/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */

/* vim:set ts=2 sw=2 sts=2 et cindent: */

/* 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_dom_ImageBitmap_h

#define mozilla_dom_ImageBitmap_h

#include "mozilla/Attributes.h"

#include "mozilla/dom/ImageBitmapSource.h"

#include "mozilla/dom/TypedArray.h"

#include "mozilla/gfx/Rect.h"

#include "mozilla/Maybe.h"

#include "mozilla/UniquePtr.h"

#include "gfxTypes.h" // for gfxAlphaType

#include "nsCycleCollectionParticipant.h"

struct JSContext;

struct JSStructuredCloneReader;

struct JSStructuredCloneWriter;

class nsIGlobalObject;

namespace mozilla {

class ErrorResult;

namespace gfx {

class DataSourceSurface;

class DrawTarget;

class SourceSurface;

}

namespace layers {

class Image;

}

namespace dom {

class OffscreenCanvas;

class ArrayBufferViewOrArrayBuffer;

class CanvasRenderingContext2D;

struct ChannelPixelLayout;

class CreateImageBitmapFromBlob;

class CreateImageBitmapFromBlobTask;

class CreateImageBitmapFromBlobWorkerTask;

class File;

class HTMLCanvasElement;

class HTMLImageElement;

class HTMLVideoElement;

enum class ImageBitmapFormat : uint8_t;

class ImageData;

class ImageUtils;

template<typename T> class MapDataIntoBufferSource;

class Promise;

class PostMessageEvent; // For StructuredClone between windows.

class ImageBitmapShutdownObserver;

struct ImageBitmapCloneData final

{

  RefPtr<gfx::DataSourceSurface> mSurface;

  gfx::IntRect mPictureRect;

  gfxAlphaType mAlphaType;

  bool mIsCroppingAreaOutSideOfSourceImage;

};

/*

 * ImageBitmap is an opaque handler to several kinds of image-like objects from

 * HTMLImageElement, HTMLVideoElement, HTMLCanvasElement, ImageData to

 * CanvasRenderingContext2D and Image Blob.

 *

 * An ImageBitmap could be painted to a canvas element.

 *

 * Generally, an ImageBitmap only keeps a reference to its source object's

 * buffer, but if the source object is an ImageData, an Blob or a

 * HTMLCanvasElement with WebGL rendering context, the ImageBitmap copy the

 * source object's buffer.

 */

class ImageBitmap final : public nsISupports,

                          public nsWrapperCache

{

public:

  NS_DECL_CYCLE_COLLECTING_ISUPPORTS

  NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS(ImageBitmap)

  nsCOMPtr<nsIGlobalObject> GetParentObject() const { return mParent; }

  virtual JSObject* WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto) override;

  uint32_t Width() const

  {

    return mPictureRect.Width();

  }

  uint32_t Height() const

  {

    return mPictureRect.Height();

  }

  void Close();

  /*

   * The PrepareForDrawTarget() might return null if the mPictureRect does not

   * intersect with the size of mData.

   */

  already_AddRefed<gfx::SourceSurface>

  PrepareForDrawTarget(gfx::DrawTarget* aTarget);

  /*

   * Transfer ownership of buffer to caller. So this function call

   * Close() implicitly.

   */

  already_AddRefed<layers::Image>

  TransferAsImage();

  // This method returns null if the image has been already closed.

  UniquePtr<ImageBitmapCloneData>

  ToCloneData() const;

  static already_AddRefed<ImageBitmap>

  CreateFromCloneData(nsIGlobalObject* aGlobal, ImageBitmapCloneData* aData);

  static already_AddRefed<ImageBitmap>

  CreateFromOffscreenCanvas(nsIGlobalObject* aGlobal,

                            OffscreenCanvas& aOffscreenCanvas,

                            ErrorResult& aRv);

  static already_AddRefed<Promise>

  Create(nsIGlobalObject* aGlobal, const ImageBitmapSource& aSrc,

         const Maybe<gfx::IntRect>& aCropRect, ErrorResult& aRv);

  static already_AddRefed<Promise>

  Create(nsIGlobalObject* aGlobal,

         const ImageBitmapSource& aBuffer,

         int32_t aOffset, int32_t aLength,

         mozilla::dom::ImageBitmapFormat aFormat,

         const Sequence<mozilla::dom::ChannelPixelLayout>& aLayout,

         ErrorResult& aRv);

  static JSObject*

  ReadStructuredClone(JSContext* aCx,

                      JSStructuredCloneReader* aReader,

                      nsIGlobalObject* aParent,

                      const nsTArray<RefPtr<gfx::DataSourceSurface>>& aClonedSurfaces,

                      uint32_t aIndex);

  static bool

  WriteStructuredClone(JSStructuredCloneWriter* aWriter,

                       nsTArray<RefPtr<gfx::DataSourceSurface>>& aClonedSurfaces,

                       ImageBitmap* aImageBitmap);

  friend CreateImageBitmapFromBlob;

  friend CreateImageBitmapFromBlobTask;

  friend CreateImageBitmapFromBlobWorkerTask;

  template<typename T>

  friend class MapDataIntoBufferSource;

  // Mozilla Extensions

  ImageBitmapFormat

  FindOptimalFormat(const Optional<Sequence<ImageBitmapFormat>>& aPossibleFormats,

                    ErrorResult& aRv);

  int32_t

  MappedDataLength(ImageBitmapFormat aFormat, ErrorResult& aRv);

  already_AddRefed<Promise>

  MapDataInto(JSContext* aCx,

              ImageBitmapFormat aFormat,

              const ArrayBufferViewOrArrayBuffer& aBuffer,

              int32_t aOffset, ErrorResult& aRv);

  size_t GetAllocatedSize() const;

  void OnShutdown();

protected:

  /*

   * The default value of aIsPremultipliedAlpha is TRUE because that the

   * data stored in HTMLImageElement, HTMLVideoElement, HTMLCanvasElement,

   * CanvasRenderingContext2D are alpha-premultiplied in default.

   *

   * Actually, if one HTMLCanvasElement's rendering context is WebGLContext, it

   * is possible to get un-premultipliedAlpha data out. But, we do not do it in

   * the CreateInternal(from HTMLCanvasElement) method.

   *

   * It is also possible to decode an image which is encoded with alpha channel

   * to be non-premultipliedAlpha. This could be applied in

   * 1) the CreateInternal(from HTMLImageElement) method (which might trigger

   *    re-decoding if the original decoded data is alpha-premultiplied) and

   * 2) while decoding a blob. But we do not do it in both code path too.

   *

   * ImageData's underlying data is triggered as non-premultipliedAlpha, so set

   * the aIsPremultipliedAlpha to be false in the

   * CreateInternal(from ImageData) method.

   */

  ImageBitmap(nsIGlobalObject* aGlobal, layers::Image* aData,

              gfxAlphaType aAlphaType = gfxAlphaType::Premult);

  virtual ~ImageBitmap();

  void SetPictureRect(const gfx::IntRect& aRect, ErrorResult& aRv);

  void SetIsCroppingAreaOutSideOfSourceImage(const gfx::IntSize& aSourceSize,

                                             const Maybe<gfx::IntRect>& aCroppingRect);

  static already_AddRefed<ImageBitmap>

  CreateInternal(nsIGlobalObject* aGlobal, HTMLImageElement& aImageEl,

                 const Maybe<gfx::IntRect>& aCropRect, ErrorResult& aRv);

  static already_AddRefed<ImageBitmap>

  CreateInternal(nsIGlobalObject* aGlobal, HTMLVideoElement& aVideoEl,

                 const Maybe<gfx::IntRect>& aCropRect, ErrorResult& aRv);

  static already_AddRefed<ImageBitmap>

  CreateInternal(nsIGlobalObject* aGlobal, HTMLCanvasElement& aCanvasEl,

                 const Maybe<gfx::IntRect>& aCropRect, ErrorResult& aRv);

  static already_AddRefed<ImageBitmap>

  CreateInternal(nsIGlobalObject* aGlobal, ImageData& aImageData,

                 const Maybe<gfx::IntRect>& aCropRect, ErrorResult& aRv);

  static already_AddRefed<ImageBitmap>

  CreateInternal(nsIGlobalObject* aGlobal, CanvasRenderingContext2D& aCanvasCtx,

                 const Maybe<gfx::IntRect>& aCropRect, ErrorResult& aRv);

  static already_AddRefed<ImageBitmap>

  CreateInternal(nsIGlobalObject* aGlobal, ImageBitmap& aImageBitmap,

                 const Maybe<gfx::IntRect>& aCropRect, ErrorResult& aRv);

  nsCOMPtr<nsIGlobalObject> mParent;

  /*

   * The mData is the data buffer of an ImageBitmap, so the mData must not be

   * null.

   *

   * The mSurface is a cache for drawing the ImageBitmap onto a

   * HTMLCanvasElement. The mSurface is null while the ImageBitmap is created

   * and then will be initialized while the PrepareForDrawTarget() method is

   * called first time.

   *

   * The mSurface might just be a reference to the same data buffer of the mData

   * if the are of mPictureRect is just the same as the mData's size. Or, it is

   * a independent data buffer which is copied and cropped form the mData's data

   * buffer.

   */

  RefPtr<layers::Image> mData;

  RefPtr<gfx::SourceSurface> mSurface;

  /*

   * This is used in the ImageBitmap-Extensions implementation.

   * ImageUtils is a wrapper to layers::Image, which add some common methods for

   * accessing the layers::Image's data.

   */

  UniquePtr<ImageUtils> mDataWrapper;

  /*

   * The mPictureRect is the size of the source image in default, however, if

   * users specify the cropping area while creating an ImageBitmap, then this

   * mPictureRect is the cropping area.

   *

   * Note that if the CreateInternal() copies and crops data from the source

   * image, then this mPictureRect is just the size of the final mData.

   *

   * The mPictureRect will be used at PrepareForDrawTarget() while user is going

   * to draw this ImageBitmap into a HTMLCanvasElement.

   */

  gfx::IntRect mPictureRect;

  const gfxAlphaType mAlphaType;

  RefPtr<ImageBitmapShutdownObserver> mShutdownObserver;

  /*

   * Set mIsCroppingAreaOutSideOfSourceImage if image bitmap was cropped to the

   * source rectangle so that it contains any transparent black pixels (cropping

   * area is outside of the source image).

   * This is used in mapDataInto() to check if we should reject promise with

   * IndexSizeError.

   */

  bool mIsCroppingAreaOutSideOfSourceImage;

  /*

   * Whether this object allocated allocated and owns the image data.

   */

  bool mAllocatedImageData;

};

} // namespace dom

} // namespace mozilla

#endif // mozilla_dom_ImageBitmap_h