tor-browser

ImageOps.h (5665B)

---

/* -*- 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_ImageOps_h
#define mozilla_image_ImageOps_h

#include "nsCOMPtr.h"
#include "nsRect.h"
#include "ImageMetadata.h"

class gfxDrawable;
class imgIContainer;
class nsIInputStream;

namespace mozilla {

namespace gfx {
class SourceSurface;
}

namespace image {

class Image;
struct Orientation;
class SourceBuffer;

class ImageOps {
public:
 class ImageBuffer {
  public:
   NS_INLINE_DECL_THREADSAFE_REFCOUNTING(ImageOps::ImageBuffer);

  protected:
   friend class ImageOps;

   ImageBuffer() = default;
   virtual ~ImageBuffer() = default;

   virtual already_AddRefed<SourceBuffer> GetSourceBuffer() const = 0;
 };

 /**
  * Creates a version of an existing image which does not animate and is frozen
  * at the first frame.
  *
  * @param aImage         The existing image.
  */
 static already_AddRefed<Image> Freeze(Image* aImage);
 static already_AddRefed<imgIContainer> Freeze(imgIContainer* aImage);

 /**
  * Creates a clipped version of an existing image. Animation is unaffected.
  *
  * @param aImage           The existing image.
  * @param aClip            The rectangle to clip the image against.
  * @param aSVGViewportSize The specific viewort size of aImage. Unless aImage
  *                         is a vector image without intrinsic size, this
  *                         argument should be pass as Nothing().
  */
 static already_AddRefed<Image> Clip(
     Image* aImage, nsIntRect aClip,
     const Maybe<nsSize>& aSVGViewportSize = Nothing());
 static already_AddRefed<imgIContainer> Clip(
     imgIContainer* aImage, nsIntRect aClip,
     const Maybe<nsSize>& aSVGViewportSize = Nothing());

 /**
  * Creates a version of an existing image which is rotated and/or flipped to
  * the specified orientation.
  *
  * @param aImage         The existing image.
  * @param aOrientation   The desired orientation.
  */
 static already_AddRefed<Image> Orient(Image* aImage,
                                       Orientation aOrientation);
 static already_AddRefed<imgIContainer> Orient(imgIContainer* aImage,
                                               Orientation aOrientation);

 /**
  * Creates a version of an existing image which undoes any rotation and/or
  * flipping that it has automatically handled.
  *
  * This only undoes the effect of a RasterImage's automatic orientation
  * handling.
  */
 static already_AddRefed<imgIContainer> Unorient(imgIContainer* aImage);

 /**
  * Creates an image from a gfxDrawable.
  *
  * @param aDrawable      The gfxDrawable.
  */
 static already_AddRefed<imgIContainer> CreateFromDrawable(
     gfxDrawable* aDrawable);

 /**
  * Create a buffer to be used with DecodeMetadata and DecodeToSurface. Reusing
  * an ImageBuffer representing the given input stream is more efficient if one
  * has multiple Decode* calls to make on that stream.
  *
  * @param aInputStream An input stream containing an encoded image. The
  * ownership is taken.
  * @return An image buffer derived from the input stream.
  */
 static already_AddRefed<ImageBuffer> CreateImageBuffer(
     already_AddRefed<nsIInputStream> aInputStream);

 /**
  * Decodes an image's metadata from an nsIInputStream into the given
  * structure. This function may be called off-main-thread.
  *
  * @param aInputStream An input stream containing an encoded image. Ownership
  * is taken.
  * @param aMimeType The MIME type of the image.
  * @param aMetadata Where the image metadata is stored upon success.
  * @return The status of the operation.
  */
 static nsresult DecodeMetadata(already_AddRefed<nsIInputStream> aInputStream,
                                const nsACString& aMimeType,
                                ImageMetadata& aMetadata);

 /**
  * Same as above but takes an ImageBuffer instead of nsIInputStream.
  */
 static nsresult DecodeMetadata(ImageBuffer* aBuffer,
                                const nsACString& aMimeType,
                                ImageMetadata& aMetadata);

 /**
  * Decodes an image from an nsIInputStream directly into a SourceSurface,
  * without ever creating an Image or imgIContainer (which are mostly
  * main-thread-only). That means that this function may be called
  * off-main-thread.
  *
  * @param aInputStream An input stream containing an encoded image. The
  * ownership is taken.
  * @param aMimeType The MIME type of the image.
  * @param aFlags Flags of the imgIContainer::FLAG_DECODE_* variety.
  * @return A SourceSurface containing the first frame of the image at its
  *         intrinsic size, or nullptr if the image cannot be decoded.
  */
 static already_AddRefed<gfx::SourceSurface> DecodeToSurface(
     already_AddRefed<nsIInputStream> aInputStream,
     const nsACString& aMimeType, uint32_t aFlags,
     const Maybe<gfx::IntSize>& aSize = Nothing());

 /**
  * Same as above but takes an ImageBuffer instead of nsIInputStream.
  */
 static already_AddRefed<gfx::SourceSurface> DecodeToSurface(
     ImageBuffer* aBuffer, const nsACString& aMimeType, uint32_t aFlags,
     const Maybe<gfx::IntSize>& aSize = Nothing());

private:
 class ImageBufferImpl;

 // This is a static utility class, so disallow instantiation.
 virtual ~ImageOps() = 0;
};

}  // namespace image
}  // namespace mozilla

#endif  // mozilla_image_ImageOps_h