1// Copyright 2011 Google Inc. All Rights Reserved. 2// 3// Use of this source code is governed by a BSD-style license 4// that can be found in the COPYING file in the root of the source 5// tree. An additional intellectual property rights grant can be found 6// in the file PATENTS. All contributing project authors may 7// be found in the AUTHORS file in the root of the source tree. 8// ----------------------------------------------------------------------------- 9// 10// WebP encoder: main interface 11// 12// Author: Skal (pascal.massimino@gmail.com) 13 14#ifndef WEBP_WEBP_ENCODE_H_ 15#define WEBP_WEBP_ENCODE_H_ 16 17#include "./types.h" 18 19#ifdef __cplusplus 20extern "C" { 21#endif 22 23#define WEBP_ENCODER_ABI_VERSION 0x0209 // MAJOR(8b) + MINOR(8b) 24 25// Note: forward declaring enumerations is not allowed in (strict) C and C++, 26// the types are left here for reference. 27// typedef enum WebPImageHint WebPImageHint; 28// typedef enum WebPEncCSP WebPEncCSP; 29// typedef enum WebPPreset WebPPreset; 30// typedef enum WebPEncodingError WebPEncodingError; 31typedef struct WebPConfig WebPConfig; 32typedef struct WebPPicture WebPPicture; // main structure for I/O 33typedef struct WebPAuxStats WebPAuxStats; 34typedef struct WebPMemoryWriter WebPMemoryWriter; 35 36// Return the encoder's version number, packed in hexadecimal using 8bits for 37// each of major/minor/revision. E.g: v2.5.7 is 0x020507. 38WEBP_EXTERN(int) WebPGetEncoderVersion(void); 39 40//------------------------------------------------------------------------------ 41// One-stop-shop call! No questions asked: 42 43// Returns the size of the compressed data (pointed to by *output), or 0 if 44// an error occurred. The compressed data must be released by the caller 45// using the call 'WebPFree(*output)'. 46// These functions compress using the lossy format, and the quality_factor 47// can go from 0 (smaller output, lower quality) to 100 (best quality, 48// larger output). 49WEBP_EXTERN(size_t) WebPEncodeRGB(const uint8_t* rgb, 50 int width, int height, int stride, 51 float quality_factor, uint8_t** output); 52WEBP_EXTERN(size_t) WebPEncodeBGR(const uint8_t* bgr, 53 int width, int height, int stride, 54 float quality_factor, uint8_t** output); 55WEBP_EXTERN(size_t) WebPEncodeRGBA(const uint8_t* rgba, 56 int width, int height, int stride, 57 float quality_factor, uint8_t** output); 58WEBP_EXTERN(size_t) WebPEncodeBGRA(const uint8_t* bgra, 59 int width, int height, int stride, 60 float quality_factor, uint8_t** output); 61 62// These functions are the equivalent of the above, but compressing in a 63// lossless manner. Files are usually larger than lossy format, but will 64// not suffer any compression loss. 65WEBP_EXTERN(size_t) WebPEncodeLosslessRGB(const uint8_t* rgb, 66 int width, int height, int stride, 67 uint8_t** output); 68WEBP_EXTERN(size_t) WebPEncodeLosslessBGR(const uint8_t* bgr, 69 int width, int height, int stride, 70 uint8_t** output); 71WEBP_EXTERN(size_t) WebPEncodeLosslessRGBA(const uint8_t* rgba, 72 int width, int height, int stride, 73 uint8_t** output); 74WEBP_EXTERN(size_t) WebPEncodeLosslessBGRA(const uint8_t* bgra, 75 int width, int height, int stride, 76 uint8_t** output); 77 78// Releases memory returned by the WebPEncode*() functions above. 79WEBP_EXTERN(void) WebPFree(void* ptr); 80 81//------------------------------------------------------------------------------ 82// Coding parameters 83 84// Image characteristics hint for the underlying encoder. 85typedef enum WebPImageHint { 86 WEBP_HINT_DEFAULT = 0, // default preset. 87 WEBP_HINT_PICTURE, // digital picture, like portrait, inner shot 88 WEBP_HINT_PHOTO, // outdoor photograph, with natural lighting 89 WEBP_HINT_GRAPH, // Discrete tone image (graph, map-tile etc). 90 WEBP_HINT_LAST 91} WebPImageHint; 92 93// Compression parameters. 94struct WebPConfig { 95 int lossless; // Lossless encoding (0=lossy(default), 1=lossless). 96 float quality; // between 0 (smallest file) and 100 (biggest) 97 int method; // quality/speed trade-off (0=fast, 6=slower-better) 98 99 WebPImageHint image_hint; // Hint for image type (lossless only for now). 100 101 // Parameters related to lossy compression only: 102 int target_size; // if non-zero, set the desired target size in bytes. 103 // Takes precedence over the 'compression' parameter. 104 float target_PSNR; // if non-zero, specifies the minimal distortion to 105 // try to achieve. Takes precedence over target_size. 106 int segments; // maximum number of segments to use, in [1..4] 107 int sns_strength; // Spatial Noise Shaping. 0=off, 100=maximum. 108 int filter_strength; // range: [0 = off .. 100 = strongest] 109 int filter_sharpness; // range: [0 = off .. 7 = least sharp] 110 int filter_type; // filtering type: 0 = simple, 1 = strong (only used 111 // if filter_strength > 0 or autofilter > 0) 112 int autofilter; // Auto adjust filter's strength [0 = off, 1 = on] 113 int alpha_compression; // Algorithm for encoding the alpha plane (0 = none, 114 // 1 = compressed with WebP lossless). Default is 1. 115 int alpha_filtering; // Predictive filtering method for alpha plane. 116 // 0: none, 1: fast, 2: best. Default if 1. 117 int alpha_quality; // Between 0 (smallest size) and 100 (lossless). 118 // Default is 100. 119 int pass; // number of entropy-analysis passes (in [1..10]). 120 121 int show_compressed; // if true, export the compressed picture back. 122 // In-loop filtering is not applied. 123 int preprocessing; // preprocessing filter: 124 // 0=none, 1=segment-smooth, 2=pseudo-random dithering 125 int partitions; // log2(number of token partitions) in [0..3]. Default 126 // is set to 0 for easier progressive decoding. 127 int partition_limit; // quality degradation allowed to fit the 512k limit 128 // on prediction modes coding (0: no degradation, 129 // 100: maximum possible degradation). 130 int emulate_jpeg_size; // If true, compression parameters will be remapped 131 // to better match the expected output size from 132 // JPEG compression. Generally, the output size will 133 // be similar but the degradation will be lower. 134 int thread_level; // If non-zero, try and use multi-threaded encoding. 135 int low_memory; // If set, reduce memory usage (but increase CPU use). 136 137 int near_lossless; // Near lossless encoding [0 = off(default) .. 100]. 138 // This feature is experimental. 139 int exact; // if non-zero, preserve the exact RGB values under 140 // transparent area. Otherwise, discard this invisible 141 // RGB information for better compression. The default 142 // value is 0. 143 144#ifdef WEBP_EXPERIMENTAL_FEATURES 145 int delta_palettization; 146 uint32_t pad[2]; // padding for later use 147#else 148 uint32_t pad[3]; // padding for later use 149#endif // WEBP_EXPERIMENTAL_FEATURES 150}; 151 152// Enumerate some predefined settings for WebPConfig, depending on the type 153// of source picture. These presets are used when calling WebPConfigPreset(). 154typedef enum WebPPreset { 155 WEBP_PRESET_DEFAULT = 0, // default preset. 156 WEBP_PRESET_PICTURE, // digital picture, like portrait, inner shot 157 WEBP_PRESET_PHOTO, // outdoor photograph, with natural lighting 158 WEBP_PRESET_DRAWING, // hand or line drawing, with high-contrast details 159 WEBP_PRESET_ICON, // small-sized colorful images 160 WEBP_PRESET_TEXT // text-like 161} WebPPreset; 162 163// Internal, version-checked, entry point 164WEBP_EXTERN(int) WebPConfigInitInternal(WebPConfig*, WebPPreset, float, int); 165 166// Should always be called, to initialize a fresh WebPConfig structure before 167// modification. Returns false in case of version mismatch. WebPConfigInit() 168// must have succeeded before using the 'config' object. 169// Note that the default values are lossless=0 and quality=75. 170static WEBP_INLINE int WebPConfigInit(WebPConfig* config) { 171 return WebPConfigInitInternal(config, WEBP_PRESET_DEFAULT, 75.f, 172 WEBP_ENCODER_ABI_VERSION); 173} 174 175// This function will initialize the configuration according to a predefined 176// set of parameters (referred to by 'preset') and a given quality factor. 177// This function can be called as a replacement to WebPConfigInit(). Will 178// return false in case of error. 179static WEBP_INLINE int WebPConfigPreset(WebPConfig* config, 180 WebPPreset preset, float quality) { 181 return WebPConfigInitInternal(config, preset, quality, 182 WEBP_ENCODER_ABI_VERSION); 183} 184 185// Activate the lossless compression mode with the desired efficiency level 186// between 0 (fastest, lowest compression) and 9 (slower, best compression). 187// A good default level is '6', providing a fair tradeoff between compression 188// speed and final compressed size. 189// This function will overwrite several fields from config: 'method', 'quality' 190// and 'lossless'. Returns false in case of parameter error. 191WEBP_EXTERN(int) WebPConfigLosslessPreset(WebPConfig* config, int level); 192 193// Returns true if 'config' is non-NULL and all configuration parameters are 194// within their valid ranges. 195WEBP_EXTERN(int) WebPValidateConfig(const WebPConfig* config); 196 197//------------------------------------------------------------------------------ 198// Input / Output 199// Structure for storing auxiliary statistics (mostly for lossy encoding). 200 201struct WebPAuxStats { 202 int coded_size; // final size 203 204 float PSNR[5]; // peak-signal-to-noise ratio for Y/U/V/All/Alpha 205 int block_count[3]; // number of intra4/intra16/skipped macroblocks 206 int header_bytes[2]; // approximate number of bytes spent for header 207 // and mode-partition #0 208 int residual_bytes[3][4]; // approximate number of bytes spent for 209 // DC/AC/uv coefficients for each (0..3) segments. 210 int segment_size[4]; // number of macroblocks in each segments 211 int segment_quant[4]; // quantizer values for each segments 212 int segment_level[4]; // filtering strength for each segments [0..63] 213 214 int alpha_data_size; // size of the transparency data 215 int layer_data_size; // size of the enhancement layer data 216 217 // lossless encoder statistics 218 uint32_t lossless_features; // bit0:predictor bit1:cross-color transform 219 // bit2:subtract-green bit3:color indexing 220 int histogram_bits; // number of precision bits of histogram 221 int transform_bits; // precision bits for transform 222 int cache_bits; // number of bits for color cache lookup 223 int palette_size; // number of color in palette, if used 224 int lossless_size; // final lossless size 225 int lossless_hdr_size; // lossless header (transform, huffman etc) size 226 int lossless_data_size; // lossless image data size 227 228 uint32_t pad[2]; // padding for later use 229}; 230 231// Signature for output function. Should return true if writing was successful. 232// data/data_size is the segment of data to write, and 'picture' is for 233// reference (and so one can make use of picture->custom_ptr). 234typedef int (*WebPWriterFunction)(const uint8_t* data, size_t data_size, 235 const WebPPicture* picture); 236 237// WebPMemoryWrite: a special WebPWriterFunction that writes to memory using 238// the following WebPMemoryWriter object (to be set as a custom_ptr). 239struct WebPMemoryWriter { 240 uint8_t* mem; // final buffer (of size 'max_size', larger than 'size'). 241 size_t size; // final size 242 size_t max_size; // total capacity 243 uint32_t pad[1]; // padding for later use 244}; 245 246// The following must be called first before any use. 247WEBP_EXTERN(void) WebPMemoryWriterInit(WebPMemoryWriter* writer); 248 249// The following must be called to deallocate writer->mem memory. The 'writer' 250// object itself is not deallocated. 251WEBP_EXTERN(void) WebPMemoryWriterClear(WebPMemoryWriter* writer); 252// The custom writer to be used with WebPMemoryWriter as custom_ptr. Upon 253// completion, writer.mem and writer.size will hold the coded data. 254// writer.mem must be freed by calling WebPMemoryWriterClear. 255WEBP_EXTERN(int) WebPMemoryWrite(const uint8_t* data, size_t data_size, 256 const WebPPicture* picture); 257 258// Progress hook, called from time to time to report progress. It can return 259// false to request an abort of the encoding process, or true otherwise if 260// everything is OK. 261typedef int (*WebPProgressHook)(int percent, const WebPPicture* picture); 262 263// Color spaces. 264typedef enum WebPEncCSP { 265 // chroma sampling 266 WEBP_YUV420 = 0, // 4:2:0 267 WEBP_YUV420A = 4, // alpha channel variant 268 WEBP_CSP_UV_MASK = 3, // bit-mask to get the UV sampling factors 269 WEBP_CSP_ALPHA_BIT = 4 // bit that is set if alpha is present 270} WebPEncCSP; 271 272// Encoding error conditions. 273typedef enum WebPEncodingError { 274 VP8_ENC_OK = 0, 275 VP8_ENC_ERROR_OUT_OF_MEMORY, // memory error allocating objects 276 VP8_ENC_ERROR_BITSTREAM_OUT_OF_MEMORY, // memory error while flushing bits 277 VP8_ENC_ERROR_NULL_PARAMETER, // a pointer parameter is NULL 278 VP8_ENC_ERROR_INVALID_CONFIGURATION, // configuration is invalid 279 VP8_ENC_ERROR_BAD_DIMENSION, // picture has invalid width/height 280 VP8_ENC_ERROR_PARTITION0_OVERFLOW, // partition is bigger than 512k 281 VP8_ENC_ERROR_PARTITION_OVERFLOW, // partition is bigger than 16M 282 VP8_ENC_ERROR_BAD_WRITE, // error while flushing bytes 283 VP8_ENC_ERROR_FILE_TOO_BIG, // file is bigger than 4G 284 VP8_ENC_ERROR_USER_ABORT, // abort request by user 285 VP8_ENC_ERROR_LAST // list terminator. always last. 286} WebPEncodingError; 287 288// maximum width/height allowed (inclusive), in pixels 289#define WEBP_MAX_DIMENSION 16383 290 291// Main exchange structure (input samples, output bytes, statistics) 292struct WebPPicture { 293 // INPUT 294 ////////////// 295 // Main flag for encoder selecting between ARGB or YUV input. 296 // It is recommended to use ARGB input (*argb, argb_stride) for lossless 297 // compression, and YUV input (*y, *u, *v, etc.) for lossy compression 298 // since these are the respective native colorspace for these formats. 299 int use_argb; 300 301 // YUV input (mostly used for input to lossy compression) 302 WebPEncCSP colorspace; // colorspace: should be YUV420 for now (=Y'CbCr). 303 int width, height; // dimensions (less or equal to WEBP_MAX_DIMENSION) 304 uint8_t *y, *u, *v; // pointers to luma/chroma planes. 305 int y_stride, uv_stride; // luma/chroma strides. 306 uint8_t* a; // pointer to the alpha plane 307 int a_stride; // stride of the alpha plane 308 uint32_t pad1[2]; // padding for later use 309 310 // ARGB input (mostly used for input to lossless compression) 311 uint32_t* argb; // Pointer to argb (32 bit) plane. 312 int argb_stride; // This is stride in pixels units, not bytes. 313 uint32_t pad2[3]; // padding for later use 314 315 // OUTPUT 316 /////////////// 317 // Byte-emission hook, to store compressed bytes as they are ready. 318 WebPWriterFunction writer; // can be NULL 319 void* custom_ptr; // can be used by the writer. 320 321 // map for extra information (only for lossy compression mode) 322 int extra_info_type; // 1: intra type, 2: segment, 3: quant 323 // 4: intra-16 prediction mode, 324 // 5: chroma prediction mode, 325 // 6: bit cost, 7: distortion 326 uint8_t* extra_info; // if not NULL, points to an array of size 327 // ((width + 15) / 16) * ((height + 15) / 16) that 328 // will be filled with a macroblock map, depending 329 // on extra_info_type. 330 331 // STATS AND REPORTS 332 /////////////////////////// 333 // Pointer to side statistics (updated only if not NULL) 334 WebPAuxStats* stats; 335 336 // Error code for the latest error encountered during encoding 337 WebPEncodingError error_code; 338 339 // If not NULL, report progress during encoding. 340 WebPProgressHook progress_hook; 341 342 void* user_data; // this field is free to be set to any value and 343 // used during callbacks (like progress-report e.g.). 344 345 uint32_t pad3[3]; // padding for later use 346 347 // Unused for now 348 uint8_t *pad4, *pad5; 349 uint32_t pad6[8]; // padding for later use 350 351 // PRIVATE FIELDS 352 //////////////////// 353 void* memory_; // row chunk of memory for yuva planes 354 void* memory_argb_; // and for argb too. 355 void* pad7[2]; // padding for later use 356}; 357 358// Internal, version-checked, entry point 359WEBP_EXTERN(int) WebPPictureInitInternal(WebPPicture*, int); 360 361// Should always be called, to initialize the structure. Returns false in case 362// of version mismatch. WebPPictureInit() must have succeeded before using the 363// 'picture' object. 364// Note that, by default, use_argb is false and colorspace is WEBP_YUV420. 365static WEBP_INLINE int WebPPictureInit(WebPPicture* picture) { 366 return WebPPictureInitInternal(picture, WEBP_ENCODER_ABI_VERSION); 367} 368 369//------------------------------------------------------------------------------ 370// WebPPicture utils 371 372// Convenience allocation / deallocation based on picture->width/height: 373// Allocate y/u/v buffers as per colorspace/width/height specification. 374// Note! This function will free the previous buffer if needed. 375// Returns false in case of memory error. 376WEBP_EXTERN(int) WebPPictureAlloc(WebPPicture* picture); 377 378// Release the memory allocated by WebPPictureAlloc() or WebPPictureImport*(). 379// Note that this function does _not_ free the memory used by the 'picture' 380// object itself. 381// Besides memory (which is reclaimed) all other fields of 'picture' are 382// preserved. 383WEBP_EXTERN(void) WebPPictureFree(WebPPicture* picture); 384 385// Copy the pixels of *src into *dst, using WebPPictureAlloc. Upon return, *dst 386// will fully own the copied pixels (this is not a view). The 'dst' picture need 387// not be initialized as its content is overwritten. 388// Returns false in case of memory allocation error. 389WEBP_EXTERN(int) WebPPictureCopy(const WebPPicture* src, WebPPicture* dst); 390 391// Compute PSNR, SSIM or LSIM distortion metric between two pictures. Results 392// are in dB, stored in result[] in the Y/U/V/Alpha/All or B/G/R/A/All order. 393// Returns false in case of error (src and ref don't have same dimension, ...) 394// Warning: this function is rather CPU-intensive. 395WEBP_EXTERN(int) WebPPictureDistortion( 396 const WebPPicture* src, const WebPPicture* ref, 397 int metric_type, // 0 = PSNR, 1 = SSIM, 2 = LSIM 398 float result[5]); 399 400// self-crops a picture to the rectangle defined by top/left/width/height. 401// Returns false in case of memory allocation error, or if the rectangle is 402// outside of the source picture. 403// The rectangle for the view is defined by the top-left corner pixel 404// coordinates (left, top) as well as its width and height. This rectangle 405// must be fully be comprised inside the 'src' source picture. If the source 406// picture uses the YUV420 colorspace, the top and left coordinates will be 407// snapped to even values. 408WEBP_EXTERN(int) WebPPictureCrop(WebPPicture* picture, 409 int left, int top, int width, int height); 410 411// Extracts a view from 'src' picture into 'dst'. The rectangle for the view 412// is defined by the top-left corner pixel coordinates (left, top) as well 413// as its width and height. This rectangle must be fully be comprised inside 414// the 'src' source picture. If the source picture uses the YUV420 colorspace, 415// the top and left coordinates will be snapped to even values. 416// Picture 'src' must out-live 'dst' picture. Self-extraction of view is allowed 417// ('src' equal to 'dst') as a mean of fast-cropping (but note that doing so, 418// the original dimension will be lost). Picture 'dst' need not be initialized 419// with WebPPictureInit() if it is different from 'src', since its content will 420// be overwritten. 421// Returns false in case of memory allocation error or invalid parameters. 422WEBP_EXTERN(int) WebPPictureView(const WebPPicture* src, 423 int left, int top, int width, int height, 424 WebPPicture* dst); 425 426// Returns true if the 'picture' is actually a view and therefore does 427// not own the memory for pixels. 428WEBP_EXTERN(int) WebPPictureIsView(const WebPPicture* picture); 429 430// Rescale a picture to new dimension width x height. 431// If either 'width' or 'height' (but not both) is 0 the corresponding 432// dimension will be calculated preserving the aspect ratio. 433// No gamma correction is applied. 434// Returns false in case of error (invalid parameter or insufficient memory). 435WEBP_EXTERN(int) WebPPictureRescale(WebPPicture* pic, int width, int height); 436 437// Colorspace conversion function to import RGB samples. 438// Previous buffer will be free'd, if any. 439// *rgb buffer should have a size of at least height * rgb_stride. 440// Returns false in case of memory error. 441WEBP_EXTERN(int) WebPPictureImportRGB( 442 WebPPicture* picture, const uint8_t* rgb, int rgb_stride); 443// Same, but for RGBA buffer. 444WEBP_EXTERN(int) WebPPictureImportRGBA( 445 WebPPicture* picture, const uint8_t* rgba, int rgba_stride); 446// Same, but for RGBA buffer. Imports the RGB direct from the 32-bit format 447// input buffer ignoring the alpha channel. Avoids needing to copy the data 448// to a temporary 24-bit RGB buffer to import the RGB only. 449WEBP_EXTERN(int) WebPPictureImportRGBX( 450 WebPPicture* picture, const uint8_t* rgbx, int rgbx_stride); 451 452// Variants of the above, but taking BGR(A|X) input. 453WEBP_EXTERN(int) WebPPictureImportBGR( 454 WebPPicture* picture, const uint8_t* bgr, int bgr_stride); 455WEBP_EXTERN(int) WebPPictureImportBGRA( 456 WebPPicture* picture, const uint8_t* bgra, int bgra_stride); 457WEBP_EXTERN(int) WebPPictureImportBGRX( 458 WebPPicture* picture, const uint8_t* bgrx, int bgrx_stride); 459 460// Converts picture->argb data to the YUV420A format. The 'colorspace' 461// parameter is deprecated and should be equal to WEBP_YUV420. 462// Upon return, picture->use_argb is set to false. The presence of real 463// non-opaque transparent values is detected, and 'colorspace' will be 464// adjusted accordingly. Note that this method is lossy. 465// Returns false in case of error. 466WEBP_EXTERN(int) WebPPictureARGBToYUVA(WebPPicture* picture, 467 WebPEncCSP /*colorspace = WEBP_YUV420*/); 468 469// Same as WebPPictureARGBToYUVA(), but the conversion is done using 470// pseudo-random dithering with a strength 'dithering' between 471// 0.0 (no dithering) and 1.0 (maximum dithering). This is useful 472// for photographic picture. 473WEBP_EXTERN(int) WebPPictureARGBToYUVADithered( 474 WebPPicture* picture, WebPEncCSP colorspace, float dithering); 475 476// Performs 'smart' RGBA->YUVA420 downsampling and colorspace conversion. 477// Downsampling is handled with extra care in case of color clipping. This 478// method is roughly 2x slower than WebPPictureARGBToYUVA() but produces better 479// YUV representation. 480// Returns false in case of error. 481WEBP_EXTERN(int) WebPPictureSmartARGBToYUVA(WebPPicture* picture); 482 483// Converts picture->yuv to picture->argb and sets picture->use_argb to true. 484// The input format must be YUV_420 or YUV_420A. 485// Note that the use of this method is discouraged if one has access to the 486// raw ARGB samples, since using YUV420 is comparatively lossy. Also, the 487// conversion from YUV420 to ARGB incurs a small loss too. 488// Returns false in case of error. 489WEBP_EXTERN(int) WebPPictureYUVAToARGB(WebPPicture* picture); 490 491// Helper function: given a width x height plane of RGBA or YUV(A) samples 492// clean-up the YUV or RGB samples under fully transparent area, to help 493// compressibility (no guarantee, though). 494WEBP_EXTERN(void) WebPCleanupTransparentArea(WebPPicture* picture); 495 496// Scan the picture 'picture' for the presence of non fully opaque alpha values. 497// Returns true in such case. Otherwise returns false (indicating that the 498// alpha plane can be ignored altogether e.g.). 499WEBP_EXTERN(int) WebPPictureHasTransparency(const WebPPicture* picture); 500 501// Remove the transparency information (if present) by blending the color with 502// the background color 'background_rgb' (specified as 24bit RGB triplet). 503// After this call, all alpha values are reset to 0xff. 504WEBP_EXTERN(void) WebPBlendAlpha(WebPPicture* pic, uint32_t background_rgb); 505 506//------------------------------------------------------------------------------ 507// Main call 508 509// Main encoding call, after config and picture have been initialized. 510// 'picture' must be less than 16384x16384 in dimension (cf WEBP_MAX_DIMENSION), 511// and the 'config' object must be a valid one. 512// Returns false in case of error, true otherwise. 513// In case of error, picture->error_code is updated accordingly. 514// 'picture' can hold the source samples in both YUV(A) or ARGB input, depending 515// on the value of 'picture->use_argb'. It is highly recommended to use 516// the former for lossy encoding, and the latter for lossless encoding 517// (when config.lossless is true). Automatic conversion from one format to 518// another is provided but they both incur some loss. 519WEBP_EXTERN(int) WebPEncode(const WebPConfig* config, WebPPicture* picture); 520 521//------------------------------------------------------------------------------ 522 523#ifdef __cplusplus 524} // extern "C" 525#endif 526 527#endif /* WEBP_WEBP_ENCODE_H_ */ 528