REGRESSION(275801@main): In some cases, InteractionRegion layers accu…

…mulate in the layer tree https://bugs.webkit.org/show_bug.cgi?id=271195 <rdar://124972680> Reviewed by Mike Wyrzykowski. The code managing InteractionRegion layers in the RemoteLayerTree has a strict requirement for no <IntRect, InteractionRegion::Type> duplicate. We use the `m_interactionRects` / `m_occlusionRects` / `m_elementGuardRects` sets on the EventRegionContext to ensure this. But 275801@main introduced a code-path where we insert extra Interaction Regions for photos in `shrinkWrapInteractionRegions`. We need to maintain the no-duplicate rule there too. * Source/WebCore/rendering/EventRegion.cpp: (WebCore::EventRegionContext::shrinkWrapInteractionRegions): Make sure the extra regions "to add after merge" do not create <IntRect, InteractionRegion::Type> duplicates. Update the existing region's content hint instead. * LayoutTests/interaction-region/content-hint-overlap-dedupe-expected.txt: Added. * LayoutTests/interaction-region/content-hint-overlap-dedupe.html: Added. Add a test covering this and exercising the assertions in the RemoteLayerTree code. Canonical link: https://commits.webkit.org/276335@main
WebKit · Mar 19, 2024 · 3472dac · 3472dac
1 parent 86ebc77
commit 3472dac
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diff --git a/LayoutTests/interaction-region/content-hint-overlap-dedupe-expected.txt b/LayoutTests/interaction-region/content-hint-overlap-dedupe-expected.txt
@@ -0,0 +1,20 @@
+(GraphicsLayer
+  (anchor 0.00 0.00)
+  (bounds 800.00 600.00)
+  (children 1
+    (GraphicsLayer
+      (bounds 800.00 600.00)
+      (contentsOpaque 1)
+      (drawsContent 1)
+      (backgroundColor #FFFFFF)
+      (event region
+        (rect (0,0) width=800 height=600)
+
+      (interaction regions [
+        (interaction (0,0) width=400 height=300)
+        (content hint photo)])
+      )
+    )
+  )
+)
+
diff --git a/LayoutTests/interaction-region/content-hint-overlap-dedupe.html b/LayoutTests/interaction-region/content-hint-overlap-dedupe.html
@@ -0,0 +1,67 @@
+<!DOCTYPE html>
+<html>
+<style>
+    body { margin: 0; }
+
+    #interactive {
+        background: blue;
+    }
+    .rect {
+        position: absolute;
+        top: 0;
+        left: 0;
+        width: 400px;
+        height: 300px;
+        opacity: 0.5;
+    }
+    span {
+        position: absolute;
+        top: 200px;
+        left: 100px;
+    }
+</style>
+<script src="../resources/ui-helper.js"></script>
+<body>
+<section id="test">
+    <a href="#">
+        <div id="interactive" class="rect"></div>
+        <img src="../fast/media/resources/apple_logo_big.jpg" alt="apple logo" class="rect" />
+        <span>link</span>
+    </a>
+    <div id="counter"></div>
+</section>
+
+<pre id="results"></pre>
+<script>
+document.body.addEventListener("click", function(e) {
+    console.log(e, "event delegation");
+});
+
+if (window.testRunner) {
+    testRunner.waitUntilDone();
+    testRunner.dumpAsText();
+}
+
+window.onload = async function () {
+    if (!window.internals)
+        return;
+
+    await UIHelper.animationFrame();
+    await UIHelper.ensureStablePresentationUpdate();
+
+    // Re-render.
+    for (var i = 0; i <= 3; i++) {
+        document.getElementById("counter").textContent = i;
+        await UIHelper.animationFrame();
+        await UIHelper.ensureStablePresentationUpdate();
+    }
+
+    results.textContent = internals.layerTreeAsText(document, internals.LAYER_TREE_INCLUDES_EVENT_REGION | internals.LAYER_TREE_INCLUDES_ROOT_LAYER_PROPERTIES);
+    document.getElementById('test').remove();
+
+    testRunner.notifyDone();
+};
+</script>
+</body>
+</html>
+
diff --git a/Source/WebCore/rendering/EventRegion.cpp b/Source/WebCore/rendering/EventRegion.cpp
@@ -298,10 +298,16 @@ void EventRegionContext::shrinkWrapInteractionRegions()
             region.cornerRadius = 0;
         }
 
-        for (auto& region : toAddAfterMerge) {
-            auto rectForTracking = enclosingIntRect(region.rectInLayerCoordinates);
-            region.contentHint = m_interactionRectsAndContentHints.get(rectForTracking);
-            m_interactionRegions.insert(++i, WTFMove(region));
+        auto finalRegionRectForTracking = enclosingIntRect(region.rectInLayerCoordinates);
+        for (auto& extraRegion : toAddAfterMerge) {
+            auto extraRectForTracking = enclosingIntRect(extraRegion.rectInLayerCoordinates);
+            // Do not insert a new region if it creates a duplicated Interaction Rect.
+            if (finalRegionRectForTracking == extraRectForTracking) {
+                region.contentHint = m_interactionRectsAndContentHints.get(extraRectForTracking);
+                continue;
+            }
+            extraRegion.contentHint = m_interactionRectsAndContentHints.get(extraRectForTracking);
+            m_interactionRegions.insert(++i, WTFMove(extraRegion));
         }
     }
 }