Changeset 249352 in webkit

Timestamp:

Aug 30, 2019 5:29:02 PM (5 years ago)

Author:

Simon Fraser

Message:

Minor optimization in determineNonLayerDescendantsPaintedContent()
​https://bugs.webkit.org/show_bug.cgi?id=201352

Reviewed by Antti Koivisto.

It's cheaper to call renderText.hasRenderedText() than renderText.linesBoundingBox(), because
the latter has to traverse all the InlineTextBoxes. This code path is fairly hot when
scrolling twitter feeds, since it's called from RenderLayer::updateLayerPositionsAfterScroll()
which calls RenderLayer::isVisuallyNonEmpty().

• rendering/RenderLayer.cpp:

(WebCore::RenderLayer::calculateClipRects const):

Location:

trunk/Source/WebCore

Files:

• ChangeLog (modified) (1 diff)
• rendering/RenderLayer.cpp (modified) (1 diff)

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2019-08-30  Simon Fraser  <simon.fraser@apple.com>
+
+        Minor optimization in determineNonLayerDescendantsPaintedContent()
+        https://bugs.webkit.org/show_bug.cgi?id=201352
+
+        Reviewed by Antti Koivisto.
+
+        It's cheaper to call renderText.hasRenderedText() than renderText.linesBoundingBox(), because
+        the latter has to traverse all the InlineTextBoxes. This code path is fairly hot when
+        scrolling twitter feeds, since it's called from RenderLayer::updateLayerPositionsAfterScroll()
+        which calls RenderLayer::isVisuallyNonEmpty().
+
+        * rendering/RenderLayer.cpp:
+        (WebCore::RenderLayer::calculateClipRects const):
+
 2019-08-30  Saam Barati  <sbarati@apple.com>
 

trunk/Source/WebCore/rendering/RenderLayer.cpp

@@ -6401 +6401 @@
         if (is<RenderText>(child)) {
             const auto& renderText = downcast<RenderText>(child);
-            if (renderText.linesBoundingBox().isEmpty())
+            if (!renderText.hasRenderedText())
                 continue;