dom/canvas/nsICanvasRenderingContextInternal.h

   1 /* -*- Mode: C++; tab-width: 40; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6 #ifndef nsICanvasRenderingContextInternal_h___
   7 #define nsICanvasRenderingContextInternal_h___
   8
   9 #include "mozilla/gfx/2D.h"
  10 #include "nsISupports.h"
  11 #include "nsIInputStream.h"
  12 #include "nsIDocShell.h"
  13 #include "nsRefreshDriver.h"
  14 #include "mozilla/dom/HTMLCanvasElement.h"
  15 #include "GraphicsFilter.h"
  16 #include "mozilla/RefPtr.h"
  17
  18 #define NS_ICANVASRENDERINGCONTEXTINTERNAL_IID \
  19 { 0x3cc9e801, 0x1806, 0x4ff6, \
  20   { 0x86, 0x14, 0xf9, 0xd0, 0xf4, 0xfb, 0x3b, 0x08 } }
  21
  22 class gfxContext;
  23 class gfxASurface;
  24 class nsDisplayListBuilder;
  25
  26 namespace mozilla {
  27 namespace layers {
  28 class CanvasLayer;
  29 class LayerManager;
  30 }
  31 namespace gfx {
  32 class SourceSurface;
  33 }
  34 }
  35
  36 class nsICanvasRenderingContextInternal :
  37   public nsISupports,
  38   public nsAPostRefreshObserver
  39 {
  40 public:
  41   typedef mozilla::layers::CanvasLayer CanvasLayer;
  42   typedef mozilla::layers::LayerManager LayerManager;
  43
  44   NS_DECLARE_STATIC_IID_ACCESSOR(NS_ICANVASRENDERINGCONTEXTINTERNAL_IID)
  45
  46   void SetCanvasElement(mozilla::dom::HTMLCanvasElement* aParentCanvas)
  47   {
  48     RemovePostRefreshObserver();
  49     mCanvasElement = aParentCanvas;
  50     AddPostRefreshObserverIfNecessary();
  51   }
  52
  53   virtual nsIPresShell *GetPresShell() {
  54     if (mCanvasElement) {
  55       return mCanvasElement->OwnerDoc()->GetShell();
  56     }
  57     return nullptr;
  58   }
  59
  60   void RemovePostRefreshObserver()
  61   {
  62     if (mRefreshDriver) {
  63       mRefreshDriver->RemovePostRefreshObserver(this);
  64       mRefreshDriver = nullptr;
  65     }
  66   }
  67
  68   void AddPostRefreshObserverIfNecessary()
  69   {
  70     if (!GetPresShell() ||
  71         !GetPresShell()->GetPresContext() ||
  72         !GetPresShell()->GetPresContext()->RefreshDriver()) {
  73       return;
  74     }
  75     mRefreshDriver = GetPresShell()->GetPresContext()->RefreshDriver();
  76     mRefreshDriver->AddPostRefreshObserver(this);
  77   }
  78
  79   mozilla::dom::HTMLCanvasElement* GetParentObject() const
  80   {
  81     return mCanvasElement;
  82   }
  83
  84 #ifdef DEBUG
  85     // Useful for testing
  86     virtual int32_t GetWidth() const = 0;
  87     virtual int32_t GetHeight() const = 0;
  88 #endif
  89
  90   // Sets the dimensions of the canvas, in pixels.  Called
  91   // whenever the size of the element changes.
  92   NS_IMETHOD SetDimensions(int32_t width, int32_t height) = 0;
  93
  94   NS_IMETHOD InitializeWithSurface(nsIDocShell *docShell, gfxASurface *surface, int32_t width, int32_t height) = 0;
  95
  96   // Creates an image buffer. Returns null on failure.
  97   virtual void GetImageBuffer(uint8_t** aImageBuffer, int32_t* aFormat) = 0;
  98
  99   // Gives you a stream containing the image represented by this context.
 100   // The format is given in aMimeTime, for example "image/png".
 101   //
 102   // If the image format does not support transparency or aIncludeTransparency
 103   // is false, alpha will be discarded and the result will be the image
 104   // composited on black.
 105   NS_IMETHOD GetInputStream(const char *aMimeType,
 106                             const char16_t *aEncoderOptions,
 107                             nsIInputStream **aStream) = 0;
 108
 109   // This gets an Azure SourceSurface for the canvas, this will be a snapshot
 110   // of the canvas at the time it was called.
 111   // If aPremultAlpha is provided, then it assumed the callee can handle
 112   // un-premultiplied surfaces, and *aPremultAlpha will be set to false
 113   // if one is returned.
 114   virtual mozilla::TemporaryRef<mozilla::gfx::SourceSurface> GetSurfaceSnapshot(bool* aPremultAlpha = nullptr) = 0;
 115
 116   // If this context is opaque, the backing store of the canvas should
 117   // be created as opaque; all compositing operators should assume the
 118   // dst alpha is always 1.0.  If this is never called, the context
 119   // defaults to false (not opaque).
 120   NS_IMETHOD SetIsOpaque(bool isOpaque) = 0;
 121   virtual bool GetIsOpaque() = 0;
 122
 123   // Invalidate this context and release any held resources, in preperation
 124   // for possibly reinitializing with SetDimensions/InitializeWithSurface.
 125   NS_IMETHOD Reset() = 0;
 126
 127   // Return the CanvasLayer for this context, creating
 128   // one for the given layer manager if not available.
 129   virtual already_AddRefed<CanvasLayer> GetCanvasLayer(nsDisplayListBuilder* aBuilder,
 130                                                        CanvasLayer *aOldLayer,
 131                                                        LayerManager *aManager) = 0;
 132
 133   // Return true if the canvas should be forced to be "inactive" to ensure
 134   // it can be drawn to the screen even if it's too large to be blitted by
 135   // an accelerated CanvasLayer.
 136   virtual bool ShouldForceInactiveLayer(LayerManager *aManager) { return false; }
 137
 138   virtual void MarkContextClean() = 0;
 139
 140   // Redraw the dirty rectangle of this canvas.
 141   NS_IMETHOD Redraw(const gfxRect &dirty) = 0;
 142
 143   NS_IMETHOD SetContextOptions(JSContext* aCx, JS::Handle<JS::Value> aOptions) { return NS_OK; }
 144
 145   // return true and fills in the bounding rect if elementis a child and has a hit region.
 146   virtual bool GetHitRegionRect(mozilla::dom::Element* aElement, nsRect& aRect) { return false; }
 147
 148   // Given a point, return hit region ID if it exists or an empty string if it doesn't
 149   virtual nsString GetHitRegion(const mozilla::gfx::Point& aPoint) { return nsString(); }
 150
 151   //
 152   // shmem support
 153   //
 154
 155   // If this context can be set to use Mozilla's Shmem segments as its backing
 156   // store, this will set it to that state. Note that if you have drawn
 157   // anything into this canvas before changing the shmem state, it will be
 158   // lost.
 159   NS_IMETHOD SetIsIPC(bool isIPC) = 0;
 160
 161 protected:
 162   nsRefPtr<mozilla::dom::HTMLCanvasElement> mCanvasElement;
 163   nsRefPtr<nsRefreshDriver> mRefreshDriver;
 164 };
 165
 166 NS_DEFINE_STATIC_IID_ACCESSOR(nsICanvasRenderingContextInternal,
 167                               NS_ICANVASRENDERINGCONTEXTINTERNAL_IID)
 168
 169 #endif /* nsICanvasRenderingContextInternal_h___ */