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src/Source/LibWebP/src/webp/encode.h  view on Meta::CPAN

  VP8_ENC_ERROR_FILE_TOO_BIG,             // file is bigger than 4G
  VP8_ENC_ERROR_USER_ABORT,               // abort request by user
  VP8_ENC_ERROR_LAST                      // list terminator. always last.
} WebPEncodingError;

// maximum width/height allowed (inclusive), in pixels
#define WEBP_MAX_DIMENSION 16383

// Main exchange structure (input samples, output bytes, statistics)
struct WebPPicture {
  //   INPUT
  //////////////
  // Main flag for encoder selecting between ARGB or YUV input.
  // It is recommended to use ARGB input (*argb, argb_stride) for lossless
  // compression, and YUV input (*y, *u, *v, etc.) for lossy compression
  // since these are the respective native colorspace for these formats.
  int use_argb;

  // YUV input (mostly used for input to lossy compression)
  WebPEncCSP colorspace;     // colorspace: should be YUV420 for now (=Y'CbCr).
  int width, height;         // dimensions (less or equal to WEBP_MAX_DIMENSION)
  uint8_t *y, *u, *v;        // pointers to luma/chroma planes.
  int y_stride, uv_stride;   // luma/chroma strides.
  uint8_t* a;                // pointer to the alpha plane
  int a_stride;              // stride of the alpha plane
  uint32_t pad1[2];          // padding for later use

  // ARGB input (mostly used for input to lossless compression)
  uint32_t* argb;            // Pointer to argb (32 bit) plane.
  int argb_stride;           // This is stride in pixels units, not bytes.
  uint32_t pad2[3];          // padding for later use

  //   OUTPUT
  ///////////////
  // Byte-emission hook, to store compressed bytes as they are ready.
  WebPWriterFunction writer;  // can be NULL
  void* custom_ptr;           // can be used by the writer.

  // map for extra information (only for lossy compression mode)
  int extra_info_type;    // 1: intra type, 2: segment, 3: quant
                          // 4: intra-16 prediction mode,
                          // 5: chroma prediction mode,
                          // 6: bit cost, 7: distortion
  uint8_t* extra_info;    // if not NULL, points to an array of size
                          // ((width + 15) / 16) * ((height + 15) / 16) that
                          // will be filled with a macroblock map, depending
                          // on extra_info_type.

  //   STATS AND REPORTS
  ///////////////////////////
  // Pointer to side statistics (updated only if not NULL)
  WebPAuxStats* stats;

  // Error code for the latest error encountered during encoding
  WebPEncodingError error_code;

  // If not NULL, report progress during encoding.
  WebPProgressHook progress_hook;

  void* user_data;        // this field is free to be set to any value and
                          // used during callbacks (like progress-report e.g.).

  uint32_t pad3[3];       // padding for later use

  // Unused for now
  uint8_t *pad4, *pad5;
  uint32_t pad6[8];       // padding for later use

  // PRIVATE FIELDS
  ////////////////////
  void* memory_;          // row chunk of memory for yuva planes
  void* memory_argb_;     // and for argb too.
  void* pad7[2];          // padding for later use
};

// Internal, version-checked, entry point
WEBP_EXTERN(int) WebPPictureInitInternal(WebPPicture*, int);

// Should always be called, to initialize the structure. Returns false in case
// of version mismatch. WebPPictureInit() must have succeeded before using the
// 'picture' object.
// Note that, by default, use_argb is false and colorspace is WEBP_YUV420.
static WEBP_INLINE int WebPPictureInit(WebPPicture* picture) {
  return WebPPictureInitInternal(picture, WEBP_ENCODER_ABI_VERSION);
}

//------------------------------------------------------------------------------
// WebPPicture utils

// Convenience allocation / deallocation based on picture->width/height:
// Allocate y/u/v buffers as per colorspace/width/height specification.
// Note! This function will free the previous buffer if needed.
// Returns false in case of memory error.
WEBP_EXTERN(int) WebPPictureAlloc(WebPPicture* picture);

// Release the memory allocated by WebPPictureAlloc() or WebPPictureImport*().
// Note that this function does _not_ free the memory used by the 'picture'
// object itself.
// Besides memory (which is reclaimed) all other fields of 'picture' are
// preserved.
WEBP_EXTERN(void) WebPPictureFree(WebPPicture* picture);

// Copy the pixels of *src into *dst, using WebPPictureAlloc. Upon return, *dst
// will fully own the copied pixels (this is not a view). The 'dst' picture need
// not be initialized as its content is overwritten.
// Returns false in case of memory allocation error.
WEBP_EXTERN(int) WebPPictureCopy(const WebPPicture* src, WebPPicture* dst);

// Compute PSNR, SSIM or LSIM distortion metric between two pictures.
// Result is in dB, stores in result[] in the Y/U/V/Alpha/All order.
// Returns false in case of error (src and ref don't have same dimension, ...)
// Warning: this function is rather CPU-intensive.
WEBP_EXTERN(int) WebPPictureDistortion(
    const WebPPicture* src, const WebPPicture* ref,
    int metric_type,           // 0 = PSNR, 1 = SSIM, 2 = LSIM
    float result[5]);

// self-crops a picture to the rectangle defined by top/left/width/height.
// Returns false in case of memory allocation error, or if the rectangle is
// outside of the source picture.
// The rectangle for the view is defined by the top-left corner pixel