gecko/content/canvas/public/nsICanvasRenderingContextInternal.h

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 * The Original Code is mozilla.org code.
 *
 * The Initial Developer of the Original Code is
 *   Vladimir Vukicevic <vladimir@pobox.com>
 * Portions created by the Initial Developer are Copyright (C) 2005
 * the Initial Developer. All Rights Reserved.
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 *
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#ifndef nsICanvasRenderingContextInternal_h___
#define nsICanvasRenderingContextInternal_h___

#include "nsISupports.h"
#include "nsICanvasElement.h"
#include "nsIInputStream.h"
#include "nsIDocShell.h"
#include "gfxPattern.h"

// {ed741c16-4039-469b-91da-dca742c51a9f}
#define NS_ICANVASRENDERINGCONTEXTINTERNAL_IID \
  { 0xed741c16, 0x4039, 0x469b, { 0x91, 0xda, 0xdc, 0xa7, 0x42, 0xc5, 0x1a, 0x9f } }

class gfxContext;
class gfxASurface;

class nsICanvasRenderingContextInternal : public nsISupports {
public:
  NS_DECLARE_STATIC_IID_ACCESSOR(NS_ICANVASRENDERINGCONTEXTINTERNAL_IID)

  // This method should NOT hold a ref to aParentCanvas; it will be called
  // with nsnull when the element is going away.
  NS_IMETHOD SetCanvasElement(nsICanvasElement* aParentCanvas) = 0;

  // Sets the dimensions of the canvas, in pixels.  Called
  // whenever the size of the element changes.
  NS_IMETHOD SetDimensions(PRInt32 width, PRInt32 height) = 0;

  NS_IMETHOD InitializeWithSurface(nsIDocShell *docShell, gfxASurface *surface, PRInt32 width, PRInt32 height) = 0;

  // Render the canvas at the origin of the given gfxContext
  NS_IMETHOD Render(gfxContext *ctx, gfxPattern::GraphicsFilter aFilter) = 0;

  // Gives you a stream containing the image represented by this context.
  // The format is given in aMimeTime, for example "image/png".
  //
  // If the image format does not support transparency or aIncludeTransparency
  // is false, alpha will be discarded and the result will be the image
  // composited on black.
  NS_IMETHOD GetInputStream(const char *aMimeType,
                            const PRUnichar *aEncoderOptions,
                            nsIInputStream **aStream) = 0;

  // If this canvas context can be represented with a simple Thebes surface,
  // return the surface.  Otherwise returns an error.
  NS_IMETHOD GetThebesSurface(gfxASurface **surface) = 0;

  // If this context is opaque, the backing store of the canvas should
  // be created as opaque; all compositing operators should assume the
  // dst alpha is always 1.0.  If this is never called, the context
  // defaults to false (not opaque).
  NS_IMETHOD SetIsOpaque(PRBool isOpaque) = 0;
};

NS_DEFINE_STATIC_IID_ACCESSOR(nsICanvasRenderingContextInternal,
                              NS_ICANVASRENDERINGCONTEXTINTERNAL_IID)

#endif /* nsICanvasRenderingContextInternal_h___ */