author Andrew Osmond <>
Tue, 21 May 2019 13:34:14 -0400
changeset 536431 3e3ebfd849558d6011dec7b53ea5942ba1da8867
parent 508163 6f3709b3878117466168c40affa7bca0b60cf75b
permissions -rw-r--r--
Bug 1550523 - Ensure that decoding methods for frozen images request the correct frame. r=tnikkel a=jcristau With WebRender, we had observed that the print preview for animated images was not displaying correctly. It should display the first frame but it was showing nothing the first time the preview was opened. Once the decoded image was available in the cache, it would display correctly if the preview was reloaded. The StartDecoding and RequestDecode variants always requested FRAME_CURRENT for animated images. They should use FRAME_FIRST for static requests / FrozenImage. Correcting this fixes the print preview. Differential Revision:

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at */

#ifndef mozilla_image_FrozenImage_h
#define mozilla_image_FrozenImage_h

#include "ImageWrapper.h"
#include "mozilla/gfx/2D.h"
#include "mozilla/RefPtr.h"

namespace mozilla {
namespace image {

 * An Image wrapper that disables animation, freezing the image at its first
 * frame. It does this using two strategies. If this is the only instance of the
 * image, animation will never start, because IncrementAnimationConsumers is
 * ignored. If there is another instance that is animated, that's still OK,
 * because any imgIContainer method that is affected by animation gets its
 * aWhichFrame argument set to FRAME_FIRST when it passes through FrozenImage.
 * XXX(seth): There a known (performance, not correctness) issue with
 * GetImageContainer. See the comments for that method for more information.
class FrozenImage : public ImageWrapper {
  typedef gfx::SourceSurface SourceSurface;


  virtual void IncrementAnimationConsumers() override;
  virtual void DecrementAnimationConsumers() override;

  NS_IMETHOD GetAnimated(bool* aAnimated) override;
  GetFrame(uint32_t aWhichFrame, uint32_t aFlags) override;
  GetFrameAtSize(const gfx::IntSize& aSize, uint32_t aWhichFrame,
                 uint32_t aFlags) override;
  IsImageContainerAvailable(layers::LayerManager* aManager,
                            uint32_t aFlags) override;
  GetImageContainer(layers::LayerManager* aManager, uint32_t aFlags) override;
  IsImageContainerAvailableAtSize(layers::LayerManager* aManager,
                                  const gfx::IntSize& aSize,
                                  uint32_t aFlags) override;
  GetImageContainerAtSize(layers::LayerManager* aManager,
                          const gfx::IntSize& aSize,
                          const Maybe<SVGImageContext>& aSVGContext,
                          uint32_t aFlags,
                          layers::ImageContainer** aOutContainer) override;
  Draw(gfxContext* aContext, const nsIntSize& aSize, const ImageRegion& aRegion,
       uint32_t aWhichFrame, gfx::SamplingFilter aSamplingFilter,
       const Maybe<SVGImageContext>& aSVGContext, uint32_t aFlags,
       float aOpacity) override;
  NS_IMETHOD StartDecoding(uint32_t aFlags, uint32_t aWhichFrame) override;
  StartDecodingWithResult(uint32_t aFlags, uint32_t aWhichFrame) override;
  RequestDecodeWithResult(uint32_t aFlags, uint32_t aWhichFrame) override;
  NS_IMETHOD RequestDecodeForSize(const nsIntSize& aSize, uint32_t aFlags,
                                  uint32_t aWhichFrame) override;
  NS_IMETHOD_(void) RequestRefresh(const TimeStamp& aTime) override;
  NS_IMETHOD GetAnimationMode(uint16_t* aAnimationMode) override;
  NS_IMETHOD SetAnimationMode(uint16_t aAnimationMode) override;
  NS_IMETHOD ResetAnimation() override;
  NS_IMETHOD_(float) GetFrameIndex(uint32_t aWhichFrame) override;

  explicit FrozenImage(Image* aImage) : ImageWrapper(aImage) {}
  virtual ~FrozenImage() {}

  friend class ImageOps;

}  // namespace image
}  // namespace mozilla

#endif  // mozilla_image_FrozenImage_h