dom/canvas/ImageBitmapRenderingContext.h

   1 /* This Source Code Form is subject to the terms of the Mozilla Public
   2  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
   3  * You can obtain one at http://mozilla.org/MPL/2.0/. */
   4
   5 #ifndef ImageBitmapRenderingContext_h
   6 #define ImageBitmapRenderingContext_h
   7
   8 #include "mozilla/dom/ImageBitmap.h"
   9 #include "mozilla/gfx/2D.h"
  10 #include "mozilla/gfx/DataSurfaceHelpers.h"
  11 #include "mozilla/gfx/Point.h"
  12 #include "mozilla/layers/WebRenderUserData.h"
  13 #include "imgIEncoder.h"
  14 #include "ImageEncoder.h"
  15 #include "nsICanvasRenderingContextInternal.h"
  16 #include "nsWrapperCache.h"
  17
  18 namespace mozilla {
  19
  20 namespace gfx {
  21 class DataSourceSurface;
  22 class DrawTarget;
  23 class SourceSurface;
  24 }  // namespace gfx
  25
  26 namespace layers {
  27 class Image;
  28 class ImageContainer;
  29 }  // namespace layers
  30
  31 namespace dom {
  32
  33 /**
  34  * The purpose of ImageBitmapRenderingContext is to provide a faster and
  35  * efficient way to display ImageBitmap. Simply call TransferFromImageBitmap()
  36  * then we'll transfer the surface of ImageBitmap to this context and then to
  37  * use it to display.
  38  *
  39  * See more details in spec: https://wiki.whatwg.org/wiki/OffscreenCanvas
  40  */
  41 class ImageBitmapRenderingContext final
  42     : public nsICanvasRenderingContextInternal,
  43       public nsWrapperCache {
  44   virtual ~ImageBitmapRenderingContext();
  45
  46  public:
  47   ImageBitmapRenderingContext();
  48
  49   virtual JSObject* WrapObject(JSContext* aCx,
  50                                JS::Handle<JSObject*> aGivenProto) override;
  51
  52   // nsISupports interface + CC
  53   NS_DECL_CYCLE_COLLECTING_ISUPPORTS
  54
  55   NS_DECL_CYCLE_COLLECTION_WRAPPERCACHE_CLASS(ImageBitmapRenderingContext)
  56
  57   void GetCanvas(
  58       Nullable<OwningHTMLCanvasElementOrOffscreenCanvas>& retval) const;
  59
  60   void TransferImageBitmap(ImageBitmap& aImageBitmap, ErrorResult& aRv);
  61   void TransferFromImageBitmap(ImageBitmap* aImageBitmap, ErrorResult& aRv);
  62
  63   // nsICanvasRenderingContextInternal
  64   virtual int32_t GetWidth() override { return mWidth; }
  65   virtual int32_t GetHeight() override { return mHeight; }
  66
  67   NS_IMETHOD SetDimensions(int32_t aWidth, int32_t aHeight) override;
  68
  69   NS_IMETHOD InitializeWithDrawTarget(
  70       nsIDocShell* aDocShell, NotNull<gfx::DrawTarget*> aTarget) override;
  71
  72   virtual mozilla::UniquePtr<uint8_t[]> GetImageBuffer(
  73       int32_t* out_format, gfx::IntSize* out_imageSize) override;
  74   NS_IMETHOD GetInputStream(const char* aMimeType,
  75                             const nsAString& aEncoderOptions,
  76                             nsIInputStream** aStream) override;
  77
  78   virtual already_AddRefed<mozilla::gfx::SourceSurface> GetSurfaceSnapshot(
  79       gfxAlphaType* aOutAlphaType) override;
  80
  81   virtual void SetOpaqueValueFromOpaqueAttr(bool aOpaqueAttrValue) override;
  82   virtual bool GetIsOpaque() override;
  83   void ResetBitmap() override;
  84   virtual already_AddRefed<layers::Image> GetAsImage() override {
  85     return ClipToIntrinsicSize();
  86   }
  87   bool UpdateWebRenderCanvasData(nsDisplayListBuilder* aBuilder,
  88                                  WebRenderCanvasData* aCanvasData) override;
  89   virtual void MarkContextClean() override;
  90
  91   NS_IMETHOD Redraw(const gfxRect& aDirty) override;
  92
  93   virtual void DidRefresh() override;
  94
  95   void MarkContextCleanForFrameCapture() override {
  96     mFrameCaptureState = FrameCaptureState::CLEAN;
  97   }
  98   Watchable<FrameCaptureState>* GetFrameCaptureState() override {
  99     return &mFrameCaptureState;
 100   }
 101
 102  protected:
 103   already_AddRefed<gfx::DataSourceSurface> MatchWithIntrinsicSize();
 104   already_AddRefed<layers::Image> ClipToIntrinsicSize();
 105   int32_t mWidth;
 106   int32_t mHeight;
 107
 108   RefPtr<layers::Image> mImage;
 109
 110   /**
 111    * Flag to avoid unnecessary surface copies to FrameCaptureListeners in the
 112    * case when the canvas is not currently being drawn into and not rendered
 113    * but canvas capturing is still ongoing.
 114    */
 115   Watchable<FrameCaptureState> mFrameCaptureState;
 116 };
 117
 118 }  // namespace dom
 119 }  // namespace mozilla
 120
 121 #endif /* ImageBitmapRenderingContext_h */