Changeset 163157 in webkit

Timestamp:

Jan 30, 2014 9:42:25 PM (10 years ago)

Author:

Simon Fraser

Message:

Some fixed position elements disappear in WK2 on iOS
​https://bugs.webkit.org/show_bug.cgi?id=127977

Reviewed by Tim Horton.

Use the appropriate rectangle to ensure that on iOS we don't
consider a fixed element outside the viewport when zoomed in,
and therefore never make a compositing layer for it.

Also remove the iOS-specific code in RenderLayerCompositor::requiresCompositingForPosition(),
since it's OK to use the common code. Doing so requires that we
set the "acceleratedCompositingForFixedPositionEnabled" setting to true
for iOS, so do so.

• page/Settings.cpp:
• page/Settings.in:
• rendering/RenderLayerCompositor.cpp:

(WebCore::RenderLayerCompositor::requiresCompositingForPosition):

Location:

trunk/Source/WebCore

Files:

• ChangeLog (modified) (1 diff)
• page/Settings.cpp (modified) (2 diffs)
• page/Settings.in (modified) (1 diff)
• rendering/RenderLayerCompositor.cpp (modified) (3 diffs)

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2014-01-30  Simon Fraser  <simon.fraser@apple.com>
+
+        Some fixed position elements disappear in WK2 on iOS
+        https://bugs.webkit.org/show_bug.cgi?id=127977
+
+        Reviewed by Tim Horton.
+
+        Use the appropriate rectangle to ensure that on iOS we don't 
+        consider a fixed element outside the viewport when zoomed in,
+        and therefore never make a compositing layer for it.
+
+        Also remove the iOS-specific code in RenderLayerCompositor::requiresCompositingForPosition(),
+        since it's OK to use the common code. Doing so requires that we
+        set the "acceleratedCompositingForFixedPositionEnabled" setting to true
+        for iOS, so do so.
+
+        * page/Settings.cpp:
+        * page/Settings.in:
+        * rendering/RenderLayerCompositor.cpp:
+        (WebCore::RenderLayerCompositor::requiresCompositingForPosition):
+
 2014-01-30  Zalan Bujtas  <zalan@apple.com>
 

trunk/Source/WebCore/page/Settings.cpp

@@ -125 +125 @@
 #if PLATFORM(IOS)
 static const bool defaultFixedPositionCreatesStackingContext = true;
+static const bool defaultAcceleratedCompositingForFixedPositionEnabled = true;
 static const bool defaultMediaPlaybackAllowsInline = false;
 static const bool defaultMediaPlaybackRequiresUserGesture = true;
@@ -130 +131 @@
 #else
 static const bool defaultFixedPositionCreatesStackingContext = false;
+static const bool defaultAcceleratedCompositingForFixedPositionEnabled = false;
 static const bool defaultMediaPlaybackAllowsInline = true;
 static const bool defaultMediaPlaybackRequiresUserGesture = false;

trunk/Source/WebCore/page/Settings.in

@@ -96 +96 @@
 xssAuditorEnabled initial=false
 unsafePluginPastingEnabled initial=true
-acceleratedCompositingForFixedPositionEnabled initial=false
+acceleratedCompositingForFixedPositionEnabled initial=defaultAcceleratedCompositingForFixedPositionEnabled
 acceleratedCompositingForOverflowScrollEnabled initial=false
 

trunk/Source/WebCore/rendering/RenderLayerCompositor.cpp

@@ -2496 +2496 @@
 bool RenderLayerCompositor::requiresCompositingForPosition(RenderLayerModelObject& renderer, const RenderLayer& layer, RenderLayer::ViewportConstrainedNotCompositedReason* viewportConstrainedNotCompositedReason) const
 {
-#if PLATFORM(IOS)
-    if (renderer.isStickyPositioned())
-        return true;
-
-    // position:fixed elements that create their own stacking context (e.g. have an explicit z-index,
-    // opacity, transform) can get their own composited layer. A stacking context is required otherwise
-    // z-index and clipping will be broken.
-    if (!(renderer.isOutOfFlowPositioned() && renderer.style().position() == FixedPosition))
-        return false;
-
-    if (!m_renderView.hasCustomFixedPosition(renderer, RenderView::CheckContainingBlock)) {
-        m_reevaluateCompositingAfterLayout = true;
-        return false;
-    }
-#else
     // position:fixed elements that create their own stacking context (e.g. have an explicit z-index,
     // opacity, transform) can get their own composited layer. A stacking context is required otherwise
@@ -2533 +2518 @@
     if (isSticky)
         return hasCoordinatedScrolling() && isViewportConstrainedFixedOrStickyLayer(layer);
-#endif
 
     auto container = renderer.container();
@@ -2564 +2548 @@
 
     // Fixed position elements that are invisible in the current view don't get their own layer.
-    LayoutRect viewBounds = m_renderView.frameView().viewportConstrainedVisibleContentRect();
+    LayoutRect viewBounds = m_renderView.frameView().viewportConstrainedExtentRect();
     LayoutRect layerBounds = layer.calculateLayerBounds(&layer, 0, RenderLayer::UseLocalClipRectIfPossible | RenderLayer::IncludeLayerFilterOutsets | RenderLayer::UseFragmentBoxes
         | RenderLayer::ExcludeHiddenDescendants | RenderLayer::DontConstrainForMask | RenderLayer::IncludeCompositedDescendants);