/*
* 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 "SkFilterQuality.h"
#include "SkImageInfo.h"
#include "SkImageEncoder.h"
#include "SkRefCnt.h"
#include "SkScalar.h"
#include "SkShader.h"
class SkData;
class SkCanvas;
class SkImageGenerator;
class SkPaint;
class SkString;
class SkSurface;
class SkSurfaceProps;
class GrContext;
class GrTexture;
/**
* 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.
*
* SkImage always has a non-zero dimensions. If there is a request to create a new image, either
* directly or via SkSurface, and either of the requested dimensions are zero, then NULL will be
* returned.
*/
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);
/**
* Construct a new SkImage based on the given ImageGenerator.
* This function will always take ownership of the passed
* ImageGenerator. Returns NULL on error.
*/
static SkImage* NewFromGenerator(SkImageGenerator*);
/**
* Construct a new SkImage based on the specified encoded data. Returns NULL on failure,
* which can mean that the format of the encoded data was not recognized/supported.
*
* Regardless of success or failure, the caller is responsible for managing their ownership
* of the data.
*/
static SkImage* NewFromData(SkData* data);
/**
* Create a new image from the specified descriptor. Note - the caller is responsible for
* managing the lifetime of the underlying platform texture.
*
* Will return NULL if the specified descriptor is unsupported.
*/
static SkImage* NewFromTexture(GrContext*, const GrBackendTextureDesc&,
SkAlphaType = kPremul_SkAlphaType);
/**
* Create a new image by copying the pixels from the specified descriptor. No reference is
* kept to the original platform texture.
*
* Will return NULL if the specified descriptor is unsupported.
*/
static SkImage* NewFromTextureCopy(GrContext*, const GrBackendTextureDesc&,
SkAlphaType = kPremul_SkAlphaType);
int width() const { return fWidth; }
int height() const { return fHeight; }
uint32_t uniqueID() const { return fUniqueID; }
virtual bool isOpaque() const { return false; }
/**
* 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() const;
virtual SkShader* newShader(SkShader::TileMode,
SkShader::TileMode,
const SkMatrix* localMatrix = NULL) const;
/**
* 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;
/**
* Copy the pixels from the image into the specified buffer (pixels + rowBytes),
* converting them into the requested format (dstInfo). The image pixels are read
* starting at the specified (srcX,srcY) location.
*
* The specified ImageInfo and (srcX,srcY) offset specifies a source rectangle
*
* srcR.setXYWH(srcX, srcY, dstInfo.width(), dstInfo.height());
*
* srcR is intersected with the bounds of the image. If this intersection is not empty,
* then we have two sets of pixels (of equal size). Replace the dst pixels with the
* corresponding src pixels, performing any colortype/alphatype transformations needed
* (in the case where the src and dst have different colortypes or alphatypes).
*
* This call can fail, returning false, for several reasons:
* - If srcR does not intersect the image bounds.
* - If the requested colortype/alphatype cannot be converted from the image's types.
*/
bool readPixels(const SkImageInfo& dstInfo, void* dstPixels, size_t dstRowBytes,
int srcX, int srcY) 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;
/**
* Return a new surface that is compatible with this image's internal representation
* (e.g. raster or gpu).
*
* If no surfaceprops are specified, the image will attempt to match the props of when it
* was created (if it came from a surface).
*/
SkSurface* newSurface(const SkImageInfo&, const SkSurfaceProps* = NULL) const;
const char* toString(SkString*) const;
/**
* Return an image that is a rescale of this image (using newWidth, newHeight).
*
* If subset is NULL, then the entire original image is used as the src for the scaling.
* If subset is not NULL, then it specifies subset of src-pixels used for scaling. If
* subset extends beyond the bounds of the original image, then NULL is returned.
*
* Notes:
* - newWidth and newHeight must be > 0 or NULL will be returned.
*
* - it is legal for the returned image to be the same instance as the src image
* (if the new dimensions == the src dimensions and subset is NULL or == src dimensions).
*
* - it is legal for the "scaled" image to have changed its SkAlphaType from unpremul
* to premul (as required by the impl). The image should draw (nearly) identically,
* since during drawing we will "apply the alpha" to the pixels. Future optimizations
* may take away this caveat, preserving unpremul.
*/
SkImage* newImage(int newWidth, int newHeight, const SkIRect* subset = NULL,
SkFilterQuality = kNone_SkFilterQuality) 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;
};
#endif