SkImageGenerator.h

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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 "include/core/SkData.h"
#include "include/core/SkImageInfo.h"
#include "include/core/SkPixmap.h"
#include "include/core/SkRefCnt.h"
#include "include/core/SkYUVAPixmaps.h"
#include "include/private/base/SkAPI.h"
 
#if defined(SK_GRAPHITE)
#include "include/core/SkImage.h"
#include "include/gpu/graphite/Recorder.h"
#endif
 
#include <cstddef>
#include <cstdint>
 
class GrRecordingContext;
 
class SK_API SkImageGenerator {
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.
     */
    sk_sp<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(GrRecordingContext* context) const {
        return this->onIsValid(context);
    }
 
    /**
     *  Will this generator produce protected content
     */
    bool isProtected() const {
        return this->onIsProtected();
    }
 
    /**
     *  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.
     *
     *  @return true on success.
     */
    bool getPixels(const SkImageInfo& info, void* pixels, size_t rowBytes);
 
    bool getPixels(const SkPixmap& pm) {
        return this->getPixels(pm.info(), pm.writable_addr(), pm.rowBytes());
    }
 
    /**
     *  If decoding to YUV is supported, this returns true. Otherwise, this
     *  returns false and the caller will ignore output parameter yuvaPixmapInfo.
     *
     * @param  supportedDataTypes Indicates the data type/planar config combinations that are
     *                            supported by the caller. If the generator supports decoding to
     *                            YUV(A), but not as a type in supportedDataTypes, this method
     *                            returns false.
     *  @param yuvaPixmapInfo Output parameter that specifies the planar configuration, subsampling,
     *                        orientation, chroma siting, plane color types, and row bytes.
     */
    bool queryYUVAInfo(const SkYUVAPixmapInfo::SupportedDataTypes& supportedDataTypes,
                       SkYUVAPixmapInfo* yuvaPixmapInfo) const;
 
    /**
     *  Returns true on success and false on failure.
     *  This always attempts to perform a full decode. To get the planar
     *  configuration without decoding use queryYUVAInfo().
     *
     *  @param yuvaPixmaps  Contains preallocated pixmaps configured according to a successful call
     *                      to queryYUVAInfo().
     */
    bool getYUVAPlanes(const SkYUVAPixmaps& yuvaPixmaps);
 
    virtual bool isTextureGenerator() const { return false; }
 
protected:
    static constexpr int kNeedNewImageUniqueID = 0;
 
    SkImageGenerator(const SkImageInfo& info, uint32_t uniqueId = kNeedNewImageUniqueID);
 
    virtual sk_sp<SkData> onRefEncodedData() { return nullptr; }
    struct Options {};
    virtual bool onGetPixels(const SkImageInfo&, void*, size_t, const Options&) { return false; }
    virtual bool onIsValid(GrRecordingContext*) const { return true; }
    virtual bool onIsProtected() const { return false; }
    virtual bool onQueryYUVAInfo(const SkYUVAPixmapInfo::SupportedDataTypes&,
                                 SkYUVAPixmapInfo*) const { return false; }
    virtual bool onGetYUVAPlanes(const SkYUVAPixmaps&) { return false; }
 
    const SkImageInfo fInfo;
 
private:
    const uint32_t fUniqueID;
 
    SkImageGenerator(SkImageGenerator&&) = delete;
    SkImageGenerator(const SkImageGenerator&) = delete;
    SkImageGenerator& operator=(SkImageGenerator&&) = delete;
    SkImageGenerator& operator=(const SkImageGenerator&) = delete;
};
 
#endif  // SkImageGenerator_DEFINED