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 |
20 | extern "C" { |
21 | #endif |
22 | |
23 | #define WEBP_ENCODER_ABI_VERSION 0x020f // 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; |
31 | typedef struct WebPConfig WebPConfig; |
32 | typedef struct WebPPicture WebPPicture; // main structure for I/O |
33 | typedef struct WebPAuxStats WebPAuxStats; |
34 | typedef 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. |
38 | WEBP_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). |
49 | WEBP_EXTERN size_t WebPEncodeRGB(const uint8_t* rgb, |
50 | int width, int height, int stride, |
51 | float quality_factor, uint8_t** output); |
52 | WEBP_EXTERN size_t WebPEncodeBGR(const uint8_t* bgr, |
53 | int width, int height, int stride, |
54 | float quality_factor, uint8_t** output); |
55 | WEBP_EXTERN size_t WebPEncodeRGBA(const uint8_t* rgba, |
56 | int width, int height, int stride, |
57 | float quality_factor, uint8_t** output); |
58 | WEBP_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. |
65 | // Note these functions, like the lossy versions, use the library's default |
66 | // settings. For lossless this means 'exact' is disabled. RGB values in |
67 | // transparent areas will be modified to improve compression. To avoid this, |
68 | // use WebPEncode() and set WebPConfig::exact to 1. |
69 | WEBP_EXTERN size_t WebPEncodeLosslessRGB(const uint8_t* rgb, |
70 | int width, int height, int stride, |
71 | uint8_t** output); |
72 | WEBP_EXTERN size_t WebPEncodeLosslessBGR(const uint8_t* bgr, |
73 | int width, int height, int stride, |
74 | uint8_t** output); |
75 | WEBP_EXTERN size_t WebPEncodeLosslessRGBA(const uint8_t* rgba, |
76 | int width, int height, int stride, |
77 | uint8_t** output); |
78 | WEBP_EXTERN size_t WebPEncodeLosslessBGRA(const uint8_t* bgra, |
79 | int width, int height, int stride, |
80 | uint8_t** output); |
81 | |
82 | //------------------------------------------------------------------------------ |
83 | // Coding parameters |
84 | |
85 | // Image characteristics hint for the underlying encoder. |
86 | typedef enum WebPImageHint { |
87 | WEBP_HINT_DEFAULT = 0, // default preset. |
88 | WEBP_HINT_PICTURE, // digital picture, like portrait, inner shot |
89 | WEBP_HINT_PHOTO, // outdoor photograph, with natural lighting |
90 | WEBP_HINT_GRAPH, // Discrete tone image (graph, map-tile etc). |
91 | WEBP_HINT_LAST |
92 | } WebPImageHint; |
93 | |
94 | // Compression parameters. |
95 | struct WebPConfig { |
96 | int lossless; // Lossless encoding (0=lossy(default), 1=lossless). |
97 | float quality; // between 0 and 100. For lossy, 0 gives the smallest |
98 | // size and 100 the largest. For lossless, this |
99 | // parameter is the amount of effort put into the |
100 | // compression: 0 is the fastest but gives larger |
101 | // files compared to the slowest, but best, 100. |
102 | int method; // quality/speed trade-off (0=fast, 6=slower-better) |
103 | |
104 | WebPImageHint image_hint; // Hint for image type (lossless only for now). |
105 | |
106 | int target_size; // if non-zero, set the desired target size in bytes. |
107 | // Takes precedence over the 'compression' parameter. |
108 | float target_PSNR; // if non-zero, specifies the minimal distortion to |
109 | // try to achieve. Takes precedence over target_size. |
110 | int segments; // maximum number of segments to use, in [1..4] |
111 | int sns_strength; // Spatial Noise Shaping. 0=off, 100=maximum. |
112 | int filter_strength; // range: [0 = off .. 100 = strongest] |
113 | int filter_sharpness; // range: [0 = off .. 7 = least sharp] |
114 | int filter_type; // filtering type: 0 = simple, 1 = strong (only used |
115 | // if filter_strength > 0 or autofilter > 0) |
116 | int autofilter; // Auto adjust filter's strength [0 = off, 1 = on] |
117 | int alpha_compression; // Algorithm for encoding the alpha plane (0 = none, |
118 | // 1 = compressed with WebP lossless). Default is 1. |
119 | int alpha_filtering; // Predictive filtering method for alpha plane. |
120 | // 0: none, 1: fast, 2: best. Default if 1. |
121 | int alpha_quality; // Between 0 (smallest size) and 100 (lossless). |
122 | // Default is 100. |
123 | int pass; // number of entropy-analysis passes (in [1..10]). |
124 | |
125 | int show_compressed; // if true, export the compressed picture back. |
126 | // In-loop filtering is not applied. |
127 | int preprocessing; // preprocessing filter: |
128 | // 0=none, 1=segment-smooth, 2=pseudo-random dithering |
129 | int partitions; // log2(number of token partitions) in [0..3]. Default |
130 | // is set to 0 for easier progressive decoding. |
131 | int partition_limit; // quality degradation allowed to fit the 512k limit |
132 | // on prediction modes coding (0: no degradation, |
133 | // 100: maximum possible degradation). |
134 | int emulate_jpeg_size; // If true, compression parameters will be remapped |
135 | // to better match the expected output size from |
136 | // JPEG compression. Generally, the output size will |
137 | // be similar but the degradation will be lower. |
138 | int thread_level; // If non-zero, try and use multi-threaded encoding. |
139 | int low_memory; // If set, reduce memory usage (but increase CPU use). |
140 | |
141 | int near_lossless; // Near lossless encoding [0 = max loss .. 100 = off |
142 | // (default)]. |
143 | int exact; // if non-zero, preserve the exact RGB values under |
144 | // transparent area. Otherwise, discard this invisible |
145 | // RGB information for better compression. The default |
146 | // value is 0. |
147 | |
148 | int use_delta_palette; // reserved for future lossless feature |
149 | int use_sharp_yuv; // if needed, use sharp (and slow) RGB->YUV conversion |
150 | |
151 | uint32_t pad[2]; // padding for later use |
152 | }; |
153 | |
154 | // Enumerate some predefined settings for WebPConfig, depending on the type |
155 | // of source picture. These presets are used when calling WebPConfigPreset(). |
156 | typedef enum WebPPreset { |
157 | WEBP_PRESET_DEFAULT = 0, // default preset. |
158 | WEBP_PRESET_PICTURE, // digital picture, like portrait, inner shot |
159 | WEBP_PRESET_PHOTO, // outdoor photograph, with natural lighting |
160 | WEBP_PRESET_DRAWING, // hand or line drawing, with high-contrast details |
161 | WEBP_PRESET_ICON, // small-sized colorful images |
162 | WEBP_PRESET_TEXT // text-like |
163 | } WebPPreset; |
164 | |
165 | // Internal, version-checked, entry point |
166 | WEBP_EXTERN int WebPConfigInitInternal(WebPConfig*, WebPPreset, float, int); |
167 | |
168 | // Should always be called, to initialize a fresh WebPConfig structure before |
169 | // modification. Returns false in case of version mismatch. WebPConfigInit() |
170 | // must have succeeded before using the 'config' object. |
171 | // Note that the default values are lossless=0 and quality=75. |
172 | static WEBP_INLINE int WebPConfigInit(WebPConfig* config) { |
173 | return WebPConfigInitInternal(config, WEBP_PRESET_DEFAULT, 75.f, |
174 | WEBP_ENCODER_ABI_VERSION); |
175 | } |
176 | |
177 | // This function will initialize the configuration according to a predefined |
178 | // set of parameters (referred to by 'preset') and a given quality factor. |
179 | // This function can be called as a replacement to WebPConfigInit(). Will |
180 | // return false in case of error. |
181 | static WEBP_INLINE int WebPConfigPreset(WebPConfig* config, |
182 | WebPPreset preset, float quality) { |
183 | return WebPConfigInitInternal(config, preset, quality, |
184 | WEBP_ENCODER_ABI_VERSION); |
185 | } |
186 | |
187 | // Activate the lossless compression mode with the desired efficiency level |
188 | // between 0 (fastest, lowest compression) and 9 (slower, best compression). |
189 | // A good default level is '6', providing a fair tradeoff between compression |
190 | // speed and final compressed size. |
191 | // This function will overwrite several fields from config: 'method', 'quality' |
192 | // and 'lossless'. Returns false in case of parameter error. |
193 | WEBP_EXTERN int WebPConfigLosslessPreset(WebPConfig* config, int level); |
194 | |
195 | // Returns true if 'config' is non-NULL and all configuration parameters are |
196 | // within their valid ranges. |
197 | WEBP_EXTERN int WebPValidateConfig(const WebPConfig* config); |
198 | |
199 | //------------------------------------------------------------------------------ |
200 | // Input / Output |
201 | // Structure for storing auxiliary statistics. |
202 | |
203 | struct WebPAuxStats { |
204 | int coded_size; // final size |
205 | |
206 | float PSNR[5]; // peak-signal-to-noise ratio for Y/U/V/All/Alpha |
207 | int block_count[3]; // number of intra4/intra16/skipped macroblocks |
208 | int [2]; // approximate number of bytes spent for header |
209 | // and mode-partition #0 |
210 | int residual_bytes[3][4]; // approximate number of bytes spent for |
211 | // DC/AC/uv coefficients for each (0..3) segments. |
212 | int segment_size[4]; // number of macroblocks in each segments |
213 | int segment_quant[4]; // quantizer values for each segments |
214 | int segment_level[4]; // filtering strength for each segments [0..63] |
215 | |
216 | int alpha_data_size; // size of the transparency data |
217 | int layer_data_size; // size of the enhancement layer data |
218 | |
219 | // lossless encoder statistics |
220 | uint32_t lossless_features; // bit0:predictor bit1:cross-color transform |
221 | // bit2:subtract-green bit3:color indexing |
222 | int histogram_bits; // number of precision bits of histogram |
223 | int transform_bits; // precision bits for transform |
224 | int cache_bits; // number of bits for color cache lookup |
225 | int palette_size; // number of color in palette, if used |
226 | int lossless_size; // final lossless size |
227 | int lossless_hdr_size; // lossless header (transform, huffman etc) size |
228 | int lossless_data_size; // lossless image data size |
229 | |
230 | uint32_t pad[2]; // padding for later use |
231 | }; |
232 | |
233 | // Signature for output function. Should return true if writing was successful. |
234 | // data/data_size is the segment of data to write, and 'picture' is for |
235 | // reference (and so one can make use of picture->custom_ptr). |
236 | typedef int (*WebPWriterFunction)(const uint8_t* data, size_t data_size, |
237 | const WebPPicture* picture); |
238 | |
239 | // WebPMemoryWrite: a special WebPWriterFunction that writes to memory using |
240 | // the following WebPMemoryWriter object (to be set as a custom_ptr). |
241 | struct WebPMemoryWriter { |
242 | uint8_t* mem; // final buffer (of size 'max_size', larger than 'size'). |
243 | size_t size; // final size |
244 | size_t max_size; // total capacity |
245 | uint32_t pad[1]; // padding for later use |
246 | }; |
247 | |
248 | // The following must be called first before any use. |
249 | WEBP_EXTERN void WebPMemoryWriterInit(WebPMemoryWriter* writer); |
250 | |
251 | // The following must be called to deallocate writer->mem memory. The 'writer' |
252 | // object itself is not deallocated. |
253 | WEBP_EXTERN void WebPMemoryWriterClear(WebPMemoryWriter* writer); |
254 | // The custom writer to be used with WebPMemoryWriter as custom_ptr. Upon |
255 | // completion, writer.mem and writer.size will hold the coded data. |
256 | // writer.mem must be freed by calling WebPMemoryWriterClear. |
257 | WEBP_EXTERN int WebPMemoryWrite(const uint8_t* data, size_t data_size, |
258 | const WebPPicture* picture); |
259 | |
260 | // Progress hook, called from time to time to report progress. It can return |
261 | // false to request an abort of the encoding process, or true otherwise if |
262 | // everything is OK. |
263 | typedef int (*WebPProgressHook)(int percent, const WebPPicture* picture); |
264 | |
265 | // Color spaces. |
266 | typedef enum WebPEncCSP { |
267 | // chroma sampling |
268 | WEBP_YUV420 = 0, // 4:2:0 |
269 | WEBP_YUV420A = 4, // alpha channel variant |
270 | WEBP_CSP_UV_MASK = 3, // bit-mask to get the UV sampling factors |
271 | WEBP_CSP_ALPHA_BIT = 4 // bit that is set if alpha is present |
272 | } WebPEncCSP; |
273 | |
274 | // Encoding error conditions. |
275 | typedef enum WebPEncodingError { |
276 | VP8_ENC_OK = 0, |
277 | VP8_ENC_ERROR_OUT_OF_MEMORY, // memory error allocating objects |
278 | VP8_ENC_ERROR_BITSTREAM_OUT_OF_MEMORY, // memory error while flushing bits |
279 | VP8_ENC_ERROR_NULL_PARAMETER, // a pointer parameter is NULL |
280 | VP8_ENC_ERROR_INVALID_CONFIGURATION, // configuration is invalid |
281 | VP8_ENC_ERROR_BAD_DIMENSION, // picture has invalid width/height |
282 | VP8_ENC_ERROR_PARTITION0_OVERFLOW, // partition is bigger than 512k |
283 | VP8_ENC_ERROR_PARTITION_OVERFLOW, // partition is bigger than 16M |
284 | VP8_ENC_ERROR_BAD_WRITE, // error while flushing bytes |
285 | VP8_ENC_ERROR_FILE_TOO_BIG, // file is bigger than 4G |
286 | VP8_ENC_ERROR_USER_ABORT, // abort request by user |
287 | VP8_ENC_ERROR_LAST // list terminator. always last. |
288 | } WebPEncodingError; |
289 | |
290 | // maximum width/height allowed (inclusive), in pixels |
291 | #define WEBP_MAX_DIMENSION 16383 |
292 | |
293 | // Main exchange structure (input samples, output bytes, statistics) |
294 | struct WebPPicture { |
295 | // INPUT |
296 | ////////////// |
297 | // Main flag for encoder selecting between ARGB or YUV input. |
298 | // It is recommended to use ARGB input (*argb, argb_stride) for lossless |
299 | // compression, and YUV input (*y, *u, *v, etc.) for lossy compression |
300 | // since these are the respective native colorspace for these formats. |
301 | int use_argb; |
302 | |
303 | // YUV input (mostly used for input to lossy compression) |
304 | WebPEncCSP colorspace; // colorspace: should be YUV420 for now (=Y'CbCr). |
305 | int width, height; // dimensions (less or equal to WEBP_MAX_DIMENSION) |
306 | uint8_t* y, *u, *v; // pointers to luma/chroma planes. |
307 | int y_stride, uv_stride; // luma/chroma strides. |
308 | uint8_t* a; // pointer to the alpha plane |
309 | int a_stride; // stride of the alpha plane |
310 | uint32_t pad1[2]; // padding for later use |
311 | |
312 | // ARGB input (mostly used for input to lossless compression) |
313 | uint32_t* argb; // Pointer to argb (32 bit) plane. |
314 | int argb_stride; // This is stride in pixels units, not bytes. |
315 | uint32_t pad2[3]; // padding for later use |
316 | |
317 | // OUTPUT |
318 | /////////////// |
319 | // Byte-emission hook, to store compressed bytes as they are ready. |
320 | WebPWriterFunction writer; // can be NULL |
321 | void* custom_ptr; // can be used by the writer. |
322 | |
323 | // map for extra information (only for lossy compression mode) |
324 | int ; // 1: intra type, 2: segment, 3: quant |
325 | // 4: intra-16 prediction mode, |
326 | // 5: chroma prediction mode, |
327 | // 6: bit cost, 7: distortion |
328 | uint8_t* ; // if not NULL, points to an array of size |
329 | // ((width + 15) / 16) * ((height + 15) / 16) that |
330 | // will be filled with a macroblock map, depending |
331 | // on extra_info_type. |
332 | |
333 | // STATS AND REPORTS |
334 | /////////////////////////// |
335 | // Pointer to side statistics (updated only if not NULL) |
336 | WebPAuxStats* stats; |
337 | |
338 | // Error code for the latest error encountered during encoding |
339 | WebPEncodingError error_code; |
340 | |
341 | // If not NULL, report progress during encoding. |
342 | WebPProgressHook progress_hook; |
343 | |
344 | void* user_data; // this field is free to be set to any value and |
345 | // used during callbacks (like progress-report e.g.). |
346 | |
347 | uint32_t pad3[3]; // padding for later use |
348 | |
349 | // Unused for now |
350 | uint8_t* pad4, *pad5; |
351 | uint32_t pad6[8]; // padding for later use |
352 | |
353 | // PRIVATE FIELDS |
354 | //////////////////// |
355 | void* memory_; // row chunk of memory for yuva planes |
356 | void* memory_argb_; // and for argb too. |
357 | void* pad7[2]; // padding for later use |
358 | }; |
359 | |
360 | // Internal, version-checked, entry point |
361 | WEBP_EXTERN int WebPPictureInitInternal(WebPPicture*, int); |
362 | |
363 | // Should always be called, to initialize the structure. Returns false in case |
364 | // of version mismatch. WebPPictureInit() must have succeeded before using the |
365 | // 'picture' object. |
366 | // Note that, by default, use_argb is false and colorspace is WEBP_YUV420. |
367 | static WEBP_INLINE int WebPPictureInit(WebPPicture* picture) { |
368 | return WebPPictureInitInternal(picture, WEBP_ENCODER_ABI_VERSION); |
369 | } |
370 | |
371 | //------------------------------------------------------------------------------ |
372 | // WebPPicture utils |
373 | |
374 | // Convenience allocation / deallocation based on picture->width/height: |
375 | // Allocate y/u/v buffers as per colorspace/width/height specification. |
376 | // Note! This function will free the previous buffer if needed. |
377 | // Returns false in case of memory error. |
378 | WEBP_EXTERN int WebPPictureAlloc(WebPPicture* picture); |
379 | |
380 | // Release the memory allocated by WebPPictureAlloc() or WebPPictureImport*(). |
381 | // Note that this function does _not_ free the memory used by the 'picture' |
382 | // object itself. |
383 | // Besides memory (which is reclaimed) all other fields of 'picture' are |
384 | // preserved. |
385 | WEBP_EXTERN void WebPPictureFree(WebPPicture* picture); |
386 | |
387 | // Copy the pixels of *src into *dst, using WebPPictureAlloc. Upon return, *dst |
388 | // will fully own the copied pixels (this is not a view). The 'dst' picture need |
389 | // not be initialized as its content is overwritten. |
390 | // Returns false in case of memory allocation error. |
391 | WEBP_EXTERN int WebPPictureCopy(const WebPPicture* src, WebPPicture* dst); |
392 | |
393 | // Compute the single distortion for packed planes of samples. |
394 | // 'src' will be compared to 'ref', and the raw distortion stored into |
395 | // '*distortion'. The refined metric (log(MSE), log(1 - ssim),...' will be |
396 | // stored in '*result'. |
397 | // 'x_step' is the horizontal stride (in bytes) between samples. |
398 | // 'src/ref_stride' is the byte distance between rows. |
399 | // Returns false in case of error (bad parameter, memory allocation error, ...). |
400 | WEBP_EXTERN int WebPPlaneDistortion(const uint8_t* src, size_t src_stride, |
401 | const uint8_t* ref, size_t ref_stride, |
402 | int width, int height, |
403 | size_t x_step, |
404 | int type, // 0 = PSNR, 1 = SSIM, 2 = LSIM |
405 | float* distortion, float* result); |
406 | |
407 | // Compute PSNR, SSIM or LSIM distortion metric between two pictures. Results |
408 | // are in dB, stored in result[] in the B/G/R/A/All order. The distortion is |
409 | // always performed using ARGB samples. Hence if the input is YUV(A), the |
410 | // picture will be internally converted to ARGB (just for the measurement). |
411 | // Warning: this function is rather CPU-intensive. |
412 | WEBP_EXTERN int WebPPictureDistortion( |
413 | const WebPPicture* src, const WebPPicture* ref, |
414 | int metric_type, // 0 = PSNR, 1 = SSIM, 2 = LSIM |
415 | float result[5]); |
416 | |
417 | // self-crops a picture to the rectangle defined by top/left/width/height. |
418 | // Returns false in case of memory allocation error, or if the rectangle is |
419 | // outside of the source picture. |
420 | // The rectangle for the view is defined by the top-left corner pixel |
421 | // coordinates (left, top) as well as its width and height. This rectangle |
422 | // must be fully be comprised inside the 'src' source picture. If the source |
423 | // picture uses the YUV420 colorspace, the top and left coordinates will be |
424 | // snapped to even values. |
425 | WEBP_EXTERN int WebPPictureCrop(WebPPicture* picture, |
426 | int left, int top, int width, int height); |
427 | |
428 | // Extracts a view from 'src' picture into 'dst'. The rectangle for the view |
429 | // is defined by the top-left corner pixel coordinates (left, top) as well |
430 | // as its width and height. This rectangle must be fully be comprised inside |
431 | // the 'src' source picture. If the source picture uses the YUV420 colorspace, |
432 | // the top and left coordinates will be snapped to even values. |
433 | // Picture 'src' must out-live 'dst' picture. Self-extraction of view is allowed |
434 | // ('src' equal to 'dst') as a mean of fast-cropping (but note that doing so, |
435 | // the original dimension will be lost). Picture 'dst' need not be initialized |
436 | // with WebPPictureInit() if it is different from 'src', since its content will |
437 | // be overwritten. |
438 | // Returns false in case of memory allocation error or invalid parameters. |
439 | WEBP_EXTERN int WebPPictureView(const WebPPicture* src, |
440 | int left, int top, int width, int height, |
441 | WebPPicture* dst); |
442 | |
443 | // Returns true if the 'picture' is actually a view and therefore does |
444 | // not own the memory for pixels. |
445 | WEBP_EXTERN int WebPPictureIsView(const WebPPicture* picture); |
446 | |
447 | // Rescale a picture to new dimension width x height. |
448 | // If either 'width' or 'height' (but not both) is 0 the corresponding |
449 | // dimension will be calculated preserving the aspect ratio. |
450 | // No gamma correction is applied. |
451 | // Returns false in case of error (invalid parameter or insufficient memory). |
452 | WEBP_EXTERN int WebPPictureRescale(WebPPicture* pic, int width, int height); |
453 | |
454 | // Colorspace conversion function to import RGB samples. |
455 | // Previous buffer will be free'd, if any. |
456 | // *rgb buffer should have a size of at least height * rgb_stride. |
457 | // Returns false in case of memory error. |
458 | WEBP_EXTERN int WebPPictureImportRGB( |
459 | WebPPicture* picture, const uint8_t* rgb, int rgb_stride); |
460 | // Same, but for RGBA buffer. |
461 | WEBP_EXTERN int WebPPictureImportRGBA( |
462 | WebPPicture* picture, const uint8_t* rgba, int rgba_stride); |
463 | // Same, but for RGBA buffer. Imports the RGB direct from the 32-bit format |
464 | // input buffer ignoring the alpha channel. Avoids needing to copy the data |
465 | // to a temporary 24-bit RGB buffer to import the RGB only. |
466 | WEBP_EXTERN int WebPPictureImportRGBX( |
467 | WebPPicture* picture, const uint8_t* rgbx, int rgbx_stride); |
468 | |
469 | // Variants of the above, but taking BGR(A|X) input. |
470 | WEBP_EXTERN int WebPPictureImportBGR( |
471 | WebPPicture* picture, const uint8_t* bgr, int bgr_stride); |
472 | WEBP_EXTERN int WebPPictureImportBGRA( |
473 | WebPPicture* picture, const uint8_t* bgra, int bgra_stride); |
474 | WEBP_EXTERN int WebPPictureImportBGRX( |
475 | WebPPicture* picture, const uint8_t* bgrx, int bgrx_stride); |
476 | |
477 | // Converts picture->argb data to the YUV420A format. The 'colorspace' |
478 | // parameter is deprecated and should be equal to WEBP_YUV420. |
479 | // Upon return, picture->use_argb is set to false. The presence of real |
480 | // non-opaque transparent values is detected, and 'colorspace' will be |
481 | // adjusted accordingly. Note that this method is lossy. |
482 | // Returns false in case of error. |
483 | WEBP_EXTERN int WebPPictureARGBToYUVA(WebPPicture* picture, |
484 | WebPEncCSP /*colorspace = WEBP_YUV420*/); |
485 | |
486 | // Same as WebPPictureARGBToYUVA(), but the conversion is done using |
487 | // pseudo-random dithering with a strength 'dithering' between |
488 | // 0.0 (no dithering) and 1.0 (maximum dithering). This is useful |
489 | // for photographic picture. |
490 | WEBP_EXTERN int WebPPictureARGBToYUVADithered( |
491 | WebPPicture* picture, WebPEncCSP colorspace, float dithering); |
492 | |
493 | // Performs 'sharp' RGBA->YUVA420 downsampling and colorspace conversion. |
494 | // Downsampling is handled with extra care in case of color clipping. This |
495 | // method is roughly 2x slower than WebPPictureARGBToYUVA() but produces better |
496 | // and sharper YUV representation. |
497 | // Returns false in case of error. |
498 | WEBP_EXTERN int WebPPictureSharpARGBToYUVA(WebPPicture* picture); |
499 | // kept for backward compatibility: |
500 | WEBP_EXTERN int WebPPictureSmartARGBToYUVA(WebPPicture* picture); |
501 | |
502 | // Converts picture->yuv to picture->argb and sets picture->use_argb to true. |
503 | // The input format must be YUV_420 or YUV_420A. The conversion from YUV420 to |
504 | // ARGB incurs a small loss too. |
505 | // Note that the use of this colorspace is discouraged if one has access to the |
506 | // raw ARGB samples, since using YUV420 is comparatively lossy. |
507 | // Returns false in case of error. |
508 | WEBP_EXTERN int WebPPictureYUVAToARGB(WebPPicture* picture); |
509 | |
510 | // Helper function: given a width x height plane of RGBA or YUV(A) samples |
511 | // clean-up or smoothen the YUV or RGB samples under fully transparent area, |
512 | // to help compressibility (no guarantee, though). |
513 | WEBP_EXTERN void WebPCleanupTransparentArea(WebPPicture* picture); |
514 | |
515 | // Scan the picture 'picture' for the presence of non fully opaque alpha values. |
516 | // Returns true in such case. Otherwise returns false (indicating that the |
517 | // alpha plane can be ignored altogether e.g.). |
518 | WEBP_EXTERN int WebPPictureHasTransparency(const WebPPicture* picture); |
519 | |
520 | // Remove the transparency information (if present) by blending the color with |
521 | // the background color 'background_rgb' (specified as 24bit RGB triplet). |
522 | // After this call, all alpha values are reset to 0xff. |
523 | WEBP_EXTERN void WebPBlendAlpha(WebPPicture* pic, uint32_t background_rgb); |
524 | |
525 | //------------------------------------------------------------------------------ |
526 | // Main call |
527 | |
528 | // Main encoding call, after config and picture have been initialized. |
529 | // 'picture' must be less than 16384x16384 in dimension (cf WEBP_MAX_DIMENSION), |
530 | // and the 'config' object must be a valid one. |
531 | // Returns false in case of error, true otherwise. |
532 | // In case of error, picture->error_code is updated accordingly. |
533 | // 'picture' can hold the source samples in both YUV(A) or ARGB input, depending |
534 | // on the value of 'picture->use_argb'. It is highly recommended to use |
535 | // the former for lossy encoding, and the latter for lossless encoding |
536 | // (when config.lossless is true). Automatic conversion from one format to |
537 | // another is provided but they both incur some loss. |
538 | WEBP_EXTERN int WebPEncode(const WebPConfig* config, WebPPicture* picture); |
539 | |
540 | //------------------------------------------------------------------------------ |
541 | |
542 | #ifdef __cplusplus |
543 | } // extern "C" |
544 | #endif |
545 | |
546 | #endif // WEBP_WEBP_ENCODE_H_ |
547 | |