Changeset 261979 in webkit

Timestamp:

May 20, 2020, 6:44:12 PM (5 years ago)

Author:

Alan Bujtas

Message:

Repaint issues when the login field collapses on music.apple.com
​https://bugs.webkit.org/show_bug.cgi?id=212101
<rdar://problem/62874369>

Reviewed by Simon Fraser.

Source/WebCore:

RenderWidgets (e.g iframe) are painted on integral pixel boundaries. When we issue the repaints on such renderers, we need to
make sure that the repaint rectangles are also snapped to integral pixel values.
Currently trunk only covers the case when the renderer itself is positioned on a subpixel position (e.g when the containing block's content box has a non-integral position value).
This patch ensures that we repaint the RenderWidgets properly when a non-direct ancestor puts the renderer on a subpixel position.

Test: fast/repaint/iframe-on-subpixel-position.html

• page/FrameView.h:
• rendering/RenderBox.cpp:

(WebCore::RenderBox::computeVisibleRectInContainer const):

• rendering/RenderLayerBacking.cpp:

(WebCore::RenderLayerBacking::setContentsNeedDisplay):
(WebCore::RenderLayerBacking::setContentsNeedDisplayInRect):

• rendering/RenderObject.h:
• testing/Internals.cpp:

(WebCore::Internals::enableSubframeRepaintTracking): add subframe repaint tracking
(WebCore::Internals::disableSubframeRepaintTracking):

• testing/Internals.h:
• testing/Internals.idl:

LayoutTests:

• fast/repaint/iframe-on-subpixel-position-expected.txt: Added.
• fast/repaint/iframe-on-subpixel-position.html: Added.

Location:

trunk

Files:

• LayoutTests/ChangeLog (modified) (1 diff)
• LayoutTests/fast/repaint/iframe-on-subpixel-position-expected.txt (added)
• LayoutTests/fast/repaint/iframe-on-subpixel-position.html (added)
• Source/WebCore/ChangeLog (modified) (1 diff)
• Source/WebCore/rendering/RenderBox.cpp (modified) (2 diffs)
• Source/WebCore/rendering/RenderObject.h (modified) (1 diff)

trunk/LayoutTests/ChangeLog

@@ +1 @@
+2020-05-20  Zalan Bujtas  <zalan@apple.com>
+
+        Repaint issues when the login field collapses on music.apple.com
+        https://bugs.webkit.org/show_bug.cgi?id=212101
+        <rdar://problem/62874369>
+
+        Reviewed by Simon Fraser.
+
+        * fast/repaint/iframe-on-subpixel-position-expected.txt: Added.
+        * fast/repaint/iframe-on-subpixel-position.html: Added.
+
 2020-05-20  Kenneth Russell  <kbr@chromium.org>
 

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2020-05-20  Zalan Bujtas  <zalan@apple.com>
+
+        Repaint issues when the login field collapses on music.apple.com
+        https://bugs.webkit.org/show_bug.cgi?id=212101
+        <rdar://problem/62874369>
+
+        Reviewed by Simon Fraser.
+
+        RenderWidgets (e.g iframe) are painted on integral pixel boundaries. When we issue the repaints on such renderers, we need to
+        make sure that the repaint rectangles are also snapped to integral pixel values.
+        Currently trunk only covers the case when the renderer itself is positioned on a subpixel position (e.g when the containing block's content box has a non-integral position value).
+        This patch ensures that we repaint the RenderWidgets properly when a non-direct ancestor puts the renderer on a subpixel position.
+
+        Test: fast/repaint/iframe-on-subpixel-position.html
+
+        * page/FrameView.h:
+        * rendering/RenderBox.cpp:
+        (WebCore::RenderBox::computeVisibleRectInContainer const):
+        * rendering/RenderLayerBacking.cpp:
+        (WebCore::RenderLayerBacking::setContentsNeedDisplay):
+        (WebCore::RenderLayerBacking::setContentsNeedDisplayInRect):
+        * rendering/RenderObject.h:
+        * testing/Internals.cpp:
+        (WebCore::Internals::enableSubframeRepaintTracking): add subframe repaint tracking 
+        (WebCore::Internals::disableSubframeRepaintTracking):
+        * testing/Internals.h:
+        * testing/Internals.idl:
+
 2020-05-20  Oriol Brufau  <obrufau@igalia.com>
 

trunk/Source/WebCore/rendering/RenderBox.cpp

@@ -2278 +2278 @@
         if (container->style().isFlippedBlocksWritingMode())
             flipForWritingMode(adjustedRect);
+        if (context.descendantNeedsEnclosingIntRect)
+            adjustedRect = enclosingIntRect(adjustedRect);
         return adjustedRect;
     }
@@ -2314 +2316 @@
         adjustedRect.expand(locationOffset - flooredLocationOffset);
         locationOffset = flooredLocationOffset;
+        context.descendantNeedsEnclosingIntRect = true;
     }
 

trunk/Source/WebCore/rendering/RenderObject.h

@@ -625 +625 @@
             {
             }
-        bool hasPositionFixedDescendant;
-        bool dirtyRectIsFlipped;
+        bool hasPositionFixedDescendant { false };
+        bool dirtyRectIsFlipped { false };
+        bool descendantNeedsEnclosingIntRect { false };
         OptionSet<VisibleRectContextOption> options;
     };