Changeset 199821 in webkit

Timestamp:

Apr 21, 2016 10:02:57 AM (8 years ago)

Author:

commit-queue@webkit.org

Message:

REGRESSION(198782): ImageSource::subsamplingLevelForScale() does not cache the MaximumSubsamplingLevel for this ImageSource
​https://bugs.webkit.org/show_bug.cgi?id=156766

Patch by Said Abou-Hallawa <​sabouhallawa@apple.com> on 2016-04-21
Reviewed by Darin Adler.

Ensure the MaximumSubsamplingLevel for the ImageSource is calculated
only once and is cached for subsequent uses.

The image subsampling is on by default only for iOS. So the and this
patch currently affects the iOS port.

• platform/graphics/ImageSource.cpp:

(WebCore::ImageSource::cacheMetadata): Cache m_maximumSubsamplingLevel.
Use m_frameCount as a flag for having_the_cache_done.
(WebCore::ImageSource::subsamplingLevelForScale): Call cacheMetadata()
before using m_maximumSubsamplingLevel.
(WebCore::ImageSource::frameCount): Call cacheMetadata() before returning
m_frameCount.

• platform/graphics/ImageSource.h:

Location:

trunk/Source/WebCore

Files:

• ChangeLog (modified) (1 diff)
• platform/graphics/ImageSource.cpp (modified) (2 diffs)
• platform/graphics/ImageSource.h (modified) (3 diffs)

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2016-04-21  Said Abou-Hallawa  <sabouhallawa@apple.com>
+
+        REGRESSION(198782): ImageSource::subsamplingLevelForScale() does not cache the MaximumSubsamplingLevel for this ImageSource
+        https://bugs.webkit.org/show_bug.cgi?id=156766
+
+        Reviewed by Darin Adler.
+
+        Ensure the MaximumSubsamplingLevel for the ImageSource is calculated
+        only once and is cached for subsequent uses. 
+        
+        The image subsampling is on by default only for iOS. So the and this
+        patch currently affects the iOS port.
+
+        * platform/graphics/ImageSource.cpp:
+        (WebCore::ImageSource::cacheMetadata): Cache m_maximumSubsamplingLevel.
+        Use m_frameCount as a flag for having_the_cache_done.
+        (WebCore::ImageSource::subsamplingLevelForScale): Call cacheMetadata()
+        before using m_maximumSubsamplingLevel.
+        (WebCore::ImageSource::frameCount): Call cacheMetadata() before returning
+        m_frameCount.
+        * platform/graphics/ImageSource.h:
+
 2016-04-21  Antoine Quint  <graouts@apple.com>
 

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

@@ -105 +105 @@
 }
 
-SubsamplingLevel ImageSource::subsamplingLevelForScale(float scale) const
+void ImageSource::cacheMetadata()
+{
+    if (m_frameCount || !isSizeAvailable())
+        return;
+    
+    m_frameCount = m_decoder->frameCount();
+    m_maximumSubsamplingLevel = calculateMaximumSubsamplingLevel();
+}
+    
+SubsamplingLevel ImageSource::subsamplingLevelForScale(float scale)
 {
     if (!(scale > 0 && scale <= 1))
         return 0;
     
-    SubsamplingLevel maximumSubsamplingLevel = calculateMaximumSubsamplingLevel();
-    if (!maximumSubsamplingLevel)
+    cacheMetadata();
+    if (!m_maximumSubsamplingLevel)
         return 0;
 
     // There are four subsampling levels: 0 = 1x, 1 = 0.5x, 2 = 0.25x, 3 = 0.125x.
     SubsamplingLevel result = std::ceil(std::log2(1 / scale));
-    return std::min(result, maximumSubsamplingLevel);
+    return std::min(result, m_maximumSubsamplingLevel);
 }
 
@@ -139 +148 @@
 }
 
-size_t ImageSource::frameCount() const
-{
-    return initialized() ? m_decoder->frameCount() : 0;
+size_t ImageSource::frameCount()
+{
+    cacheMetadata();
+    return m_frameCount;
 }
 

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

@@ -111 +111 @@
     void setData(SharedBuffer* data, bool allDataReceived);
 
-    SubsamplingLevel subsamplingLevelForScale(float) const;
+    SubsamplingLevel subsamplingLevelForScale(float);
     void setAllowSubsampling(bool allowSubsampling) { m_allowSubsampling = allowSubsampling; }
     static size_t bytesDecodedToDetermineProperties();
@@ -120 +120 @@
     IntSize sizeRespectingOrientation() const;
 
-    size_t frameCount() const;
+    size_t frameCount();
     int repetitionCount();
     String filenameExtension() const;
@@ -146 +146 @@
     void clearFrameBufferCache(size_t);
     SubsamplingLevel calculateMaximumSubsamplingLevel() const;
+    void cacheMetadata();
     void dump(TextStream&) const;
     
     std::unique_ptr<ImageDecoder> m_decoder;
+    
+    size_t m_frameCount { 0 };
+    SubsamplingLevel m_maximumSubsamplingLevel { 0 };
 
     // The default value of m_allowSubsampling should be the same as defaultImageSubsamplingEnabled in Settings.cpp