text: // Copyright 2011 Google Inc. All Rights Reserved.
  //
  // Use of this source code is governed by a BSD-style license
  // that can be found in the COPYING file in the root of the source
  // tree. An additional intellectual property rights grant can be found
  // in the file PATENTS. All contributing project authors may
  // be found in the AUTHORS file in the root of the source tree.
  // -----------------------------------------------------------------------------
  //
  //   WebP encoder: main interface
  //
  // Author: Skal (pascal.massimino@gmail.com)
  
  #ifndef WEBP_WEBP_ENCODE_H_
  #define WEBP_WEBP_ENCODE_H_
  
  #include "./types.h"
  
  #ifdef __cplusplus
  extern "C" {
  #endif
  
  #define WEBP_ENCODER_ABI_VERSION 0x0209    // MAJOR(8b) + MINOR(8b)
  
  // Note: forward declaring enumerations is not allowed in (strict) C and C++,
  // the types are left here for reference.
  // typedef enum WebPImageHint WebPImageHint;
  // typedef enum WebPEncCSP WebPEncCSP;
  // typedef enum WebPPreset WebPPreset;
  // typedef enum WebPEncodingError WebPEncodingError;
  typedef struct WebPConfig WebPConfig;
  typedef struct WebPPicture WebPPicture;   // main structure for I/O
  typedef struct WebPAuxStats WebPAuxStats;
  typedef struct WebPMemoryWriter WebPMemoryWriter;
  
  // Return the encoder's version number, packed in hexadecimal using 8bits for
  // each of major/minor/revision. E.g: v2.5.7 is 0x020507.
  WEBP_EXTERN(int) WebPGetEncoderVersion(void);
  
  //------------------------------------------------------------------------------
  // One-stop-shop call! No questions asked:
  
  // Returns the size of the compressed data (pointed to by *output), or 0 if
  // an error occurred. The compressed data must be released by the caller
  // using the call 'WebPFree(*output)'.
  // These functions compress using the lossy format, and the quality_factor
  // can go from 0 (smaller output, lower quality) to 100 (best quality,
  // larger output).
  WEBP_EXTERN(size_t) WebPEncodeRGB(const uint8_t* rgb,
                                    int width, int height, int stride,
                                    float quality_factor, uint8_t** output);
  WEBP_EXTERN(size_t) WebPEncodeBGR(const uint8_t* bgr,
                                    int width, int height, int stride,
                                    float quality_factor, uint8_t** output);
  WEBP_EXTERN(size_t) WebPEncodeRGBA(const uint8_t* rgba,
                                     int width, int height, int stride,
                                     float quality_factor, uint8_t** output);
  WEBP_EXTERN(size_t) WebPEncodeBGRA(const uint8_t* bgra,
                                     int width, int height, int stride,
                                     float quality_factor, uint8_t** output);
  
  // These functions are the equivalent of the above, but compressing in a
  // lossless manner. Files are usually larger than lossy format, but will
  // not suffer any compression loss.
  WEBP_EXTERN(size_t) WebPEncodeLosslessRGB(const uint8_t* rgb,
                                            int width, int height, int stride,
                                            uint8_t** output);
  WEBP_EXTERN(size_t) WebPEncodeLosslessBGR(const uint8_t* bgr,
                                            int width, int height, int stride,
                                            uint8_t** output);
  WEBP_EXTERN(size_t) WebPEncodeLosslessRGBA(const uint8_t* rgba,
                                             int width, int height, int stride,
                                             uint8_t** output);
  WEBP_EXTERN(size_t) WebPEncodeLosslessBGRA(const uint8_t* bgra,
                                             int width, int height, int stride,
                                             uint8_t** output);
  
  // Releases memory returned by the WebPEncode*() functions above.
  WEBP_EXTERN(void) WebPFree(void* ptr);
  
  //------------------------------------------------------------------------------
  // Coding parameters
  
  // Image characteristics hint for the underlying encoder.
  typedef enum WebPImageHint {
    WEBP_HINT_DEFAULT = 0,  // default preset.
    WEBP_HINT_PICTURE,      // digital picture, like portrait, inner shot
    WEBP_HINT_PHOTO,        // outdoor photograph, with natural lighting
    WEBP_HINT_GRAPH,        // Discrete tone image (graph, map-tile etc).
    WEBP_HINT_LAST
  } WebPImageHint;
  
  // Compression parameters.
  struct WebPConfig {
    int lossless;           // Lossless encoding (0=lossy(default), 1=lossless).
    float quality;          // between 0 (smallest file) and 100 (biggest)
    int method;             // quality/speed trade-off (0=fast, 6=slower-better)
  
    WebPImageHint image_hint;  // Hint for image type (lossless only for now).
  
    // Parameters related to lossy compression only:
    int target_size;        // if non-zero, set the desired target size in bytes.
                            // Takes precedence over the 'compression' parameter.
    float target_PSNR;      // if non-zero, specifies the minimal distortion to
                            // try to achieve. Takes precedence over target_size.
    int segments;           // maximum number of segments to use, in [1..4]
    int sns_strength;       // Spatial Noise Shaping. 0=off, 100=maximum.
    int filter_strength;    // range: [0 = off .. 100 = strongest]
    int filter_sharpness;   // range: [0 = off .. 7 = least sharp]
    int filter_type;        // filtering type: 0 = simple, 1 = strong (only used
                            // if filter_strength > 0 or autofilter > 0)
    int autofilter;         // Auto adjust filter's strength [0 = off, 1 = on]
    int alpha_compression;  // Algorithm for encoding the alpha plane (0 = none,
                            // 1 = compressed with WebP lossless). Default is 1.
    int alpha_filtering;    // Predictive filtering method for alpha plane.
                            //  0: none, 1: fast, 2: best. Default if 1.
    int alpha_quality;      // Between 0 (smallest size) and 100 (lossless).
                            // Default is 100.
    int pass;               // number of entropy-analysis passes (in [1..10]).
  
    int show_compressed;    // if true, export the compressed picture back.
                            // In-loop filtering is not applied.
    int preprocessing;      // preprocessing filter:
                            // 0=none, 1=segment-smooth, 2=pseudo-random dithering
    int partitions;         // log2(number of token partitions) in [0..3]. Default
                            // is set to 0 for easier progressive decoding.
    int partition_limit;    // quality degradation allowed to fit the 512k limit
                            // on prediction modes coding (0: no degradation,
                            // 100: maximum possible degradation).
    int emulate_jpeg_size;  // If true, compression parameters will be remapped
                            // to better match the expected output size from
                            // JPEG compression. Generally, the output size will
                            // be similar but the degradation will be lower.
    int thread_level;       // If non-zero, try and use multi-threaded encoding.
    int low_memory;         // If set, reduce memory usage (but increase CPU use).
  
    int near_lossless;      // Near lossless encoding [0 = off(default) .. 100].
                            // This feature is experimental.
    int exact;              // if non-zero, preserve the exact RGB values under
                            // transparent area. Otherwise, discard this invisible
                            // RGB information for better compression. The default
                            // value is 0.
  
  #ifdef WEBP_EXPERIMENTAL_FEATURES
    int delta_palettization;
    uint32_t pad[2];        // padding for later use
  #else
    uint32_t pad[3];        // padding for later use
  #endif  // WEBP_EXPERIMENTAL_FEATURES
  };
  
  // Enumerate some predefined settings for WebPConfig, depending on the type
  // of source picture. These presets are used when calling WebPConfigPreset().
  typedef enum WebPPreset {
    WEBP_PRESET_DEFAULT = 0,  // default preset.
    WEBP_PRESET_PICTURE,      // digital picture, like portrait, inner shot
    WEBP_PRESET_PHOTO,        // outdoor photograph, with natural lighting
    WEBP_PRESET_DRAWING,      // hand or line drawing, with high-contrast details
    WEBP_PRESET_ICON,         // small-sized colorful images
    WEBP_PRESET_TEXT          // text-like
  } WebPPreset;
  
  // Internal, version-checked, entry point
  WEBP_EXTERN(int) WebPConfigInitInternal(WebPConfig*, WebPPreset, float, int);
  
  // Should always be called, to initialize a fresh WebPConfig structure before
  // modification. Returns false in case of version mismatch. WebPConfigInit()
  // must have succeeded before using the 'config' object.
  // Note that the default values are lossless=0 and quality=75.
  static WEBP_INLINE int WebPConfigInit(WebPConfig* config) {
    return WebPConfigInitInternal(config, WEBP_PRESET_DEFAULT, 75.f,
                                  WEBP_ENCODER_ABI_VERSION);
  }
  
  // This function will initialize the configuration according to a predefined
  // set of parameters (referred to by 'preset') and a given quality factor.
  // This function can be called as a replacement to WebPConfigInit(). Will
  // return false in case of error.
  static WEBP_INLINE int WebPConfigPreset(WebPConfig* config,
                                          WebPPreset preset, float quality) {
    return WebPConfigInitInternal(config, preset, quality,
                                  WEBP_ENCODER_ABI_VERSION);
  }
  
  // Activate the lossless compression mode with the desired efficiency level
  // between 0 (fastest, lowest compression) and 9 (slower, best compression).
  // A good default level is '6', providing a fair tradeoff between compression
  // speed and final compressed size.
  // This function will overwrite several fields from config: 'method', 'quality'
  // and 'lossless'. Returns false in case of parameter error.
  WEBP_EXTERN(int) WebPConfigLosslessPreset(WebPConfig* config, int level);
  
  // Returns true if 'config' is non-NULL and all configuration parameters are
  // within their valid ranges.
  WEBP_EXTERN(int) WebPValidateConfig(const WebPConfig* config);
  
  //------------------------------------------------------------------------------
  // Input / Output
  // Structure for storing auxiliary statistics (mostly for lossy encoding).
  
  struct WebPAuxStats {
    int coded_size;         // final size
  
    float PSNR[5];          // peak-signal-to-noise ratio for Y/U/V/All/Alpha
    int block_count[3];     // number of intra4/intra16/skipped macroblocks
    int header_bytes[2];    // approximate number of bytes spent for header
                            // and mode-partition #0
    int residual_bytes[3][4];  // approximate number of bytes spent for
                               // DC/AC/uv coefficients for each (0..3) segments.
    int segment_size[4];    // number of macroblocks in each segments
    int segment_quant[4];   // quantizer values for each segments
    int segment_level[4];   // filtering strength for each segments [0..63]
  
    int alpha_data_size;    // size of the transparency data
    int layer_data_size;    // size of the enhancement layer data
  
    // lossless encoder statistics
    uint32_t lossless_features;  // bit0:predictor bit1:cross-color transform
                                 // bit2:subtract-green bit3:color indexing
    int histogram_bits;          // number of precision bits of histogram
    int transform_bits;          // precision bits for transform
    int cache_bits;              // number of bits for color cache lookup
    int palette_size;            // number of color in palette, if used
    int lossless_size;           // final lossless size
    int lossless_hdr_size;       // lossless header (transform, huffman etc) size
    int lossless_data_size;      // lossless image data size
  
    uint32_t pad[2];        // padding for later use
  };
  
  // Signature for output function. Should return true if writing was successful.
  // data/data_size is the segment of data to write, and 'picture' is for
  // reference (and so one can make use of picture->custom_ptr).
  typedef int (*WebPWriterFunction)(const uint8_t* data, size_t data_size,
                                    const WebPPicture* picture);
  
  // WebPMemoryWrite: a special WebPWriterFunction that writes to memory using
  // the following WebPMemoryWriter object (to be set as a custom_ptr).
  struct WebPMemoryWriter {
    uint8_t* mem;       // final buffer (of size 'max_size', larger than 'size').
    size_t   size;      // final size
    size_t   max_size;  // total capacity
    uint32_t pad[1];    // padding for later use
  };
  
  // The following must be called first before any use.
  WEBP_EXTERN(void) WebPMemoryWriterInit(WebPMemoryWriter* writer);
  
  // The following must be called to deallocate writer->mem memory. The 'writer'
  // object itself is not deallocated.
  WEBP_EXTERN(void) WebPMemoryWriterClear(WebPMemoryWriter* writer);
  // The custom writer to be used with WebPMemoryWriter as custom_ptr. Upon
  // completion, writer.mem and writer.size will hold the coded data.
  // writer.mem must be freed by calling WebPMemoryWriterClear.
  WEBP_EXTERN(int) WebPMemoryWrite(const uint8_t* data, size_t data_size,
                                   const WebPPicture* picture);
  
  // Progress hook, called from time to time to report progress. It can return
  // false to request an abort of the encoding process, or true otherwise if
  // everything is OK.
  typedef int (*WebPProgressHook)(int percent, const WebPPicture* picture);
  
  // Color spaces.
  typedef enum WebPEncCSP {
    // chroma sampling
    WEBP_YUV420  = 0,        // 4:2:0
    WEBP_YUV420A = 4,        // alpha channel variant
    WEBP_CSP_UV_MASK = 3,    // bit-mask to get the UV sampling factors
    WEBP_CSP_ALPHA_BIT = 4   // bit that is set if alpha is present
  } WebPEncCSP;
  
  // Encoding error conditions.
  typedef enum WebPEncodingError {
    VP8_ENC_OK = 0,
    VP8_ENC_ERROR_OUT_OF_MEMORY,            // memory error allocating objects
    VP8_ENC_ERROR_BITSTREAM_OUT_OF_MEMORY,  // memory error while flushing bits
    VP8_ENC_ERROR_NULL_PARAMETER,           // a pointer parameter is NULL
    VP8_ENC_ERROR_INVALID_CONFIGURATION,    // configuration is invalid
    VP8_ENC_ERROR_BAD_DIMENSION,            // picture has invalid width/height
    VP8_ENC_ERROR_PARTITION0_OVERFLOW,      // partition is bigger than 512k
    VP8_ENC_ERROR_PARTITION_OVERFLOW,       // partition is bigger than 16M
    VP8_ENC_ERROR_BAD_WRITE,                // error while flushing bytes
    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. Results
  // are in dB, stored in result[] in the Y/U/V/Alpha/All or B/G/R/A/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
  // coordinates (left, top) as well as its width and height. This rectangle
  // must be fully be comprised inside the 'src' source picture. If the source
  // picture uses the YUV420 colorspace, the top and left coordinates will be
  // snapped to even values.
  WEBP_EXTERN(int) WebPPictureCrop(WebPPicture* picture,
                                   int left, int top, int width, int height);
  
  // Extracts a view from 'src' picture into 'dst'. The rectangle for the view
  // is defined by the top-left corner pixel coordinates (left, top) as well
  // as its width and height. This rectangle must be fully be comprised inside
  // the 'src' source picture. If the source picture uses the YUV420 colorspace,
  // the top and left coordinates will be snapped to even values.
  // Picture 'src' must out-live 'dst' picture. Self-extraction of view is allowed
  // ('src' equal to 'dst') as a mean of fast-cropping (but note that doing so,
  // the original dimension will be lost). Picture 'dst' need not be initialized
  // with WebPPictureInit() if it is different from 'src', since its content will
  // be overwritten.
  // Returns false in case of memory allocation error or invalid parameters.
  WEBP_EXTERN(int) WebPPictureView(const WebPPicture* src,
                                   int left, int top, int width, int height,
                                   WebPPicture* dst);
  
  // Returns true if the 'picture' is actually a view and therefore does
  // not own the memory for pixels.
  WEBP_EXTERN(int) WebPPictureIsView(const WebPPicture* picture);
  
  // Rescale a picture to new dimension width x height.
  // If either 'width' or 'height' (but not both) is 0 the corresponding
  // dimension will be calculated preserving the aspect ratio.
  // No gamma correction is applied.
  // Returns false in case of error (invalid parameter or insufficient memory).
  WEBP_EXTERN(int) WebPPictureRescale(WebPPicture* pic, int width, int height);
  
  // Colorspace conversion function to import RGB samples.
  // Previous buffer will be free'd, if any.
  // *rgb buffer should have a size of at least height * rgb_stride.
  // Returns false in case of memory error.
  WEBP_EXTERN(int) WebPPictureImportRGB(
      WebPPicture* picture, const uint8_t* rgb, int rgb_stride);
  // Same, but for RGBA buffer.
  WEBP_EXTERN(int) WebPPictureImportRGBA(
      WebPPicture* picture, const uint8_t* rgba, int rgba_stride);
  // Same, but for RGBA buffer. Imports the RGB direct from the 32-bit format
  // input buffer ignoring the alpha channel. Avoids needing to copy the data
  // to a temporary 24-bit RGB buffer to import the RGB only.
  WEBP_EXTERN(int) WebPPictureImportRGBX(
      WebPPicture* picture, const uint8_t* rgbx, int rgbx_stride);
  
  // Variants of the above, but taking BGR(A|X) input.
  WEBP_EXTERN(int) WebPPictureImportBGR(
      WebPPicture* picture, const uint8_t* bgr, int bgr_stride);
  WEBP_EXTERN(int) WebPPictureImportBGRA(
      WebPPicture* picture, const uint8_t* bgra, int bgra_stride);
  WEBP_EXTERN(int) WebPPictureImportBGRX(
      WebPPicture* picture, const uint8_t* bgrx, int bgrx_stride);
  
  // Converts picture->argb data to the YUV420A format. The 'colorspace'
  // parameter is deprecated and should be equal to WEBP_YUV420.
  // Upon return, picture->use_argb is set to false. The presence of real
  // non-opaque transparent values is detected, and 'colorspace' will be
  // adjusted accordingly. Note that this method is lossy.
  // Returns false in case of error.
  WEBP_EXTERN(int) WebPPictureARGBToYUVA(WebPPicture* picture,
                                         WebPEncCSP /*colorspace = WEBP_YUV420*/);
  
  // Same as WebPPictureARGBToYUVA(), but the conversion is done using
  // pseudo-random dithering with a strength 'dithering' between
  // 0.0 (no dithering) and 1.0 (maximum dithering). This is useful
  // for photographic picture.
  WEBP_EXTERN(int) WebPPictureARGBToYUVADithered(
      WebPPicture* picture, WebPEncCSP colorspace, float dithering);
  
  // Performs 'smart' RGBA->YUVA420 downsampling and colorspace conversion.
  // Downsampling is handled with extra care in case of color clipping. This
  // method is roughly 2x slower than WebPPictureARGBToYUVA() but produces better
  // YUV representation.
  // Returns false in case of error.
  WEBP_EXTERN(int) WebPPictureSmartARGBToYUVA(WebPPicture* picture);
  
  // Converts picture->yuv to picture->argb and sets picture->use_argb to true.
  // The input format must be YUV_420 or YUV_420A.
  // Note that the use of this method is discouraged if one has access to the
  // raw ARGB samples, since using YUV420 is comparatively lossy. Also, the
  // conversion from YUV420 to ARGB incurs a small loss too.
  // Returns false in case of error.
  WEBP_EXTERN(int) WebPPictureYUVAToARGB(WebPPicture* picture);
  
  // Helper function: given a width x height plane of RGBA or YUV(A) samples
  // clean-up the YUV or RGB samples under fully transparent area, to help
  // compressibility (no guarantee, though).
  WEBP_EXTERN(void) WebPCleanupTransparentArea(WebPPicture* picture);
  
  // Scan the picture 'picture' for the presence of non fully opaque alpha values.
  // Returns true in such case. Otherwise returns false (indicating that the
  // alpha plane can be ignored altogether e.g.).
  WEBP_EXTERN(int) WebPPictureHasTransparency(const WebPPicture* picture);
  
  // Remove the transparency information (if present) by blending the color with
  // the background color 'background_rgb' (specified as 24bit RGB triplet).
  // After this call, all alpha values are reset to 0xff.
  WEBP_EXTERN(void) WebPBlendAlpha(WebPPicture* pic, uint32_t background_rgb);
  
  //------------------------------------------------------------------------------
  // Main call
  
  // Main encoding call, after config and picture have been initialized.
  // 'picture' must be less than 16384x16384 in dimension (cf WEBP_MAX_DIMENSION),
  // and the 'config' object must be a valid one.
  // Returns false in case of error, true otherwise.
  // In case of error, picture->error_code is updated accordingly.
  // 'picture' can hold the source samples in both YUV(A) or ARGB input, depending
  // on the value of 'picture->use_argb'. It is highly recommended to use
  // the former for lossy encoding, and the latter for lossless encoding
  // (when config.lossless is true). Automatic conversion from one format to
  // another is provided but they both incur some loss.
  WEBP_EXTERN(int) WebPEncode(const WebPConfig* config, WebPPicture* picture);
  
  //------------------------------------------------------------------------------
  
  #ifdef __cplusplus
  }    // extern "C"
  #endif
  
  #endif  /* WEBP_WEBP_ENCODE_H_ */
  