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1 pmbaty 1
// Copyright 2011 Google Inc. All Rights Reserved.
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//
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// Use of this source code is governed by a BSD-style license
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// that can be found in the COPYING file in the root of the source
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// tree. An additional intellectual property rights grant can be found
6
// in the file PATENTS. All contributing project authors may
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// be found in the AUTHORS file in the root of the source tree.
8
// -----------------------------------------------------------------------------
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//
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 0x020e    // 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.
8 pmbaty 38
WEBP_EXTERN int WebPGetEncoderVersion(void);
1 pmbaty 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).
8 pmbaty 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,
1 pmbaty 56
                                  int width, int height, int stride,
57
                                  float quality_factor, uint8_t** output);
8 pmbaty 58
WEBP_EXTERN size_t WebPEncodeBGRA(const uint8_t* bgra,
1 pmbaty 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.
8 pmbaty 65
WEBP_EXTERN size_t WebPEncodeLosslessRGB(const uint8_t* rgb,
66
                                         int width, int height, int stride,
67
                                         uint8_t** output);
68
WEBP_EXTERN size_t WebPEncodeLosslessBGR(const uint8_t* bgr,
69
                                         int width, int height, int stride,
70
                                         uint8_t** output);
71
WEBP_EXTERN size_t WebPEncodeLosslessRGBA(const uint8_t* rgba,
1 pmbaty 72
                                          int width, int height, int stride,
73
                                          uint8_t** output);
8 pmbaty 74
WEBP_EXTERN size_t WebPEncodeLosslessBGRA(const uint8_t* bgra,
1 pmbaty 75
                                          int width, int height, int stride,
76
                                          uint8_t** output);
77
 
78
// Releases memory returned by the WebPEncode*() functions above.
8 pmbaty 79
WEBP_EXTERN void WebPFree(void* ptr);
1 pmbaty 80
 
81
//------------------------------------------------------------------------------
82
// Coding parameters
83
 
84
// Image characteristics hint for the underlying encoder.
85
typedef 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.
94
struct WebPConfig {
95
  int lossless;           // Lossless encoding (0=lossy(default), 1=lossless).
8 pmbaty 96
  float quality;          // between 0 and 100. For lossy, 0 gives the smallest
97
                          // size and 100 the largest. For lossless, this
98
                          // parameter is the amount of effort put into the
99
                          // compression: 0 is the fastest but gives larger
100
                          // files compared to the slowest, but best, 100.
1 pmbaty 101
  int method;             // quality/speed trade-off (0=fast, 6=slower-better)
102
 
103
  WebPImageHint image_hint;  // Hint for image type (lossless only for now).
104
 
105
  int target_size;        // if non-zero, set the desired target size in bytes.
106
                          // Takes precedence over the 'compression' parameter.
107
  float target_PSNR;      // if non-zero, specifies the minimal distortion to
108
                          // try to achieve. Takes precedence over target_size.
109
  int segments;           // maximum number of segments to use, in [1..4]
110
  int sns_strength;       // Spatial Noise Shaping. 0=off, 100=maximum.
111
  int filter_strength;    // range: [0 = off .. 100 = strongest]
112
  int filter_sharpness;   // range: [0 = off .. 7 = least sharp]
113
  int filter_type;        // filtering type: 0 = simple, 1 = strong (only used
114
                          // if filter_strength > 0 or autofilter > 0)
115
  int autofilter;         // Auto adjust filter's strength [0 = off, 1 = on]
116
  int alpha_compression;  // Algorithm for encoding the alpha plane (0 = none,
117
                          // 1 = compressed with WebP lossless). Default is 1.
118
  int alpha_filtering;    // Predictive filtering method for alpha plane.
119
                          //  0: none, 1: fast, 2: best. Default if 1.
120
  int alpha_quality;      // Between 0 (smallest size) and 100 (lossless).
121
                          // Default is 100.
122
  int pass;               // number of entropy-analysis passes (in [1..10]).
123
 
124
  int show_compressed;    // if true, export the compressed picture back.
125
                          // In-loop filtering is not applied.
126
  int preprocessing;      // preprocessing filter:
127
                          // 0=none, 1=segment-smooth, 2=pseudo-random dithering
128
  int partitions;         // log2(number of token partitions) in [0..3]. Default
129
                          // is set to 0 for easier progressive decoding.
130
  int partition_limit;    // quality degradation allowed to fit the 512k limit
131
                          // on prediction modes coding (0: no degradation,
132
                          // 100: maximum possible degradation).
133
  int emulate_jpeg_size;  // If true, compression parameters will be remapped
134
                          // to better match the expected output size from
135
                          // JPEG compression. Generally, the output size will
136
                          // be similar but the degradation will be lower.
137
  int thread_level;       // If non-zero, try and use multi-threaded encoding.
138
  int low_memory;         // If set, reduce memory usage (but increase CPU use).
139
 
140
  int near_lossless;      // Near lossless encoding [0 = max loss .. 100 = off
141
                          // (default)].
142
  int exact;              // if non-zero, preserve the exact RGB values under
143
                          // transparent area. Otherwise, discard this invisible
144
                          // RGB information for better compression. The default
145
                          // value is 0.
146
 
147
  int use_delta_palette;  // reserved for future lossless feature
148
  int use_sharp_yuv;      // if needed, use sharp (and slow) RGB->YUV conversion
149
 
150
  uint32_t pad[2];        // padding for later use
151
};
152
 
153
// Enumerate some predefined settings for WebPConfig, depending on the type
154
// of source picture. These presets are used when calling WebPConfigPreset().
155
typedef enum WebPPreset {
156
  WEBP_PRESET_DEFAULT = 0,  // default preset.
157
  WEBP_PRESET_PICTURE,      // digital picture, like portrait, inner shot
158
  WEBP_PRESET_PHOTO,        // outdoor photograph, with natural lighting
159
  WEBP_PRESET_DRAWING,      // hand or line drawing, with high-contrast details
160
  WEBP_PRESET_ICON,         // small-sized colorful images
161
  WEBP_PRESET_TEXT          // text-like
162
} WebPPreset;
163
 
164
// Internal, version-checked, entry point
8 pmbaty 165
WEBP_EXTERN int WebPConfigInitInternal(WebPConfig*, WebPPreset, float, int);
1 pmbaty 166
 
167
// Should always be called, to initialize a fresh WebPConfig structure before
168
// modification. Returns false in case of version mismatch. WebPConfigInit()
169
// must have succeeded before using the 'config' object.
170
// Note that the default values are lossless=0 and quality=75.
171
static WEBP_INLINE int WebPConfigInit(WebPConfig* config) {
172
  return WebPConfigInitInternal(config, WEBP_PRESET_DEFAULT, 75.f,
173
                                WEBP_ENCODER_ABI_VERSION);
174
}
175
 
176
// This function will initialize the configuration according to a predefined
177
// set of parameters (referred to by 'preset') and a given quality factor.
178
// This function can be called as a replacement to WebPConfigInit(). Will
179
// return false in case of error.
180
static WEBP_INLINE int WebPConfigPreset(WebPConfig* config,
181
                                        WebPPreset preset, float quality) {
182
  return WebPConfigInitInternal(config, preset, quality,
183
                                WEBP_ENCODER_ABI_VERSION);
184
}
185
 
186
// Activate the lossless compression mode with the desired efficiency level
187
// between 0 (fastest, lowest compression) and 9 (slower, best compression).
188
// A good default level is '6', providing a fair tradeoff between compression
189
// speed and final compressed size.
190
// This function will overwrite several fields from config: 'method', 'quality'
191
// and 'lossless'. Returns false in case of parameter error.
8 pmbaty 192
WEBP_EXTERN int WebPConfigLosslessPreset(WebPConfig* config, int level);
1 pmbaty 193
 
194
// Returns true if 'config' is non-NULL and all configuration parameters are
195
// within their valid ranges.
8 pmbaty 196
WEBP_EXTERN int WebPValidateConfig(const WebPConfig* config);
1 pmbaty 197
 
198
//------------------------------------------------------------------------------
199
// Input / Output
8 pmbaty 200
// Structure for storing auxiliary statistics.
1 pmbaty 201
 
202
struct WebPAuxStats {
203
  int coded_size;         // final size
204
 
205
  float PSNR[5];          // peak-signal-to-noise ratio for Y/U/V/All/Alpha
206
  int block_count[3];     // number of intra4/intra16/skipped macroblocks
207
  int header_bytes[2];    // approximate number of bytes spent for header
208
                          // and mode-partition #0
209
  int residual_bytes[3][4];  // approximate number of bytes spent for
210
                             // DC/AC/uv coefficients for each (0..3) segments.
211
  int segment_size[4];    // number of macroblocks in each segments
212
  int segment_quant[4];   // quantizer values for each segments
213
  int segment_level[4];   // filtering strength for each segments [0..63]
214
 
215
  int alpha_data_size;    // size of the transparency data
216
  int layer_data_size;    // size of the enhancement layer data
217
 
218
  // lossless encoder statistics
219
  uint32_t lossless_features;  // bit0:predictor bit1:cross-color transform
220
                               // bit2:subtract-green bit3:color indexing
221
  int histogram_bits;          // number of precision bits of histogram
222
  int transform_bits;          // precision bits for transform
223
  int cache_bits;              // number of bits for color cache lookup
224
  int palette_size;            // number of color in palette, if used
225
  int lossless_size;           // final lossless size
226
  int lossless_hdr_size;       // lossless header (transform, huffman etc) size
227
  int lossless_data_size;      // lossless image data size
228
 
229
  uint32_t pad[2];        // padding for later use
230
};
231
 
232
// Signature for output function. Should return true if writing was successful.
233
// data/data_size is the segment of data to write, and 'picture' is for
234
// reference (and so one can make use of picture->custom_ptr).
235
typedef int (*WebPWriterFunction)(const uint8_t* data, size_t data_size,
236
                                  const WebPPicture* picture);
237
 
238
// WebPMemoryWrite: a special WebPWriterFunction that writes to memory using
239
// the following WebPMemoryWriter object (to be set as a custom_ptr).
240
struct WebPMemoryWriter {
241
  uint8_t* mem;       // final buffer (of size 'max_size', larger than 'size').
242
  size_t   size;      // final size
243
  size_t   max_size;  // total capacity
244
  uint32_t pad[1];    // padding for later use
245
};
246
 
247
// The following must be called first before any use.
8 pmbaty 248
WEBP_EXTERN void WebPMemoryWriterInit(WebPMemoryWriter* writer);
1 pmbaty 249
 
250
// The following must be called to deallocate writer->mem memory. The 'writer'
251
// object itself is not deallocated.
8 pmbaty 252
WEBP_EXTERN void WebPMemoryWriterClear(WebPMemoryWriter* writer);
1 pmbaty 253
// The custom writer to be used with WebPMemoryWriter as custom_ptr. Upon
254
// completion, writer.mem and writer.size will hold the coded data.
255
// writer.mem must be freed by calling WebPMemoryWriterClear.
8 pmbaty 256
WEBP_EXTERN int WebPMemoryWrite(const uint8_t* data, size_t data_size,
257
                                const WebPPicture* picture);
1 pmbaty 258
 
259
// Progress hook, called from time to time to report progress. It can return
260
// false to request an abort of the encoding process, or true otherwise if
261
// everything is OK.
262
typedef int (*WebPProgressHook)(int percent, const WebPPicture* picture);
263
 
264
// Color spaces.
265
typedef enum WebPEncCSP {
266
  // chroma sampling
267
  WEBP_YUV420  = 0,        // 4:2:0
268
  WEBP_YUV420A = 4,        // alpha channel variant
269
  WEBP_CSP_UV_MASK = 3,    // bit-mask to get the UV sampling factors
270
  WEBP_CSP_ALPHA_BIT = 4   // bit that is set if alpha is present
271
} WebPEncCSP;
272
 
273
// Encoding error conditions.
274
typedef enum WebPEncodingError {
275
  VP8_ENC_OK = 0,
276
  VP8_ENC_ERROR_OUT_OF_MEMORY,            // memory error allocating objects
277
  VP8_ENC_ERROR_BITSTREAM_OUT_OF_MEMORY,  // memory error while flushing bits
278
  VP8_ENC_ERROR_NULL_PARAMETER,           // a pointer parameter is NULL
279
  VP8_ENC_ERROR_INVALID_CONFIGURATION,    // configuration is invalid
280
  VP8_ENC_ERROR_BAD_DIMENSION,            // picture has invalid width/height
281
  VP8_ENC_ERROR_PARTITION0_OVERFLOW,      // partition is bigger than 512k
282
  VP8_ENC_ERROR_PARTITION_OVERFLOW,       // partition is bigger than 16M
283
  VP8_ENC_ERROR_BAD_WRITE,                // error while flushing bytes
284
  VP8_ENC_ERROR_FILE_TOO_BIG,             // file is bigger than 4G
285
  VP8_ENC_ERROR_USER_ABORT,               // abort request by user
286
  VP8_ENC_ERROR_LAST                      // list terminator. always last.
287
} WebPEncodingError;
288
 
289
// maximum width/height allowed (inclusive), in pixels
290
#define WEBP_MAX_DIMENSION 16383
291
 
292
// Main exchange structure (input samples, output bytes, statistics)
293
struct WebPPicture {
294
  //   INPUT
295
  //////////////
296
  // Main flag for encoder selecting between ARGB or YUV input.
297
  // It is recommended to use ARGB input (*argb, argb_stride) for lossless
298
  // compression, and YUV input (*y, *u, *v, etc.) for lossy compression
299
  // since these are the respective native colorspace for these formats.
300
  int use_argb;
301
 
302
  // YUV input (mostly used for input to lossy compression)
303
  WebPEncCSP colorspace;     // colorspace: should be YUV420 for now (=Y'CbCr).
304
  int width, height;         // dimensions (less or equal to WEBP_MAX_DIMENSION)
305
  uint8_t *y, *u, *v;        // pointers to luma/chroma planes.
306
  int y_stride, uv_stride;   // luma/chroma strides.
307
  uint8_t* a;                // pointer to the alpha plane
308
  int a_stride;              // stride of the alpha plane
309
  uint32_t pad1[2];          // padding for later use
310
 
311
  // ARGB input (mostly used for input to lossless compression)
312
  uint32_t* argb;            // Pointer to argb (32 bit) plane.
313
  int argb_stride;           // This is stride in pixels units, not bytes.
314
  uint32_t pad2[3];          // padding for later use
315
 
316
  //   OUTPUT
317
  ///////////////
318
  // Byte-emission hook, to store compressed bytes as they are ready.
319
  WebPWriterFunction writer;  // can be NULL
320
  void* custom_ptr;           // can be used by the writer.
321
 
322
  // map for extra information (only for lossy compression mode)
323
  int extra_info_type;    // 1: intra type, 2: segment, 3: quant
324
                          // 4: intra-16 prediction mode,
325
                          // 5: chroma prediction mode,
326
                          // 6: bit cost, 7: distortion
327
  uint8_t* extra_info;    // if not NULL, points to an array of size
328
                          // ((width + 15) / 16) * ((height + 15) / 16) that
329
                          // will be filled with a macroblock map, depending
330
                          // on extra_info_type.
331
 
332
  //   STATS AND REPORTS
333
  ///////////////////////////
334
  // Pointer to side statistics (updated only if not NULL)
335
  WebPAuxStats* stats;
336
 
337
  // Error code for the latest error encountered during encoding
338
  WebPEncodingError error_code;
339
 
340
  // If not NULL, report progress during encoding.
341
  WebPProgressHook progress_hook;
342
 
343
  void* user_data;        // this field is free to be set to any value and
344
                          // used during callbacks (like progress-report e.g.).
345
 
346
  uint32_t pad3[3];       // padding for later use
347
 
348
  // Unused for now
349
  uint8_t *pad4, *pad5;
350
  uint32_t pad6[8];       // padding for later use
351
 
352
  // PRIVATE FIELDS
353
  ////////////////////
354
  void* memory_;          // row chunk of memory for yuva planes
355
  void* memory_argb_;     // and for argb too.
356
  void* pad7[2];          // padding for later use
357
};
358
 
359
// Internal, version-checked, entry point
8 pmbaty 360
WEBP_EXTERN int WebPPictureInitInternal(WebPPicture*, int);
1 pmbaty 361
 
362
// Should always be called, to initialize the structure. Returns false in case
363
// of version mismatch. WebPPictureInit() must have succeeded before using the
364
// 'picture' object.
365
// Note that, by default, use_argb is false and colorspace is WEBP_YUV420.
366
static WEBP_INLINE int WebPPictureInit(WebPPicture* picture) {
367
  return WebPPictureInitInternal(picture, WEBP_ENCODER_ABI_VERSION);
368
}
369
 
370
//------------------------------------------------------------------------------
371
// WebPPicture utils
372
 
373
// Convenience allocation / deallocation based on picture->width/height:
374
// Allocate y/u/v buffers as per colorspace/width/height specification.
375
// Note! This function will free the previous buffer if needed.
376
// Returns false in case of memory error.
8 pmbaty 377
WEBP_EXTERN int WebPPictureAlloc(WebPPicture* picture);
1 pmbaty 378
 
379
// Release the memory allocated by WebPPictureAlloc() or WebPPictureImport*().
380
// Note that this function does _not_ free the memory used by the 'picture'
381
// object itself.
382
// Besides memory (which is reclaimed) all other fields of 'picture' are
383
// preserved.
8 pmbaty 384
WEBP_EXTERN void WebPPictureFree(WebPPicture* picture);
1 pmbaty 385
 
386
// Copy the pixels of *src into *dst, using WebPPictureAlloc. Upon return, *dst
387
// will fully own the copied pixels (this is not a view). The 'dst' picture need
388
// not be initialized as its content is overwritten.
389
// Returns false in case of memory allocation error.
8 pmbaty 390
WEBP_EXTERN int WebPPictureCopy(const WebPPicture* src, WebPPicture* dst);
1 pmbaty 391
 
392
// Compute the single distortion for packed planes of samples.
393
// 'src' will be compared to 'ref', and the raw distortion stored into
394
// '*distortion'. The refined metric (log(MSE), log(1 - ssim),...' will be
395
// stored in '*result'.
396
// 'x_step' is the horizontal stride (in bytes) between samples.
397
// 'src/ref_stride' is the byte distance between rows.
398
// Returns false in case of error (bad parameter, memory allocation error, ...).
8 pmbaty 399
WEBP_EXTERN int WebPPlaneDistortion(const uint8_t* src, size_t src_stride,
400
                                    const uint8_t* ref, size_t ref_stride,
401
                                    int width, int height,
402
                                    size_t x_step,
403
                                    int type,   // 0 = PSNR, 1 = SSIM, 2 = LSIM
404
                                    float* distortion, float* result);
1 pmbaty 405
 
406
// Compute PSNR, SSIM or LSIM distortion metric between two pictures. Results
407
// are in dB, stored in result[] in the B/G/R/A/All order. The distortion is
408
// always performed using ARGB samples. Hence if the input is YUV(A), the
409
// picture will be internally converted to ARGB (just for the measurement).
410
// Warning: this function is rather CPU-intensive.
8 pmbaty 411
WEBP_EXTERN int WebPPictureDistortion(
1 pmbaty 412
    const WebPPicture* src, const WebPPicture* ref,
413
    int metric_type,           // 0 = PSNR, 1 = SSIM, 2 = LSIM
414
    float result[5]);
415
 
416
// self-crops a picture to the rectangle defined by top/left/width/height.
417
// Returns false in case of memory allocation error, or if the rectangle is
418
// outside of the source picture.
419
// The rectangle for the view is defined by the top-left corner pixel
420
// coordinates (left, top) as well as its width and height. This rectangle
421
// must be fully be comprised inside the 'src' source picture. If the source
422
// picture uses the YUV420 colorspace, the top and left coordinates will be
423
// snapped to even values.
8 pmbaty 424
WEBP_EXTERN int WebPPictureCrop(WebPPicture* picture,
425
                                int left, int top, int width, int height);
1 pmbaty 426
 
427
// Extracts a view from 'src' picture into 'dst'. The rectangle for the view
428
// is defined by the top-left corner pixel coordinates (left, top) as well
429
// as its width and height. This rectangle must be fully be comprised inside
430
// the 'src' source picture. If the source picture uses the YUV420 colorspace,
431
// the top and left coordinates will be snapped to even values.
432
// Picture 'src' must out-live 'dst' picture. Self-extraction of view is allowed
433
// ('src' equal to 'dst') as a mean of fast-cropping (but note that doing so,
434
// the original dimension will be lost). Picture 'dst' need not be initialized
435
// with WebPPictureInit() if it is different from 'src', since its content will
436
// be overwritten.
437
// Returns false in case of memory allocation error or invalid parameters.
8 pmbaty 438
WEBP_EXTERN int WebPPictureView(const WebPPicture* src,
439
                                int left, int top, int width, int height,
440
                                WebPPicture* dst);
1 pmbaty 441
 
442
// Returns true if the 'picture' is actually a view and therefore does
443
// not own the memory for pixels.
8 pmbaty 444
WEBP_EXTERN int WebPPictureIsView(const WebPPicture* picture);
1 pmbaty 445
 
446
// Rescale a picture to new dimension width x height.
447
// If either 'width' or 'height' (but not both) is 0 the corresponding
448
// dimension will be calculated preserving the aspect ratio.
449
// No gamma correction is applied.
450
// Returns false in case of error (invalid parameter or insufficient memory).
8 pmbaty 451
WEBP_EXTERN int WebPPictureRescale(WebPPicture* pic, int width, int height);
1 pmbaty 452
 
453
// Colorspace conversion function to import RGB samples.
454
// Previous buffer will be free'd, if any.
455
// *rgb buffer should have a size of at least height * rgb_stride.
456
// Returns false in case of memory error.
8 pmbaty 457
WEBP_EXTERN int WebPPictureImportRGB(
1 pmbaty 458
    WebPPicture* picture, const uint8_t* rgb, int rgb_stride);
459
// Same, but for RGBA buffer.
8 pmbaty 460
WEBP_EXTERN int WebPPictureImportRGBA(
1 pmbaty 461
    WebPPicture* picture, const uint8_t* rgba, int rgba_stride);
462
// Same, but for RGBA buffer. Imports the RGB direct from the 32-bit format
463
// input buffer ignoring the alpha channel. Avoids needing to copy the data
464
// to a temporary 24-bit RGB buffer to import the RGB only.
8 pmbaty 465
WEBP_EXTERN int WebPPictureImportRGBX(
1 pmbaty 466
    WebPPicture* picture, const uint8_t* rgbx, int rgbx_stride);
467
 
468
// Variants of the above, but taking BGR(A|X) input.
8 pmbaty 469
WEBP_EXTERN int WebPPictureImportBGR(
1 pmbaty 470
    WebPPicture* picture, const uint8_t* bgr, int bgr_stride);
8 pmbaty 471
WEBP_EXTERN int WebPPictureImportBGRA(
1 pmbaty 472
    WebPPicture* picture, const uint8_t* bgra, int bgra_stride);
8 pmbaty 473
WEBP_EXTERN int WebPPictureImportBGRX(
1 pmbaty 474
    WebPPicture* picture, const uint8_t* bgrx, int bgrx_stride);
475
 
476
// Converts picture->argb data to the YUV420A format. The 'colorspace'
477
// parameter is deprecated and should be equal to WEBP_YUV420.
478
// Upon return, picture->use_argb is set to false. The presence of real
479
// non-opaque transparent values is detected, and 'colorspace' will be
480
// adjusted accordingly. Note that this method is lossy.
481
// Returns false in case of error.
8 pmbaty 482
WEBP_EXTERN int WebPPictureARGBToYUVA(WebPPicture* picture,
483
                                      WebPEncCSP /*colorspace = WEBP_YUV420*/);
1 pmbaty 484
 
485
// Same as WebPPictureARGBToYUVA(), but the conversion is done using
486
// pseudo-random dithering with a strength 'dithering' between
487
// 0.0 (no dithering) and 1.0 (maximum dithering). This is useful
488
// for photographic picture.
8 pmbaty 489
WEBP_EXTERN int WebPPictureARGBToYUVADithered(
1 pmbaty 490
    WebPPicture* picture, WebPEncCSP colorspace, float dithering);
491
 
492
// Performs 'sharp' RGBA->YUVA420 downsampling and colorspace conversion.
493
// Downsampling is handled with extra care in case of color clipping. This
494
// method is roughly 2x slower than WebPPictureARGBToYUVA() but produces better
495
// and sharper YUV representation.
496
// Returns false in case of error.
8 pmbaty 497
WEBP_EXTERN int WebPPictureSharpARGBToYUVA(WebPPicture* picture);
1 pmbaty 498
// kept for backward compatibility:
8 pmbaty 499
WEBP_EXTERN int WebPPictureSmartARGBToYUVA(WebPPicture* picture);
1 pmbaty 500
 
501
// Converts picture->yuv to picture->argb and sets picture->use_argb to true.
502
// The input format must be YUV_420 or YUV_420A. The conversion from YUV420 to
503
// ARGB incurs a small loss too.
504
// Note that the use of this colorspace is discouraged if one has access to the
505
// raw ARGB samples, since using YUV420 is comparatively lossy.
506
// Returns false in case of error.
8 pmbaty 507
WEBP_EXTERN int WebPPictureYUVAToARGB(WebPPicture* picture);
1 pmbaty 508
 
509
// Helper function: given a width x height plane of RGBA or YUV(A) samples
8 pmbaty 510
// clean-up or smoothen the YUV or RGB samples under fully transparent area,
511
// to help compressibility (no guarantee, though).
512
WEBP_EXTERN void WebPCleanupTransparentArea(WebPPicture* picture);
1 pmbaty 513
 
514
// Scan the picture 'picture' for the presence of non fully opaque alpha values.
515
// Returns true in such case. Otherwise returns false (indicating that the
516
// alpha plane can be ignored altogether e.g.).
8 pmbaty 517
WEBP_EXTERN int WebPPictureHasTransparency(const WebPPicture* picture);
1 pmbaty 518
 
519
// Remove the transparency information (if present) by blending the color with
520
// the background color 'background_rgb' (specified as 24bit RGB triplet).
521
// After this call, all alpha values are reset to 0xff.
8 pmbaty 522
WEBP_EXTERN void WebPBlendAlpha(WebPPicture* pic, uint32_t background_rgb);
1 pmbaty 523
 
524
//------------------------------------------------------------------------------
525
// Main call
526
 
527
// Main encoding call, after config and picture have been initialized.
528
// 'picture' must be less than 16384x16384 in dimension (cf WEBP_MAX_DIMENSION),
529
// and the 'config' object must be a valid one.
530
// Returns false in case of error, true otherwise.
531
// In case of error, picture->error_code is updated accordingly.
532
// 'picture' can hold the source samples in both YUV(A) or ARGB input, depending
533
// on the value of 'picture->use_argb'. It is highly recommended to use
534
// the former for lossy encoding, and the latter for lossless encoding
535
// (when config.lossless is true). Automatic conversion from one format to
536
// another is provided but they both incur some loss.
8 pmbaty 537
WEBP_EXTERN int WebPEncode(const WebPConfig* config, WebPPicture* picture);
1 pmbaty 538
 
539
//------------------------------------------------------------------------------
540
 
541
#ifdef __cplusplus
542
}    // extern "C"
543
#endif
544
 
545
#endif  /* WEBP_WEBP_ENCODE_H_ */