SkImageGenerator.h

/*
 * 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 {
public:
    virtual ~SkImageGenerator() { }

    uint32_t uniqueID() const { return fUniqueID; }

    SkData* refEncodedData() {
        return this->onRefEncodedData();
    }

    const SkImageInfo& getInfo() const { return fInfo; }

    bool isValid(GrContext* context) const {
        return this->onIsValid(context);
    }

    struct Options {
        Options()
            : fBehavior(SkTransferFunctionBehavior::kIgnore)
        {}

        SkTransferFunctionBehavior fBehavior;
    };
    bool getPixels(const SkImageInfo& info, void* pixels, size_t rowBytes, const Options* options);

    bool getPixels(const SkImageInfo& info, void* pixels, size_t rowBytes);

    bool queryYUV8(SkYUVSizeInfo* sizeInfo, SkYUVColorSpace* colorSpace) const;

    bool getYUV8Planes(const SkYUVSizeInfo& sizeInfo, void* planes[3]);

#if SK_SUPPORT_GPU

    sk_sp<GrTextureProxy> generateTexture(GrContext*, const SkImageInfo& info,
                                          const SkIPoint& origin);
#endif

    static std::unique_ptr<SkImageGenerator> MakeFromEncoded(sk_sp<SkData>);

    static std::unique_ptr<SkImageGenerator> MakeFromPicture(const SkISize&, sk_sp<SkPicture>,
                                                             const SkMatrix*, const SkPaint*,
                                                             SkImage::BitDepth,
                                                             sk_sp<SkColorSpace>);

protected:
    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; }

#if SK_SUPPORT_GPU
    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&);   // returns nullptr
#endif

private:
    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