gecko-dev/image/ClippedImage.h

/* -*- 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 http://mozilla.org/MPL/2.0/. */

#ifndef mozilla_image_ClippedImage_h
#define mozilla_image_ClippedImage_h

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

#include <utility>

namespace mozilla {
namespace image {

class ClippedImageCachedSurface;
class DrawSingleTileCallback;

/**
 * An Image wrapper that clips an image against a rectangle. Right now only
 * absolute coordinates in pixels are supported.
 *
 * XXX(seth): There a known (performance, not correctness) issue with
 * GetImageContainer. See the comments for that method for more information.
 */
class ClippedImage : public ImageWrapper {
  typedef gfx::SourceSurface SourceSurface;

 public:
  NS_INLINE_DECL_REFCOUNTING_INHERITED(ClippedImage, ImageWrapper)

  NS_IMETHOD GetWidth(int32_t* aWidth) override;
  NS_IMETHOD GetHeight(int32_t* aHeight) override;
  NS_IMETHOD GetIntrinsicSize(nsSize* aSize) override;
  Maybe<AspectRatio> GetIntrinsicRatio() override;
  NS_IMETHOD_(already_AddRefed<SourceSurface>)
  GetFrame(uint32_t aWhichFrame, uint32_t aFlags) override;
  NS_IMETHOD_(already_AddRefed<SourceSurface>)
  GetFrameAtSize(const gfx::IntSize& aSize, uint32_t aWhichFrame,
                 uint32_t aFlags) override;
  NS_IMETHOD_(bool)
  IsImageContainerAvailable(layers::LayerManager* aManager,
                            uint32_t aFlags) override;
  NS_IMETHOD_(already_AddRefed<layers::ImageContainer>)
  GetImageContainer(layers::LayerManager* aManager, uint32_t aFlags) override;
  NS_IMETHOD_(bool)
  IsImageContainerAvailableAtSize(layers::LayerManager* aManager,
                                  const gfx::IntSize& aSize,
                                  uint32_t aFlags) override;
  NS_IMETHOD_(ImgDrawResult)
  GetImageContainerAtSize(layers::LayerManager* aManager,
                          const gfx::IntSize& aSize,
                          const Maybe<SVGImageContext>& aSVGContext,
                          uint32_t aFlags,
                          layers::ImageContainer** aOutContainer) override;
  NS_IMETHOD_(ImgDrawResult)
  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 RequestDiscard() override;
  NS_IMETHOD_(Orientation) GetOrientation() override;
  NS_IMETHOD_(nsIntRect)
  GetImageSpaceInvalidationRect(const nsIntRect& aRect) override;
  nsIntSize OptimalImageSizeForDest(const gfxSize& aDest, uint32_t aWhichFrame,
                                    gfx::SamplingFilter aSamplingFilter,
                                    uint32_t aFlags) override;

 protected:
  ClippedImage(Image* aImage, nsIntRect aClip,
               const Maybe<nsSize>& aSVGViewportSize);

  virtual ~ClippedImage();

 private:
  std::pair<ImgDrawResult, RefPtr<SourceSurface>> GetFrameInternal(
      const nsIntSize& aSize, const Maybe<SVGImageContext>& aSVGContext,
      uint32_t aWhichFrame, uint32_t aFlags, float aOpacity);
  bool ShouldClip();
  ImgDrawResult DrawSingleTile(gfxContext* aContext, const nsIntSize& aSize,
                               const ImageRegion& aRegion, uint32_t aWhichFrame,
                               gfx::SamplingFilter aSamplingFilter,
                               const Maybe<SVGImageContext>& aSVGContext,
                               uint32_t aFlags, float aOpacity);

  // If we are forced to draw a temporary surface, we cache it here.
  UniquePtr<ClippedImageCachedSurface> mCachedSurface;

  nsIntRect mClip;                    // The region to clip to.
  Maybe<bool> mShouldClip;            // Memoized ShouldClip() if present.
  Maybe<nsIntSize> mSVGViewportSize;  // If we're clipping a VectorImage, this
                                      // is the size of viewport of that image.
  friend class DrawSingleTileCallback;
  friend class ImageOps;
};

}  // namespace image
}  // namespace mozilla

#endif  // mozilla_image_ClippedImage_h