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      1 /*
      2  * Copyright (C) 2006, 2007, 2008 Apple Computer, Inc.  All rights reserved.
      3  * Copyright (C) 2007 Alp Toker <alp (at) atoker.com>
      4  *
      5  * Redistribution and use in source and binary forms, with or without
      6  * modification, are permitted provided that the following conditions
      7  * are met:
      8  * 1. Redistributions of source code must retain the above copyright
      9  *    notice, this list of conditions and the following disclaimer.
     10  * 2. Redistributions in binary form must reproduce the above copyright
     11  *    notice, this list of conditions and the following disclaimer in the
     12  *    documentation and/or other materials provided with the distribution.
     13  *
     14  * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
     15  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     17  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
     18  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
     19  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
     20  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
     21  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
     22  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     24  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     25  */
     26 
     27 #ifndef CanvasImageSource_h
     28 #define CanvasImageSource_h
     29 
     30 #include "wtf/PassRefPtr.h"
     31 
     32 namespace blink {
     33 
     34 class Image;
     35 class SecurityOrigin;
     36 
     37 enum SourceImageMode {
     38     CopySourceImageIfVolatile,
     39     DontCopySourceImage
     40 };
     41 
     42 enum SourceImageStatus {
     43     NormalSourceImageStatus,
     44     ExternalSourceImageStatus, // Shared with another GPU context
     45     UndecodableSourceImageStatus, // Image element with a 'broken' image
     46     ZeroSizeCanvasSourceImageStatus, // Source is a canvas with width or heigh of zero
     47     IncompleteSourceImageStatus, // Image element with no source media
     48     InvalidSourceImageStatus,
     49 };
     50 
     51 class CanvasImageSource {
     52 public:
     53     virtual PassRefPtr<Image> getSourceImageForCanvas(SourceImageMode, SourceImageStatus* = 0) const = 0;
     54 
     55     // IMPORTANT: Result must be independent of whether destinationContext is
     56     // already tainted because this function may be used to determine whether
     57     // a CanvasPattern is "origin clean", and that pattern may be used on
     58     // another canvas, which may not be already tainted.
     59     virtual bool wouldTaintOrigin(SecurityOrigin* destinationSecurityOrigin) const = 0;
     60 
     61     virtual bool isVideoElement() const { return false; }
     62 
     63     // Adjusts the source and destination rectangles for cases where the actual
     64     // source image is a subregion of the image returned by getSourceImageForCanvas.
     65     virtual void adjustDrawRects(FloatRect* srcRect, FloatRect* dstRect) const { }
     66 
     67     virtual FloatSize sourceSize() const = 0;
     68     virtual FloatSize defaultDestinationSize() const { return sourceSize(); }
     69     virtual const KURL& sourceURL() const { return blankURL(); }
     70 
     71 protected:
     72     virtual ~CanvasImageSource() { }
     73 };
     74 
     75 } // namespace blink
     76 
     77 #endif
     78