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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 "SkBitmap.h"
#include "SkColor.h"
#include "SkImage.h"
#include "SkImageInfo.h"
#include "SkYUVSizeInfo.h"
class GrContext;
class GrContextThreadSafeProxy;
class GrTextureProxy;
class GrSamplerParams;
class SkBitmap;
class SkData;
class SkMatrix;
class SkPaint;
class SkPicture;
class SK_API SkImageGenerator : public SkNoncopyable {
* 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; }
* Can this generator be used to produce images that will be drawable to the specified context
* (or to CPU, if context is nullptr)?
bool isValid(GrContext* context) const {
return this->onIsValid(context);
* 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
* 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 false.
* kIndex_8_SkColorType is not supported.
* @return true on success.
struct Options {
: fBehavior(SkTransferFunctionBehavior::kIgnore)
SkTransferFunctionBehavior fBehavior;
bool getPixels(const SkImageInfo& info, void* pixels, size_t rowBytes, const Options* options);
* Simplified version of getPixels() that uses the default Options.
bool getPixels(const SkImageInfo& info, void* pixels, size_t rowBytes);
* If decoding to YUV is supported, this returns true. Otherwise, this
* returns false and does not modify any of the parameters.
* @param sizeInfo Output parameter indicating the sizes and required
* allocation widths of the Y, U, and V planes.
* @param colorSpace Output parameter.
bool queryYUV8(SkYUVSizeInfo* sizeInfo, SkYUVColorSpace* colorSpace) const;
* Returns true on success and false on failure.
* This always attempts to perform a full decode. If the client only
* wants size, it should call queryYUV8().
* @param sizeInfo Needs to exactly match the values returned by the
* query, except the WidthBytes may be larger than the
* recommendation (but not smaller).
* @param planes Memory for each of the Y, U, and V planes.
bool getYUV8Planes(const SkYUVSizeInfo& sizeInfo, void* planes[3]);
* 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.
* This routine also supports retrieving only a subset of the pixels. That subset is specified
* by the following rectangle:
* subset = SkIRect::MakeXYWH(origin.x(), origin.y(), info.width(), info.height())
* If subset is not contained inside the generator's bounds, this returns false.
* whole = SkIRect::MakeWH(getInfo().width(), getInfo().height())
* if (!whole.contains(subset)) {
* return false;
* }
* Regarding the GrContext parameter:
* It must be non-NULL. The generator should only succeed if:
* - its internal context is the same
* - it can somehow convert its texture into one that is valid for the provided context.
sk_sp<GrTextureProxy> generateTexture(GrContext*, const SkImageInfo& info,
const SkIPoint& origin,
SkTransferFunctionBehavior behavior);
* 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 std::unique_ptr<SkImageGenerator> MakeFromEncoded(sk_sp<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 std::unique_ptr<SkImageGenerator> MakeFromPicture(const SkISize&, sk_sp<SkPicture>,
const SkMatrix*, const SkPaint*,
enum {
kNeedNewImageUniqueID = 0
SkImageGenerator(const SkImageInfo& info, uint32_t uniqueId = kNeedNewImageUniqueID);
virtual SkData* onRefEncodedData() { return nullptr; }
virtual bool onGetPixels(const SkImageInfo&, void*, size_t, const Options&) { return false; }
virtual bool onIsValid(GrContext*) const { return true; }
virtual bool onQueryYUV8(SkYUVSizeInfo*, SkYUVColorSpace*) const { return false; }
virtual bool onGetYUV8Planes(const SkYUVSizeInfo&, void*[3] /*planes*/) { return false; }
enum class TexGenType {
kNone, //image generator does not implement onGenerateTexture
kCheap, //onGenerateTexture is implemented and it is fast (does not render offscreen)
kExpensive, //onGenerateTexture is implemented and it is relatively slow
virtual TexGenType onCanGenerateTexture() const { return TexGenType::kNone; }
virtual sk_sp<GrTextureProxy> onGenerateTexture(GrContext*, const SkImageInfo&, const SkIPoint&,
SkTransferFunctionBehavior); // returns nullptr
const SkImageInfo fInfo;
const uint32_t fUniqueID;
friend class SkImage_Lazy;
// 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 std::unique_ptr<SkImageGenerator> MakeFromEncodedImpl(sk_sp<SkData>);
#endif // SkImageGenerator_DEFINED