Changeset 202348 in webkit

Timestamp:

Jun 22, 2016, 1:44:26 PM (9 years ago)

Author:

Simon Fraser

Message:

REGRESSION (r201629): Weird button glitching on github.com
​https://bugs.webkit.org/show_bug.cgi?id=159031
rdar://problem/26880332

Reviewed by Tim Horton.

Source/WebCore:

r201629 changed the logic slightly when creating an image buffer for a scaled context;
it set the buffer context's scale to the scale in the source context, but this failed
to take into account the rounding up of the buffer size, which the old code did.

Fix by reverting to the old behavior.

Since buffer sizes can only be integral, changed compatibleBufferSize() to return
an IntSize.

Test: fast/backgrounds/scaled-gradient-background.html

• platform/graphics/ImageBuffer.cpp:

(WebCore::ImageBuffer::createCompatibleBuffer):
(WebCore::ImageBuffer::compatibleBufferSize):

• platform/graphics/ImageBuffer.h:
• platform/graphics/IntRect.h:

(WebCore::IntRect::area):

• platform/graphics/IntSize.h:

(WebCore::IntSize::area): Make this return an unsigned.

LayoutTests:

• fast/backgrounds/scaled-gradient-background-expected.html: Added.
• fast/backgrounds/scaled-gradient-background.html: Added.

Location:

trunk

Files:

• LayoutTests/ChangeLog (modified) (1 diff)
• LayoutTests/fast/backgrounds/scaled-gradient-background-expected.html (added)
• LayoutTests/fast/backgrounds/scaled-gradient-background.html (added)
• Source/WebCore/ChangeLog (modified) (1 diff)
• Source/WebCore/platform/graphics/ImageBuffer.cpp (modified) (2 diffs)
• Source/WebCore/platform/graphics/ImageBuffer.h (modified) (1 diff)
• Source/WebCore/platform/graphics/IntRect.h (modified) (1 diff)
• Source/WebCore/platform/graphics/IntSize.h (modified) (1 diff)

trunk/LayoutTests/ChangeLog

@@ +1 @@
+2016-06-22  Simon Fraser  <simon.fraser@apple.com>
+
+        REGRESSION (r201629): Weird button glitching on github.com
+        https://bugs.webkit.org/show_bug.cgi?id=159031
+        rdar://problem/26880332
+
+        Reviewed by Tim Horton.
+
+        * fast/backgrounds/scaled-gradient-background-expected.html: Added.
+        * fast/backgrounds/scaled-gradient-background.html: Added.
+
 2016-06-22  Alexey Proskuryakov  <ap@apple.com>
 

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2016-06-22  Simon Fraser  <simon.fraser@apple.com>
+
+        REGRESSION (r201629): Weird button glitching on github.com
+        https://bugs.webkit.org/show_bug.cgi?id=159031
+        rdar://problem/26880332
+
+        Reviewed by Tim Horton.
+
+        r201629 changed the logic slightly when creating an image buffer for a scaled context;
+        it set the buffer context's scale to the scale in the source context, but this failed
+        to take into account the rounding up of the buffer size, which the old code did.
+
+        Fix by reverting to the old behavior.
+
+        Since buffer sizes can only be integral, changed compatibleBufferSize() to return
+        an IntSize.
+
+        Test: fast/backgrounds/scaled-gradient-background.html
+
+        * platform/graphics/ImageBuffer.cpp:
+        (WebCore::ImageBuffer::createCompatibleBuffer):
+        (WebCore::ImageBuffer::compatibleBufferSize):
+        * platform/graphics/ImageBuffer.h:
+        * platform/graphics/IntRect.h:
+        (WebCore::IntRect::area):
+        * platform/graphics/IntSize.h:
+        (WebCore::IntSize::area): Make this return an unsigned.
+
 2016-06-22  Anders Carlsson  <andersca@apple.com>
 

trunk/Source/WebCore/platform/graphics/ImageBuffer.cpp

@@ -170 +170 @@
         return nullptr;
 
-    FloatSize scaledSize = ImageBuffer::compatibleBufferSize(size, context);
-
-    auto buffer = ImageBuffer::createCompatibleBuffer(expandedIntSize(scaledSize), 1, ColorSpaceSRGB, context, hasAlpha);
+    IntSize scaledSize = ImageBuffer::compatibleBufferSize(size, context);
+
+    auto buffer = ImageBuffer::createCompatibleBuffer(scaledSize, 1, ColorSpaceSRGB, context, hasAlpha);
     if (!buffer)
         return nullptr;
 
     // Set up a corresponding scale factor on the graphics context.
-    buffer->context().scale(context.scaleFactor());
+    buffer->context().scale(FloatSize(scaledSize.width() / size.width(), scaledSize.height() / size.height()));
     return buffer;
 }
@@ -186 +186 @@
 }
 
-FloatSize ImageBuffer::compatibleBufferSize(const FloatSize& size, const GraphicsContext& context)
+IntSize ImageBuffer::compatibleBufferSize(const FloatSize& size, const GraphicsContext& context)
 {
     // Enlarge the buffer size if the context's transform is scaling it so we need a higher
     // resolution than one pixel per unit.
-    return size * context.scaleFactor();
+    return expandedIntSize(size * context.scaleFactor());
 }
 

trunk/Source/WebCore/platform/graphics/ImageBuffer.h

@@ -84 +84 @@
     static std::unique_ptr<ImageBuffer> createCompatibleBuffer(const FloatSize&, float resolutionScale, ColorSpace, const GraphicsContext&, bool hasAlpha);
 
-    static FloatSize compatibleBufferSize(const FloatSize&, const GraphicsContext&);
+    static IntSize compatibleBufferSize(const FloatSize&, const GraphicsContext&);
     bool isCompatibleWithContext(const GraphicsContext&) const;
 

trunk/Source/WebCore/platform/graphics/IntRect.h

@@ -86 +86 @@
     int width() const { return m_size.width(); }
     int height() const { return m_size.height(); }
+    
+    unsigned area() const { return m_size.area(); }
 
     void setX(int x) { m_location.setX(x); }

trunk/Source/WebCore/platform/graphics/IntSize.h

@@ -126 +126 @@
     IntSize constrainedBetween(const IntSize& min, const IntSize& max) const;
 
-    int area() const
-    {
-        return m_width * m_height;
+    unsigned area() const
+    {
+        return abs(m_width) * abs(m_height);
     }