-style-with-rotation-expected.txt
@@ -0,0 +1 @@
+The HTML page loads as expected
diff --git a/LayoutTests/compositing/scrolling/fixed-style-with-rotation.html b/LayoutTests/compositing/scrolling/fixed-style-with-rotation.html
@@ -0,0 +1,20 @@
+<!DOCTYPE html>
+<style>
+    body {
+        rotate: y 1turn;
+    }
+</style>
+<body>
+    <p>The HTML page loads as expected</p>
+</body>
+<script>
+    if (window.testRunner)
+        testRunner.dumpAsText();
+
+    onload = () => {
+        document.body.offsetTop;
+        document.body.style.position = 'fixed';
+        scrollBy(0, 0);
+    };
+</script>
+
diff --git a/LayoutTests/compositing/scrolling/sticky-style-with-rotation-expected.txt b/LayoutTests/compositing/scrolling/sticky-style-with-rotation-expected.txt
@@ -0,0 +1 @@
+The HTML page loads as expected
diff --git a/LayoutTests/compositing/scrolling/sticky-style-with-rotation.html b/LayoutTests/compositing/scrolling/sticky-style-with-rotation.html
@@ -0,0 +1,20 @@
+<!DOCTYPE html>
+<style>
+    body {
+        rotate: y 1turn;
+    }
+</style>
+<body>
+    <p>The HTML page loads as expected</p>
+</body>
+<script>
+    if (window.testRunner)
+        testRunner.dumpAsText();
+
+    onload = () => {
+        document.body.offsetTop;
+        document.body.style.position = 'sticky';
+        scrollBy(0, 0);
+    };
+</script>
+
diff --git a/Source/WebCore/rendering/RenderLayerCompositor.cpp b/Source/WebCore/rendering/RenderLayerCompositor.cpp
@@ -1727,6 +1727,17 @@ void RenderLayerCompositor::layerStyleChanged(StyleDifference diff, RenderLayer&
                 }
             }
 
+            // This ensures that the viewport anchor layer will be updated when updating compositing layers upon style change
+            auto styleChangeAffectsAnchorLayer = [](const RenderStyle* oldStyle, const RenderStyle& newStyle) {
+                if (!oldStyle)
+                    return false;
+
+                return oldStyle->hasViewportConstrainedPosition() != newStyle.hasViewportConstrainedPosition();
+            };
+
+            if (styleChangeAffectsAnchorLayer(oldStyle, newStyle))
+                layer.setNeedsCompositingConfigurationUpdate();
+
             // These properties trigger compositing if some descendant is composited.
             if (oldStyle && styleChangeMayAffectIndirectCompositingReasons(*oldStyle, newStyle))
                 layer.setNeedsPostLayoutCompositingUpdate();