Changeset 181695 in webkit

Timestamp:

Mar 18, 2015, 9:22:04 AM (11 years ago)

Author:

Simon Fraser

Message:

Skip trying to paint overlay scrollbars when there are none or they are clipped out
​https://bugs.webkit.org/show_bug.cgi?id=142811
rdar://problem/20200725

Reviewed by Darin Adler.

In some content with lots of layers and overflow:scroll, we could spend 20% of
the time under paintOverflowControlsForFragments() setting up an (empty) clip,
and then trying to draw scrollbars that we don't have.

Avoid calling paintOverflowControlsForFragments() if there are no scrollbars,
and don't both setting up an empty clip just to paint nothing.

• rendering/RenderLayer.cpp:

(WebCore::RenderLayer::paintLayerContents):
(WebCore::RenderLayer::paintOverflowControlsForFragments):

Location:

trunk/Source/WebCore

Files:

• ChangeLog (modified) (1 diff)
• rendering/RenderLayer.cpp (modified) (8 diffs)

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2015-03-17  Simon Fraser  <simon.fraser@apple.com>
+
+        Skip trying to paint overlay scrollbars when there are none or they are clipped out
+        https://bugs.webkit.org/show_bug.cgi?id=142811
+        rdar://problem/20200725
+
+        Reviewed by Darin Adler.
+
+        In some content with lots of layers and overflow:scroll, we could spend 20% of
+        the time under paintOverflowControlsForFragments() setting up an (empty) clip,
+        and then trying to draw scrollbars that we don't have.
+        
+        Avoid calling paintOverflowControlsForFragments() if there are no scrollbars,
+        and don't both setting up an empty clip just to paint nothing.
+
+        * rendering/RenderLayer.cpp:
+        (WebCore::RenderLayer::paintLayerContents):
+        (WebCore::RenderLayer::paintOverflowControlsForFragments):
+
 2015-03-18  Per Arne Vollan  <peavo@outlook.com>
 

trunk/Source/WebCore/rendering/RenderLayer.cpp

@@ -4320 +4320 @@
     }
 
-    if (isPaintingOverlayScrollbars)
+    if (isPaintingOverlayScrollbars && hasScrollbars())
         paintOverflowControlsForFragments(layerFragments, context, localPaintingInfo);
 
@@ -4616 +4616 @@
     RenderObject* subtreePaintRootForRenderer)
 {
-    for (size_t i = 0; i < layerFragments.size(); ++i) {
-        const LayerFragment& fragment = layerFragments.at(i);
+    for (const auto& fragment : layerFragments) {
         if (!fragment.shouldPaintContent)
             continue;
@@ -4647 +4646 @@
     // Begin transparency if we have something to paint.
     if (haveTransparency) {
-        for (size_t i = 0; i < layerFragments.size(); ++i) {
-            const LayerFragment& fragment = layerFragments.at(i);
+        for (const auto& fragment : layerFragments) {
             if (fragment.shouldPaintContent && !fragment.foregroundRect.isEmpty()) {
                 beginTransparencyLayers(transparencyLayerContext, localPaintingInfo, transparencyPaintDirtyRect);
@@ -4704 +4702 @@
     bool shouldClip = localPaintingInfo.clipToDirtyRect && layerFragments.size() > 1;
 
-    for (size_t i = 0; i < layerFragments.size(); ++i) {
-        const LayerFragment& fragment = layerFragments.at(i);
+    for (const auto& fragment : layerFragments) {
         if (!fragment.shouldPaintContent || fragment.foregroundRect.isEmpty())
             continue;
@@ -4725 +4722 @@
     PaintBehavior paintBehavior, RenderObject* subtreePaintRootForRenderer)
 {
-    for (size_t i = 0; i < layerFragments.size(); ++i) {
-        const LayerFragment& fragment = layerFragments.at(i);
+    for (const auto& fragment : layerFragments) {
         if (fragment.outlineRect.isEmpty())
             continue;
@@ -4741 +4737 @@
     RenderObject* subtreePaintRootForRenderer)
 {
-    for (size_t i = 0; i < layerFragments.size(); ++i) {
-        const LayerFragment& fragment = layerFragments.at(i);
+    for (const auto& fragment : layerFragments) {
         if (!fragment.shouldPaintContent)
             continue;
@@ -4762 +4757 @@
     RenderObject* subtreePaintRootForRenderer)
 {
-    for (size_t i = 0; i < layerFragments.size(); ++i) {
-        const LayerFragment& fragment = layerFragments.at(i);
+    for (const auto& fragment : layerFragments) {
         if (!fragment.shouldPaintContent)
             continue;
@@ -4781 +4775 @@
 void RenderLayer::paintOverflowControlsForFragments(const LayerFragments& layerFragments, GraphicsContext* context, const LayerPaintingInfo& localPaintingInfo)
 {
-    for (size_t i = 0; i < layerFragments.size(); ++i) {
-        const LayerFragment& fragment = layerFragments.at(i);
+    for (const auto& fragment : layerFragments) {
+        if (fragment.backgroundRect.isEmpty())
+            continue;
         clipToRect(localPaintingInfo, context, fragment.backgroundRect);
         paintOverflowControls(context, roundedIntPoint(toLayoutPoint(fragment.layerBounds.location() - renderBoxLocation() + localPaintingInfo.subpixelAccumulation)),