[Apple] Use Accelerate framework to speed-up FEGaussianBlur

[WebKit-https.git] / Source / WebCore / ChangeLog

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+2014-12-08  Dean Jackson  <dino@apple.com>
+
+        [Apple] Use Accelerate framework to speed-up FEGaussianBlur
+        https://bugs.webkit.org/show_bug.cgi?id=139310
+        <rdar://problem/18434594>
+
+        Reviewed by Simon Fraser.
+
+        Using Apple's Accelerate framework provides faster blurs
+        than the parallel jobs approach, especially since r168577
+        which started performing retina-accurate filters.
+
+        Using Accelerate.framework to replace the existing box blur (what
+        we use to approximate Gaussian blurs) gets about a 20% speedup on
+        desktop class machines, but between a 2x-6x speedup on iOS hardware.
+        Obviously this depends on the size of the content being blurred,
+        but it is still good.
+
+        The change is to intercept the platformApply function on
+        FEGaussianBlur and send it off to Accelerate.
+
+        There is an interactive performance test: PerformanceTests/Interactive/blur-filter-timing.html
+
+        * platform/graphics/filters/FEGaussianBlur.cpp:
+        (WebCore::kernelPosition): Move this to a file static function from the .h.
+        (WebCore::accelerateBoxBlur): The Accelerate implementation.
+        (WebCore::standardBoxBlur): The default generic/standard implementation.
+        (WebCore::FEGaussianBlur::platformApplyGeneric): Use accelerate or the default form.
+        (WebCore::FEGaussianBlur::platformApply): Don't try the parallelJobs approach if Accelerate is available.
+        * platform/graphics/filters/FEGaussianBlur.h:
+        (WebCore::FEGaussianBlur::kernelPosition): Deleted. Move into the .cpp.
+
 2014-12-08  Beth Dakin  <bdakin@apple.com>
 
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