Save a bitmap copy when advancing to dependent GIF and WebP animation frames

third_party/WebKit/Source/platform/image-decoders/ImageFrame.cpp

 /*
  * Copyright (C) 2006 Apple Computer, Inc.  All rights reserved.
  * Copyright (C) 2008, 2009 Google, Inc.
  *
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  * modification, are permitted provided that the following conditions
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  * 1. Redistributions of source code must retain the above copyright
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  *    notice, this list of conditions and the following disclaimer in the
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  *
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  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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 #include "platform/image-decoders/ImageFrame.h"
 
 #include "platform/RuntimeEnabledFeatures.h"
+#include "platform/graphics/skia/SkiaUtils.h"
 #include "platform/image-decoders/ImageDecoder.h"
 
 namespace blink {
 
 ImageFrame::ImageFrame()
     : m_allocator(0)
     , m_hasAlpha(true)
     , m_status(FrameEmpty)
     , m_duration(0)
     , m_disposalMethod(DisposeNotSpecified)
@@ skipping 49 matching lines @@
 bool ImageFrame::copyBitmapData(const ImageFrame& other)
 {
     if (this == &other)
         return true;
 
     m_hasAlpha = other.m_hasAlpha;
     m_bitmap.reset();
     return other.m_bitmap.copyTo(&m_bitmap, other.m_bitmap.colorType());
 }
 
+bool ImageFrame::takeBitmapDataIfWritable(ImageFrame* other)
+{
+    DCHECK(other);
+    if (other->m_bitmap.isImmutable() || this == other)

[Peter Kasting, 2016/08/30 06:59:40]

Tiny efficiency nit: Reverse order of checks

[aleksandar.stojiljkovic, 2016/09/21 20:56:57]

It isn't obvious when/if this could happen (this == other) so while debugging
most common use cases I found that the current order is leaving the check
earlier.

"this == other" I copied from copyBitmapData.

[Peter Kasting, 2016/09/21 21:54:49]

I suppose you could make this (and maybe that function also?) DCHECK that this
!= other, if it never makes sense for that to happen (which it probably
doesn't).

[aleksandar.stojiljkovic, 2016/09/22 09:41:19]

Done.

+        return false;
+    m_hasAlpha = other->m_hasAlpha;
+    m_bitmap.reset();
+    m_bitmap.swap(other->m_bitmap);
+    other->m_status = FrameEmpty;
+    return true;
+}
+
 bool ImageFrame::setSizeAndColorProfile(int newWidth, int newHeight, const ICCProfile& newIccProfile)
 {
     // setSizeAndColorProfile() should only be called once, it leaks memory otherwise.
     ASSERT(!width() && !height());
 
     sk_sp<SkColorSpace> colorSpace;
     if (RuntimeEnabledFeatures::colorCorrectRenderingEnabled() && !newIccProfile.isEmpty())
         colorSpace = SkColorSpace::NewICC(newIccProfile.data(), newIccProfile.size());
 
     m_bitmap.setInfo(SkImageInfo::MakeN32(newWidth, newHeight,
         m_premultiplyAlpha ? kPremul_SkAlphaType : kUnpremul_SkAlphaType, colorSpace));
     if (!m_bitmap.tryAllocPixels(m_allocator, 0))
         return false;
 
     zeroFillPixelData();
     return true;
 }
 
 bool ImageFrame::hasAlpha() const
 {
     return m_hasAlpha;
 }
 
+const SkBitmap& ImageFrame::bitmap() const
+{
+    // We don't want to set the status to immutable here as we do in
+    // finalizePixelsAndGetImage() because mutable bitmap is reusable as the
+    // next animation frame by calling takeBitmapDataIfWritable.

[Peter Kasting, 2016/08/30 06:59:40]

Nit: The header comments should already justify any functional difference
between these two, so I'd remove this comment and just inline the method into
the header.

[aleksandar.stojiljkovic, 2016/09/21 20:56:57]

Done.

+    return m_bitmap;
+}
+
+PassRefPtr<SkImage> ImageFrame::finalizePixelsAndGetImage()
+{
+    DCHECK(m_status != FrameComplete || (!m_bitmap.isNull() && !m_bitmap.empty()));
+
+    // We don't set the status to immutable until there is a request to get
+    // SkImage and decoding is done.  We set the bitmap to immutable here to
+    // avoid copying in SkImage::MakeFromBitmap.
+    if (!m_bitmap.isImmutable() && m_status == FrameComplete)
+        m_bitmap.setImmutable();
+    return fromSkSp(SkImage::MakeFromBitmap(m_bitmap));
+}
+
 void ImageFrame::setHasAlpha(bool alpha)
 {
     m_hasAlpha = alpha;
 
     m_bitmap.setAlphaType(computeAlphaType());
 }
 
 void ImageFrame::setStatus(Status status)
 {
     m_status = status;
     if (m_status == FrameComplete) {
         m_bitmap.setAlphaType(computeAlphaType());
         // Send pending pixels changed notifications now, because we can't do this after
         // the bitmap has been marked immutable.
         notifyBitmapIfPixelsChanged();
-        m_bitmap.setImmutable(); // Tell the bitmap it's done.
     }
 }
 
 void ImageFrame::zeroFillFrameRect(const IntRect& rect)
 {
     if (rect.isEmpty())
         return;
 
     m_bitmap.eraseArea(rect, SkColorSetARGB(0, 0, 0, 0));
     setHasAlpha(true);
 }
 
 SkAlphaType ImageFrame::computeAlphaType() const
 {
     // If the frame is not fully loaded, there will be transparent pixels,
     // so we can't tell skia we're opaque, even for image types that logically
     // always are (e.g. jpeg).
     if (!m_hasAlpha && m_status == FrameComplete)
         return kOpaque_SkAlphaType;
 
     return m_premultiplyAlpha ? kPremul_SkAlphaType : kUnpremul_SkAlphaType;
 }
 
 } // namespace blink