1 files changed, 167 insertions, 0 deletions
diff --git a/image/ImageOps.h b/image/ImageOps.h
new file mode 100644
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+++ b/image/ImageOps.h
@@ -0,0 +1,167 @@
+/* -*- 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