YUVBufferGenerator.h

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/* This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef YUVBufferGenerator_h

#define YUVBufferGenerator_h

#include <cstddef>

#include <cstdint>

#include "ImageContainer.h"

#include "Point.h"  // mozilla::gfx::IntSize

#include "Rect.h"   // mozilla::gfx::IntRect

#include "mozilla/AlreadyAddRefed.h"

#include "nsTArray.h"

// A helper object to generate of different YUV planes.

class YUVBufferGenerator {

 public:

  struct ChannelColor {

    uint8_t mY;

    uint8_t mCb;

    uint8_t mCr;

};

  enum class ChannelColorIndex : std::size_t {

    Black,

    White,

    Red,

};

  // 8-bit limited-range values from ITU-R BT.601-7, Table 4 and section 2.5:

  // https://www.itu.int/dms_pubrec/itu-r/rec/bt/r-rec-bt.601-7-201103-i!!pdf-e.pdf

  inline static constexpr ChannelColor kChannelColors[] = {

      {0x10, 0x80, 0x80},  // Black

      {0xEB, 0x80, 0x80},  // White

      {0x51, 0x5A, 0xF0},  // Red

};

  bool Init(

      const mozilla::gfx::IntSize& aSize,

      const ChannelColor& aColor =

          kChannelColors[static_cast<std::size_t>(ChannelColorIndex::Black)]);

  bool Init(const mozilla::gfx::IntSize& aSize, uint8_t aLuma, uint8_t aChroma);

  bool Init(

      const mozilla::gfx::IntRect& aPictureRect,

      const ChannelColor& aColor =

          kChannelColors[static_cast<std::size_t>(ChannelColorIndex::Black)]);

  mozilla::gfx::IntSize GetSize() const;

  already_AddRefed<mozilla::layers::Image> GenerateI420Image();

  already_AddRefed<mozilla::layers::Image> GenerateNV12Image();

  already_AddRefed<mozilla::layers::Image> GenerateNV21Image();

 private:

  void FillI420SourceBuffer();

  void FillNVSourceBuffer(uint8_t aFirstChromaValue,

                          uint8_t aSecondChromaValue);

  mozilla::gfx::IntRect mPictureRect;

  mozilla::gfx::IntSize mYDataSize;

  // Init checks that twice its width fits in int32_t, so NV12 and NV21 chroma

  // strides are representable.

  mozilla::gfx::IntSize mChromaSize;

  size_t mYPlaneLength = 0;

  size_t mChromaPlaneLength = 0;

  ChannelColor mColor =

      kChannelColors[static_cast<std::size_t>(ChannelColorIndex::Black)];

  nsTArray<uint8_t> mSourceBuffer;

};

#endif  // YUVBufferGenerator_h