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_SCRIPT_HOLDER_CLASS(ImageBitmapRenderingContext)
  56
  57   void TransferImageBitmap(ImageBitmap& aImageBitmap);
  58   void TransferFromImageBitmap(ImageBitmap& aImageBitmap);
  59
  60   // nsICanvasRenderingContextInternal
  61   virtual int32_t GetWidth() override { return mWidth; }
  62   virtual int32_t GetHeight() override { return mHeight; }
  63
  64   NS_IMETHOD SetDimensions(int32_t aWidth, int32_t aHeight) override;
  65
  66   NS_IMETHOD InitializeWithDrawTarget(
  67       nsIDocShell* aDocShell, NotNull<gfx::DrawTarget*> aTarget) override;
  68
  69   virtual mozilla::UniquePtr<uint8_t[]> GetImageBuffer(
  70       int32_t* aFormat) override;
  71   NS_IMETHOD GetInputStream(const char* aMimeType,
  72                             const nsAString& aEncoderOptions,
  73                             nsIInputStream** aStream) override;
  74
  75   virtual already_AddRefed<mozilla::gfx::SourceSurface> GetSurfaceSnapshot(
  76       gfxAlphaType* aOutAlphaType) override;
  77
  78   virtual void SetOpaqueValueFromOpaqueAttr(bool aOpaqueAttrValue) override;
  79   virtual bool GetIsOpaque() override;
  80   NS_IMETHOD Reset() override;
  81   virtual already_AddRefed<Layer> GetCanvasLayer(
  82       nsDisplayListBuilder* aBuilder, Layer* aOldLayer,
  83       LayerManager* aManager) override;
  84   bool UpdateWebRenderCanvasData(nsDisplayListBuilder* aBuilder,
  85                                  WebRenderCanvasData* aCanvasData) override;
  86   virtual void MarkContextClean() override;
  87
  88   NS_IMETHOD Redraw(const gfxRect& aDirty) override;
  89   NS_IMETHOD SetIsIPC(bool aIsIPC) override;
  90
  91   virtual void DidRefresh() override;
  92
  93   virtual void MarkContextCleanForFrameCapture() override;
  94   virtual bool IsContextCleanForFrameCapture() override;
  95
  96  protected:
  97   already_AddRefed<gfx::DataSourceSurface> MatchWithIntrinsicSize();
  98   already_AddRefed<layers::Image> ClipToIntrinsicSize();
  99   int32_t mWidth;
 100   int32_t mHeight;
 101
 102   RefPtr<layers::Image> mImage;
 103
 104   /**
 105    * Flag to avoid unnecessary surface copies to FrameCaptureListeners in the
 106    * case when the canvas is not currently being drawn into and not rendered
 107    * but canvas capturing is still ongoing.
 108    */
 109   bool mIsCapturedFrameInvalid;
 110 };
 111
 112 }  // namespace dom
 113 }  // namespace mozilla
 114
 115 #endif /* ImageBitmapRenderingContext_h */