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/*
* Copyright 2013 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef SkImageGenerator_DEFINED
#define SkImageGenerator_DEFINED
#include "SkColor.h"
#include "SkImageInfo.h"
class GrContext;
class SkBitmap;
class SkData;
class GrTexture;
class SkImageGenerator;
class SkMatrix;
class SkPaint;
class SkPicture;
/**
* Takes ownership of SkImageGenerator. If this method fails for
* whatever reason, it will return false and immediatetely delete
* the generator. If it succeeds, it will modify destination
* bitmap.
*
* If generator is NULL, will safely return false.
*
* If this fails or when the SkDiscardablePixelRef that is
* installed into destination is destroyed, it will call
* SkDELETE() on the generator. Therefore, generator should be
* allocated with SkNEW() or SkNEW_ARGS().
*
* @param destination Upon success, this bitmap will be
* configured and have a pixelref installed.
*
* @return true iff successful.
*/
SK_API bool SkInstallDiscardablePixelRef(SkImageGenerator*, SkBitmap* destination);
/**
* On success, installs a discardable pixelref into destination, based on encoded data.
* Regardless of success or failure, the caller must still balance their ownership of encoded.
*/
SK_API bool SkInstallDiscardablePixelRef(SkData* encoded, SkBitmap* destination);
/**
* An interface that allows a purgeable PixelRef (such as a
* SkDiscardablePixelRef) to decode and re-decode an image as needed.
*/
class SK_API SkImageGenerator : public SkNoncopyable {
public:
/**
* The PixelRef which takes ownership of this SkImageGenerator
* will call the image generator's destructor.
*/
virtual ~SkImageGenerator() { }
uint32_t uniqueID() const { return fUniqueID; }
/**
* Return a ref to the encoded (i.e. compressed) representation,
* of this data.
*
* If non-NULL is returned, the caller is responsible for calling
* unref() on the data when it is finished.
*/
SkData* refEncodedData() { return this->onRefEncodedData(); }
/**
* Return the ImageInfo associated with this generator.
*/
const SkImageInfo& getInfo() const { return fInfo; }
/**
* Decode into the given pixels, a block of memory of size at
* least (info.fHeight - 1) * rowBytes + (info.fWidth *
* bytesPerPixel)
*
* Repeated calls to this function should give the same results,
* allowing the PixelRef to be immutable.
*
* @param info A description of the format (config, size)
* expected by the caller. This can simply be identical
* to the info returned by getInfo().
*
* This contract also allows the caller to specify
* different output-configs, which the implementation can
* decide to support or not.
*
* A size that does not match getInfo() implies a request
* to scale. If the generator cannot perform this scale,
* it will return kInvalidScale.
*
* If info is kIndex8_SkColorType, then the caller must provide storage for up to 256
* SkPMColor values in ctable. On success the generator must copy N colors into that storage,
* (where N is the logical number of table entries) and set ctableCount to N.
*
* If info is not kIndex8_SkColorType, then the last two parameters may be NULL. If ctableCount
* is not null, it will be set to 0.
*
* @return true on success.
*/
bool getPixels(const SkImageInfo& info, void* pixels, size_t rowBytes,
SkPMColor ctable[], int* ctableCount);
/**
* Simplified version of getPixels() that asserts that info is NOT kIndex8_SkColorType and
* uses the default Options.
*/
bool getPixels(const SkImageInfo& info, void* pixels, size_t rowBytes);
/**
* If planes or rowBytes is NULL or if any entry in planes is NULL or if any entry in rowBytes
* is 0, this imagegenerator should output the sizes and return true if it can efficiently
* return YUV planar data. If it cannot, it should return false. Note that either planes and
* rowBytes are both fully defined and non NULL/non 0 or they are both NULL or have NULL or 0
* entries only. Having only partial planes/rowBytes information is not supported.
*
* If all planes and rowBytes entries are non NULL or non 0, then it should copy the
* associated YUV data into those planes of memory supplied by the caller. It should validate
* that the sizes match what it expected. If the sizes do not match, it should return false.
*/
bool getYUV8Planes(SkISize sizes[3], void* planes[3], size_t rowBytes[3],
SkYUVColorSpace* colorSpace);
/**
* If the generator can natively/efficiently return its pixels as a GPU image (backed by a
* texture) this will return that image. If not, this will return NULL.
*
* Regarding the GrContext parameter:
*
* The caller may pass NULL for the context. In that case the generator may assume that its
* internal context is current. If it has no internal context, then it should just return
* null.
*
* If the caller passes a non-null context, then the generator should only succeed if:
* - it has no intrinsic context, and will use the caller's
* - its internal context is the same
* - it can somehow convert its texture into one that is valid for the provided context.
*
* Regarding the SkImageUsageType parameter:
*
* If the context (the provided one or the generator's intrinsic one) determines that to
* support the specified usage, it must return a different sized texture it may,
* so the caller must inspect the texture's width/height and compare them to the generator's
* getInfo() width/height.
*/
GrTexture* generateTexture(GrContext*, SkImageUsageType, const SkIRect* subset = nullptr);
/**
* If the default image decoder system can interpret the specified (encoded) data, then
* this returns a new ImageGenerator for it. Otherwise this returns NULL. Either way
* the caller is still responsible for managing their ownership of the data.
*/
static SkImageGenerator* NewFromEncoded(SkData*);
/** Return a new image generator backed by the specified picture. If the size is empty or
* the picture is NULL, this returns NULL.
* The optional matrix and paint arguments are passed to drawPicture() at rasterization
* time.
*/
static SkImageGenerator* NewFromPicture(const SkISize&, const SkPicture*, const SkMatrix*,
const SkPaint*);
protected:
SkImageGenerator(const SkImageInfo& info);
virtual SkData* onRefEncodedData();
virtual bool onGetPixels(const SkImageInfo& info, void* pixels, size_t rowBytes,
SkPMColor ctable[], int* ctableCount);
virtual bool onGetYUV8Planes(SkISize sizes[3], void* planes[3], size_t rowBytes[3]);
virtual bool onGetYUV8Planes(SkISize sizes[3], void* planes[3], size_t rowBytes[3],
SkYUVColorSpace* colorSpace);
virtual GrTexture* onGenerateTexture(GrContext*, SkImageUsageType, const SkIRect*) {
return nullptr;
}
private:
const SkImageInfo fInfo;
const uint32_t fUniqueID;
// This is our default impl, which may be different on different platforms.
// It is called from NewFromEncoded() after it has checked for any runtime factory.
// The SkData will never be NULL, as that will have been checked by NewFromEncoded.
static SkImageGenerator* NewFromEncodedImpl(SkData*);
};
#endif // SkImageGenerator_DEFINED
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