Changeset 252419 in webkit

Timestamp:

Nov 13, 2019, 11:22:54 AM (7 years ago)

Author:

Antti Koivisto

Message:

Google Docs spreadsheet tiles render very slowly (because of event region painting)
​https://bugs.webkit.org/show_bug.cgi?id=204160
<rdar://problem/57073401>

Reviewed by Simon Fraser.

Source/WebCore:

Content of a overflow:scroll area on this page doesn't cover the entire scrollable area and we end
up generating a complex shape for the event region. This is unnecessary as touches within scrollers
always scroll the content.

Test: fast/scrolling/ios/event-region-scrolled-contents-layer.html

• rendering/RenderLayerBacking.cpp:

(WebCore::RenderLayerBacking::updateEventRegion):

Initialize event region for scrolled contents layer with layer-sized event region. This optimizes away
event region mutations. We still need to to do the event region paint to capture touch-action regions.

In future we should also improve Region type to not have pathological worst-case performance with complex
shapes.

LayoutTests:

• fast/scrolling/ios/event-region-scrolled-contents-layer-expected.txt: Added.
• fast/scrolling/ios/event-region-scrolled-contents-layer.html: Added.

Location:

trunk

Files:

• LayoutTests/ChangeLog (modified) (1 diff)
• LayoutTests/fast/scrolling/ios/event-region-scrolled-contents-layer-expected.txt (added)
• LayoutTests/fast/scrolling/ios/event-region-scrolled-contents-layer.html (added)
• Source/WebCore/ChangeLog (modified) (1 diff)
• Source/WebCore/rendering/RenderLayerBacking.cpp (modified) (1 diff)

trunk/LayoutTests/ChangeLog

@@ +1 @@
+2019-11-13  Antti Koivisto  <antti@apple.com>
+
+        Google Docs spreadsheet tiles render very slowly (because of event region painting)
+        https://bugs.webkit.org/show_bug.cgi?id=204160
+        <rdar://problem/57073401>
+
+        Reviewed by Simon Fraser.
+
+        * fast/scrolling/ios/event-region-scrolled-contents-layer-expected.txt: Added.
+        * fast/scrolling/ios/event-region-scrolled-contents-layer.html: Added.
+
 2019-11-13  Youenn Fablet  <youenn@apple.com>
 

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2019-11-13  Antti Koivisto  <antti@apple.com>
+
+        Google Docs spreadsheet tiles render very slowly (because of event region painting)
+        https://bugs.webkit.org/show_bug.cgi?id=204160
+        <rdar://problem/57073401>
+
+        Reviewed by Simon Fraser.
+
+        Content of a overflow:scroll area on this page doesn't cover the entire scrollable area and we end
+        up generating a complex shape for the event region. This is unnecessary as touches within scrollers
+        always scroll the content.
+
+        Test: fast/scrolling/ios/event-region-scrolled-contents-layer.html
+
+        * rendering/RenderLayerBacking.cpp:
+        (WebCore::RenderLayerBacking::updateEventRegion):
+
+        Initialize event region for scrolled contents layer with layer-sized event region. This optimizes away
+        event region mutations. We still need to to do the event region paint to capture touch-action regions.
+
+        In future we should also improve Region type to not have pathological worst-case performance with complex
+        shapes.
+
 2019-11-13  Andres Gonzalez  <andresg_22@apple.com>
 

trunk/Source/WebCore/rendering/RenderLayerBacking.cpp

@@ -1600 +1600 @@
         EventRegion eventRegion;
         auto eventRegionContext = eventRegion.makeContext();
+        auto layerOffset = graphicsLayer.scrollOffset() - roundedIntSize(graphicsLayer.offsetFromRenderer());
+
+        if (&graphicsLayer == m_scrolledContentsLayer && renderer().visibleToHitTesting()) {
+            // Initialize scrolled contents layer with layer-sized event region as it can all used for scrolling.
+            // This avoids generating unnecessarily complex event regions. We still need to to do the paint to capture touch-action regions.
+            eventRegionContext.unite(enclosingIntRect(FloatRect(-layerOffset, graphicsLayer.size())), RenderStyle::defaultStyle());
+        }
+
         auto dirtyRect = enclosingIntRect(FloatRect(FloatPoint(graphicsLayer.offsetFromRenderer()), graphicsLayer.size()));
-
         paintIntoLayer(&graphicsLayer, nullContext, dirtyRect, { }, &eventRegionContext);
 
-        auto layerOffset = toIntSize(graphicsLayer.scrollOffset()) - roundedIntSize(graphicsLayer.offsetFromRenderer());
-        eventRegion.translate(layerOffset);
+        eventRegion.translate(toIntSize(layerOffset));
 
         graphicsLayer.setEventRegion(WTFMove(eventRegion));