The Tor Browser / file revision

 /*

  * Copyright 2012 Google Inc.

  *

  * Use of this source code is governed by a BSD-style license that can be

  * found in the LICENSE file.

  */

 #ifndef SkImage_DEFINED

 #define SkImage_DEFINED

 #include "SkImageInfo.h"

 #include "SkImageEncoder.h"

 #include "SkRefCnt.h"

 #include "SkScalar.h"

 class SkData;

 class SkCanvas;

 class SkPaint;

 class SkShader;

 class GrContext;

 class GrTexture;

 // need for TileMode

 #include "SkShader.h"

 /**

  *  SkImage is an abstraction for drawing a rectagle of pixels, though the

  *  particular type of image could be actually storing its data on the GPU, or

  *  as drawing commands (picture or PDF or otherwise), ready to be played back

  *  into another canvas.

  *

  *  The content of SkImage is always immutable, though the actual storage may

  *  change, if for example that image can be re-created via encoded data or

  *  other means.

  */

 class SK_API SkImage : public SkRefCnt {

 public:

     SK_DECLARE_INST_COUNT(SkImage)

     typedef SkImageInfo Info;

     static SkImage* NewRasterCopy(const Info&, const void* pixels, size_t rowBytes);

     static SkImage* NewRasterData(const Info&, SkData* pixels, size_t rowBytes);

     static SkImage* NewEncodedData(SkData*);

     /**

      * GrTexture is a more logical parameter for this factory, but its

      * interactions with scratch cache still has issues, so for now we take

      * SkBitmap instead. This will be changed in the future. skbug.com/1449

      */

     static SkImage* NewTexture(const SkBitmap&);

     int width() const { return fWidth; }

     int height() const { return fHeight; }

     uint32_t uniqueID() const { return fUniqueID; }

     /**

      * Return the GrTexture that stores the image pixels. Calling getTexture

      * does not affect the reference count of the GrTexture object.

      * Will return NULL if the image does not use a texture.

      */

     GrTexture* getTexture();

     SkShader*   newShaderClamp() const;

     SkShader*   newShader(SkShader::TileMode, SkShader::TileMode) const;

     void draw(SkCanvas*, SkScalar x, SkScalar y, const SkPaint*);

     /**

      *  Draw the image, cropped to the src rect, to the dst rect of a canvas.

      *  If src is larger than the bounds of the image, the rest of the image is

      *  filled with transparent black pixels.

      *

      *  See SkCanvas::drawBitmapRectToRect for similar behavior.

      */

     void draw(SkCanvas*, const SkRect* src, const SkRect& dst, const SkPaint*);

     /**

      *  If the image has direct access to its pixels (i.e. they are in local

      *  RAM) return the (const) address of those pixels, and if not null, return

      *  the ImageInfo and rowBytes. The returned address is only valid while

      *  the image object is in scope.

      *

      *  On failure, returns NULL and the info and rowBytes parameters are

      *  ignored.

      */

     const void* peekPixels(SkImageInfo* info, size_t* rowBytes) const;

     /**

      *  Encode the image's pixels and return the result as a new SkData, which

      *  the caller must manage (i.e. call unref() when they are done).

      *

      *  If the image type cannot be encoded, or the requested encoder type is

      *  not supported, this will return NULL.

      */

     SkData* encode(SkImageEncoder::Type t = SkImageEncoder::kPNG_Type,

                    int quality = 80) const;

 protected:

     SkImage(int width, int height) :

         fWidth(width),

         fHeight(height),

         fUniqueID(NextUniqueID()) {

         SkASSERT(width >= 0);

         SkASSERT(height >= 0);

     }

 private:

     const int       fWidth;

     const int       fHeight;

     const uint32_t  fUniqueID;

     static uint32_t NextUniqueID();

     typedef SkRefCnt INHERITED;

     /**

      *  Return a copy of the image's pixels, limiting them to the subset

      *  rectangle's intersection wit the image bounds. If subset is NULL, then

      *  the entire image will be considered.

      *

      *  If the bitmap's pixels have already been allocated, then readPixels()

      *  will succeed only if it can support converting the image's pixels into

      *  the bitmap's ColorType/AlphaType. Any pixels in the bitmap that do not

      *  intersect with the image's bounds and the subset (if not null) will be

      *  left untouched.

      *

      *  If the bitmap is initially empty/unallocated, then it will be allocated

      *  using the default allocator, and the ColorType/AlphaType will be chosen

      *  to most closely fit the image's configuration.

      *

      *  On failure, false will be returned, and bitmap will unmodified.

      */

     // On ice for now:

     // - should it respect the particular colortype/alphatype of the src

     // - should it have separate entrypoints for preallocated and not bitmaps?

     // - isn't it enough to allow the caller to draw() the image into a canvas?

     bool readPixels(SkBitmap* bitmap, const SkIRect* subset = NULL) const;

 };

 #endif