src/image/SkImage_Base.h

/*
 * 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_Base_DEFINED
#define SkImage_Base_DEFINED

#include "SkImage.h"
#include "SkSurface.h"
#include <atomic>

#if SK_SUPPORT_GPU
#include "GrTextureProxy.h"
#include "SkTDArray.h"

class GrTexture;
#endif

#include <new>

class GrSamplerState;
class SkImageCacherator;

enum {
    kNeedNewImageUniqueID = 0
};

class SkImage_Base : public SkImage {
public:
    virtual ~SkImage_Base();

    // User: returns image info for this SkImage.
    // Implementors: if you can not return the value, return an invalid ImageInfo with w=0 & h=0
    // & unknown color space.
    virtual SkImageInfo onImageInfo() const = 0;
    virtual SkColorType onColorType() const = 0;
    virtual SkAlphaType onAlphaType() const = 0;

    virtual SkIRect onGetSubset() const {
        return { 0, 0, this->width(), this->height() };
    }

    virtual bool onPeekPixels(SkPixmap*) const { return false; }

    virtual const SkBitmap* onPeekBitmap() const { return nullptr; }

    virtual bool onReadPixels(const SkImageInfo& dstInfo, void* dstPixels, size_t dstRowBytes,
                              int srcX, int srcY, CachingHint) const = 0;

    virtual GrContext* context() const { return nullptr; }
#if SK_SUPPORT_GPU
    virtual GrTextureProxy* peekProxy() const { return nullptr; }
    virtual sk_sp<GrTextureProxy> asTextureProxyRef() const { return nullptr; }
    virtual sk_sp<GrTextureProxy> asTextureProxyRef(GrContext*, const GrSamplerState&,
                                                    SkColorSpace*, sk_sp<SkColorSpace>*,
                                                    SkScalar scaleAdjust[2]) const = 0;
    virtual sk_sp<GrTextureProxy> refPinnedTextureProxy(uint32_t* uniqueID) const {
        return nullptr;
    }

    virtual GrTexture* onGetTexture() const { return nullptr; }
#endif
    virtual GrBackendTexture onGetBackendTexture(bool flushPendingGrContextIO,
                                                 GrSurfaceOrigin* origin) const;

    virtual SkImageCacherator* peekCacherator() const { return nullptr; }

    // return a read-only copy of the pixels. We promise to not modify them,
    // but only inspect them (or encode them).
    virtual bool getROPixels(SkBitmap*, SkColorSpace* dstColorSpace,
                             CachingHint = kAllow_CachingHint) const = 0;

    virtual sk_sp<SkImage> onMakeSubset(const SkIRect&) const = 0;

    virtual sk_sp<SkData> onRefEncoded() const { return nullptr; }

    virtual bool onAsLegacyBitmap(SkBitmap*) const;

    // True for picture-backed and codec-backed
    virtual bool onIsLazyGenerated() const { return false; }

    // Call when this image is part of the key to a resourcecache entry. This allows the cache
    // to know automatically those entries can be purged when this SkImage deleted.
    void notifyAddedToRasterCache() const {
        fAddedToRasterCache.store(true);
    }

    virtual bool onIsValid(GrContext*) const = 0;

    virtual bool onPinAsTexture(GrContext*) const { return false; }
    virtual void onUnpinAsTexture(GrContext*) const {}

    virtual sk_sp<SkImage> onMakeColorSpace(sk_sp<SkColorSpace>, SkColorType) const = 0;
protected:
    SkImage_Base(int width, int height, uint32_t uniqueID);

#if SK_SUPPORT_GPU
    // When the SkImage_Base goes away, we will iterate over all the unique keys we've used and
    // send messages to the GrContexts to say the unique keys are no longer valid. The GrContexts
    // can then release the resources, conntected with the those unique keys, from their caches.
    SkTDArray<GrUniqueKeyInvalidatedMessage*> fUniqueKeyInvalidatedMessages;
#endif

private:
    // Set true by caches when they cache content that's derived from the current pixels.
    mutable std::atomic<bool> fAddedToRasterCache;

    typedef SkImage INHERITED;
};

static inline SkImage_Base* as_IB(SkImage* image) {
    return static_cast<SkImage_Base*>(image);
}

static inline SkImage_Base* as_IB(const sk_sp<SkImage>& image) {
    return static_cast<SkImage_Base*>(image.get());
}

static inline const SkImage_Base* as_IB(const SkImage* image) {
    return static_cast<const SkImage_Base*>(image);
}

#endif