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 "nsICanvasRenderingContextInternal.h"
   9 #include "nsWrapperCache.h"
  10
  11 namespace mozilla {
  12
  13 namespace gfx {
  14 class DataSourceSurface;
  15 class DrawTarget;
  16 class SourceSurface;
  17 }  // namespace gfx
  18
  19 namespace layers {
  20 class Image;
  21 class ImageContainer;
  22 }  // namespace layers
  23
  24 namespace dom {
  25
  26 /**
  27  * The purpose of ImageBitmapRenderingContext is to provide a faster and
  28  * efficient way to display ImageBitmap. Simply call TransferFromImageBitmap()
  29  * then we'll transfer the surface of ImageBitmap to this context and then to
  30  * use it to display.
  31  *
  32  * See more details in spec: https://wiki.whatwg.org/wiki/OffscreenCanvas
  33  */
  34 class ImageBitmapRenderingContext final
  35     : public nsICanvasRenderingContextInternal,
  36       public nsWrapperCache {
  37   virtual ~ImageBitmapRenderingContext();
  38
  39  public:
  40   ImageBitmapRenderingContext();
  41
  42   virtual JSObject* WrapObject(JSContext* aCx,
  43                                JS::Handle<JSObject*> aGivenProto) override;
  44
  45   // nsISupports interface + CC
  46   NS_DECL_CYCLE_COLLECTING_ISUPPORTS
  47
  48   NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS(ImageBitmapRenderingContext)
  49
  50   void TransferImageBitmap(ImageBitmap& aImageBitmap);
  51   void TransferFromImageBitmap(ImageBitmap& aImageBitmap);
  52
  53   // nsICanvasRenderingContextInternal
  54   virtual int32_t GetWidth() override { return mWidth; }
  55   virtual int32_t GetHeight() override { return mHeight; }
  56
  57   NS_IMETHOD SetDimensions(int32_t aWidth, int32_t aHeight) override;
  58
  59   NS_IMETHOD InitializeWithDrawTarget(
  60       nsIDocShell* aDocShell, NotNull<gfx::DrawTarget*> aTarget) override;
  61
  62   virtual mozilla::UniquePtr<uint8_t[]> GetImageBuffer(
  63       int32_t* aFormat) override;
  64   NS_IMETHOD GetInputStream(const char* aMimeType,
  65                             const nsAString& aEncoderOptions,
  66                             nsIInputStream** aStream) override;
  67
  68   virtual already_AddRefed<mozilla::gfx::SourceSurface> GetSurfaceSnapshot(
  69       gfxAlphaType* aOutAlphaType) override;
  70
  71   virtual void SetOpaqueValueFromOpaqueAttr(bool aOpaqueAttrValue) override;
  72   virtual bool GetIsOpaque() override;
  73   NS_IMETHOD Reset() override;
  74   virtual already_AddRefed<Layer> GetCanvasLayer(
  75       nsDisplayListBuilder* aBuilder, Layer* aOldLayer,
  76       LayerManager* aManager) override;
  77   bool UpdateWebRenderCanvasData(nsDisplayListBuilder* aBuilder,
  78                                  WebRenderCanvasData* aCanvasData) override;
  79   virtual void MarkContextClean() override;
  80
  81   NS_IMETHOD Redraw(const gfxRect& aDirty) override;
  82   NS_IMETHOD SetIsIPC(bool aIsIPC) override;
  83
  84   virtual void DidRefresh() override;
  85
  86   virtual void MarkContextCleanForFrameCapture() override;
  87   virtual bool IsContextCleanForFrameCapture() override;
  88
  89  protected:
  90   already_AddRefed<gfx::DataSourceSurface> MatchWithIntrinsicSize();
  91   already_AddRefed<layers::Image> ClipToIntrinsicSize();
  92   int32_t mWidth;
  93   int32_t mHeight;
  94
  95   RefPtr<layers::Image> mImage;
  96
  97   /**
  98    * Flag to avoid unnecessary surface copies to FrameCaptureListeners in the
  99    * case when the canvas is not currently being drawn into and not rendered
 100    * but canvas capturing is still ongoing.
 101    */
 102   bool mIsCapturedFrameInvalid;
 103 };
 104
 105 }  // namespace dom
 106 }  // namespace mozilla
 107
 108 #endif /* ImageBitmapRenderingContext_h */