include/core/SkYUVAPixmaps.h

/*
 * Copyright 2020 Google LLC
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#ifndef SkYUVAPixmaps_DEFINED
#define SkYUVAPixmaps_DEFINED

#include "include/core/SkData.h"
#include "include/core/SkImageInfo.h"
#include "include/core/SkPixmap.h"
#include "include/core/SkYUVAInfo.h"
#include "include/private/SkTo.h"

#include <array>

struct SkYUVASizeInfo;
struct SkYUVAIndex;

/**
 * SkYUVAInfo combined with per-plane SkColorTypes and row bytes. Fully specifies the SkPixmaps
 * for a YUVA image without the actual pixel memory and data.
 */
class SK_API SkYUVAPixmapInfo {
public:
    static constexpr auto kMaxPlanes = SkYUVAInfo::kMaxPlanes;

    /** Default SkYUVAPixmapInfo is invalid. */
    SkYUVAPixmapInfo() = default;

    /**
     * Initializes the SkYUVAPixmapInfo from a SkYUVAInfo with per-plane color types and row bytes.
     * This will be invalid if the colorTypes aren't compatible with the SkYUVAInfo or if a
     * rowBytes entry is not valid for the plane dimensions and color type. Color type and
     * row byte values beyond the number of planes in SkYUVAInfo are ignored.
     */
    SkYUVAPixmapInfo(const SkYUVAInfo&,
                     const SkColorType[kMaxPlanes],
                     const size_t rowBytes[kMaxPlanes]);
    SkYUVAPixmapInfo(const SkYUVAPixmapInfo&) = default;

    SkYUVAPixmapInfo& operator=(const SkYUVAPixmapInfo&) = default;

    const SkYUVAInfo& yuvaInfo() const { return fYUVAInfo; }

    SkYUVColorSpace yuvColorSpace() const { return fYUVAInfo.yuvColorSpace(); }

    /** The number of SkPixmap planes, 0 if this SkYUVAPixmapInfo is invalid. */
    int numPlanes() const { return this->isValid() ? fYUVAInfo.numPlanes() : 0; }

    /**
     * Row bytes for the ith plane. Returns zero if i >= numPlanes() or this SkYUVAPixmapInfo is
     * invalid.
     */
    size_t rowBytes(int i) const { return fRowBytes[i]; }

    /** Image info for the ith plane, or default SkImageInfo if i >= numPlanes() */
    const SkImageInfo& planeInfo(int i) const { return fPlaneInfos[i]; }

    /**
     * Determine size to allocate for all planes. Optionally retrieves the per-plane sizes in
     * planeSizes if not null. If total size overflows will return SIZE_MAX and set all planeSizes
     * to SIZE_MAX. Returns 0 and fills planesSizes with 0 if this SkYUVAPixmapInfo is not valid.
     */
    size_t computeTotalBytes(size_t planeSizes[kMaxPlanes] = nullptr) const;

    /**
     * Takes an allocation that is assumed to be at least computeTotalBytes() in size and configures
     * the first numPlanes() entries in pixmaps array to point into that memory. The remaining
     * entries of pixmaps are default initialized. Fails if this SkYUVAPixmapInfo not valid.
     */
    bool initPixmapsFromSingleAllocation(void* memory, SkPixmap pixmaps[kMaxPlanes]) const;

    /**
     * Returns true if this has been configured with a non-empty dimensioned SkYUVAInfo with
     * compatible color types and row bytes.
     */
    bool isValid() const { return fPlaneInfos[0].colorType() != kUnknown_SkColorType; }

private:
    SkYUVAInfo fYUVAInfo;
    SkImageInfo fPlaneInfos[kMaxPlanes] = {};
    size_t fRowBytes[kMaxPlanes] = {};
    static_assert(kUnknown_SkColorType == 0, "default init isn't kUnknown");
};

/**
 * Helper to store SkPixmap planes as described by a SkYUVAPixmapInfo. Can be responsible for
 * allocating/freeing memory for pixmaps or use external memory.
 */
class SK_API SkYUVAPixmaps {
public:
    static constexpr auto kMaxPlanes = SkYUVAPixmapInfo::kMaxPlanes;

    /** Allocate space for pixmaps' pixels in the SkYUVAPixmaps. */
    static SkYUVAPixmaps Allocate(const SkYUVAPixmapInfo& yuvaPixmapInfo);

    /**
     * Use storage in SkData as backing store for pixmaps' pixels. SkData is retained by the
     * SkYUVAPixmaps.
     */
    static SkYUVAPixmaps FromData(const SkYUVAPixmapInfo&, sk_sp<SkData>);

    /**
     * Use passed in memory as backing store for pixmaps' pixels. Caller must ensure memory remains
     * allocated while pixmaps are in use. There must be at least
     * SkYUVAPixmapInfo::computeTotalBytes() allocated starting at memory.
     */
    static SkYUVAPixmaps FromExternalMemory(const SkYUVAPixmapInfo&, void* memory);

    /**
     * Wraps existing SkPixmaps. The SkYUVAPixmaps will have no ownership of the SkPixmaps' pixel
     * memory so the caller must ensure it remains valid. Will return an invalid SkYUVAPixmaps if
     * the SkYUVAInfo isn't compatible with the SkPixmap array (number of planes, plane dimensions,
     * sufficient color channels in planes, ...).
     */
    static SkYUVAPixmaps FromExternalPixmaps(const SkYUVAInfo&, const SkPixmap[kMaxPlanes]);

    /** Default SkYUVAPixmaps is invalid. */
    SkYUVAPixmaps() = default;
    ~SkYUVAPixmaps() = default;

    SkYUVAPixmaps(SkYUVAPixmaps&& that) = default;
    SkYUVAPixmaps& operator=(SkYUVAPixmaps&& that) = default;
    SkYUVAPixmaps(const SkYUVAPixmaps&) = default;
    SkYUVAPixmaps& operator=(const SkYUVAPixmaps& that) = default;

    /** Does have initialized pixmaps compatible with its SkYUVAInfo. */
    bool isValid() const { return !fYUVAInfo.dimensions().isEmpty(); }

    const SkYUVAInfo& yuvaInfo() const { return fYUVAInfo; }

    /** Number of pixmap planes or 0 if this SkYUVAPixmaps is invalid. */
    int numPlanes() const { return this->isValid() ? fYUVAInfo.numPlanes() : 0; }

    /**
     * Access the SkPixmap planes. They are default initialized if this is not a valid
     * SkYUVAPixmaps.
     */
    const std::array<SkPixmap, kMaxPlanes>& planes() const { return fPlanes; }

    /**
     * Get the ith SkPixmap plane. SkPixmap will be default initialized if i >= numPlanes or this
     * SkYUVAPixmaps is invalid.
     */
    const SkPixmap& plane(int i) const { return fPlanes[SkToSizeT(i)]; }

    /**
     * Conversion to legacy SkYUVA data structures.
     */
    bool toLegacy(SkYUVASizeInfo*, SkYUVAIndex[4]);

private:
    SkYUVAPixmaps(const SkYUVAPixmapInfo&, sk_sp<SkData>);
    SkYUVAPixmaps(const SkYUVAInfo&, const SkPixmap[kMaxPlanes]);

    SkYUVAInfo fYUVAInfo;
    std::array<SkPixmap, kMaxPlanes> fPlanes = {};
    sk_sp<SkData> fData;
};

#endif