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jcsample.c
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1 /*
2  * jcsample.c
3  *
4  * Copyright (C) 1991-1994, Thomas G. Lane.
5  * This file is part of the Independent JPEG Group's software.
6  * For conditions of distribution and use, see the accompanying README file.
7  *
8  * This file contains downsampling routines.
9  *
10  * Downsampling input data is counted in "row groups". A row group
11  * is defined to be max_v_samp_factor pixel rows of each component,
12  * from which the downsampler produces v_samp_factor sample rows.
13  * A single row group is processed in each call to the downsampler module.
14  *
15  * The downsampler is responsible for edge-expansion of its output data
16  * to fill an integral number of DCT blocks horizontally. The source buffer
17  * may be modified if it is helpful for this purpose (the source buffer is
18  * allocated wide enough to correspond to the desired output width).
19  * The caller (the prep controller) is responsible for vertical padding.
20  *
21  * The downsampler may request "context rows" by setting need_context_rows
22  * during startup. In this case, the input arrays will contain at least
23  * one row group's worth of pixels above and below the passed-in data;
24  * the caller will create dummy rows at image top and bottom by replicating
25  * the first or last real pixel row.
26  *
27  * An excellent reference for image resampling is
28  * Digital Image Warping, George Wolberg, 1990.
29  * Pub. by IEEE Computer Society Press, Los Alamitos, CA. ISBN 0-8186-8944-7.
30  *
31  * The downsampling algorithm used here is a simple average of the source
32  * pixels covered by the output pixel. The hi-falutin sampling literature
33  * refers to this as a "box filter". In general the characteristics of a box
34  * filter are not very good, but for the specific cases we normally use (1:1
35  * and 2:1 ratios) the box is equivalent to a "triangle filter" which is not
36  * nearly so bad. If you intend to use other sampling ratios, you'd be well
37  * advised to improve this code.
38  *
39  * A simple input-smoothing capability is provided. This is mainly intended
40  * for cleaning up color-dithered GIF input files (if you find it inadequate,
41  * we suggest using an external filtering program such as pnmconvol). When
42  * enabled, each input pixel P is replaced by a weighted sum of itself and its
43  * eight neighbors. P's weight is 1-8*SF and each neighbor's weight is SF,
44  * where SF = (smoothing_factor / 1024).
45  * Currently, smoothing is only supported for 2h2v sampling factors.
46  */
47 
48 #define JPEG_INTERNALS
49 #include "jinclude.h"
50 #include "jpeglib.h"
51 
52 
53 /* Pointer to routine to downsample a single component */
54 typedef JMETHOD(void, downsample1_ptr,
55  (j_compress_ptr cinfo, jpeg_component_info * compptr,
56  JSAMPARRAY input_data, JSAMPARRAY output_data));
57 
58 /* Private subobject */
59 
60 typedef struct {
61  struct jpeg_downsampler pub; /* public fields */
62 
63  /* Downsampling method pointers, one per component */
64  downsample1_ptr methods[MAX_COMPONENTS];
66 
68 
69 
70 /*
71  * Initialize for a downsampling pass.
72  */
73 
74 METHODDEF void
76 {
77  /* no work for now */
78 }
79 
80 
81 /*
82  * Expand a component horizontally from width input_cols to width output_cols,
83  * by duplicating the rightmost samples.
84  */
85 
86 LOCAL void
87 expand_right_edge (JSAMPARRAY image_data, int num_rows,
88  JDIMENSION input_cols, JDIMENSION output_cols)
89 {
90  register JSAMPROW ptr;
91  register JSAMPLE pixval;
92  register int count;
93  int row;
94  int numcols = (int) (output_cols - input_cols);
95 
96  if (numcols > 0) {
97  for (row = 0; row < num_rows; row++) {
98  ptr = image_data[row] + input_cols;
99  pixval = ptr[-1]; /* don't need GETJSAMPLE() here */
100  for (count = numcols; count > 0; count--)
101  *ptr++ = pixval;
102  }
103  }
104 }
105 
106 
107 /*
108  * Do downsampling for a whole row group (all components).
109  *
110  * In this version we simply downsample each component independently.
111  */
112 
113 METHODDEF void
115  JSAMPIMAGE input_buf, JDIMENSION in_row_index,
116  JSAMPIMAGE output_buf, JDIMENSION out_row_group_index)
117 {
118  my_downsample_ptr downsample = (my_downsample_ptr) cinfo->downsample;
119  int ci;
120  jpeg_component_info * compptr;
121  JSAMPARRAY in_ptr, out_ptr;
122 
123  for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
124  ci++, compptr++) {
125  in_ptr = input_buf[ci] + in_row_index;
126  out_ptr = output_buf[ci] + (out_row_group_index * compptr->v_samp_factor);
127  (*downsample->methods[ci]) (cinfo, compptr, in_ptr, out_ptr);
128  }
129 }
130 
131 
132 /*
133  * Downsample pixel values of a single component.
134  * One row group is processed per call.
135  * This version handles arbitrary integral sampling ratios, without smoothing.
136  * Note that this version is not actually used for customary sampling ratios.
137  */
138 
139 METHODDEF void
141  JSAMPARRAY input_data, JSAMPARRAY output_data)
142 {
143  int inrow, outrow, h_expand, v_expand, numpix, numpix2, h, v;
144  JDIMENSION outcol, outcol_h; /* outcol_h == outcol*h_expand */
145  JDIMENSION output_cols = compptr->width_in_blocks * DCTSIZE;
146  JSAMPROW inptr, outptr;
147  INT32 outvalue;
148 
149  h_expand = cinfo->max_h_samp_factor / compptr->h_samp_factor;
150  v_expand = cinfo->max_v_samp_factor / compptr->v_samp_factor;
151  numpix = h_expand * v_expand;
152  numpix2 = numpix/2;
153 
154  /* Expand input data enough to let all the output samples be generated
155  * by the standard loop. Special-casing padded output would be more
156  * efficient.
157  */
158  expand_right_edge(input_data, cinfo->max_v_samp_factor,
159  cinfo->image_width, output_cols * h_expand);
160 
161  inrow = 0;
162  for (outrow = 0; outrow < compptr->v_samp_factor; outrow++) {
163  outptr = output_data[outrow];
164  for (outcol = 0, outcol_h = 0; outcol < output_cols;
165  outcol++, outcol_h += h_expand) {
166  outvalue = 0;
167  for (v = 0; v < v_expand; v++) {
168  inptr = input_data[inrow+v] + outcol_h;
169  for (h = 0; h < h_expand; h++) {
170  outvalue += (INT32) GETJSAMPLE(*inptr++);
171  }
172  }
173  *outptr++ = (JSAMPLE) ((outvalue + numpix2) / numpix);
174  }
175  inrow += v_expand;
176  }
177 }
178 
179 
180 /*
181  * Downsample pixel values of a single component.
182  * This version handles the special case of a full-size component,
183  * without smoothing.
184  */
185 
186 METHODDEF void
188  JSAMPARRAY input_data, JSAMPARRAY output_data)
189 {
190  /* Copy the data */
191  jcopy_sample_rows(input_data, 0, output_data, 0,
192  cinfo->max_v_samp_factor, cinfo->image_width);
193  /* Edge-expand */
194  expand_right_edge(output_data, cinfo->max_v_samp_factor,
195  cinfo->image_width, compptr->width_in_blocks * DCTSIZE);
196 }
197 
198 
199 /*
200  * Downsample pixel values of a single component.
201  * This version handles the common case of 2:1 horizontal and 1:1 vertical,
202  * without smoothing.
203  *
204  * A note about the "bias" calculations: when rounding fractional values to
205  * integer, we do not want to always round 0.5 up to the next integer.
206  * If we did that, we'd introduce a noticeable bias towards larger values.
207  * Instead, this code is arranged so that 0.5 will be rounded up or down at
208  * alternate pixel locations (a simple ordered dither pattern).
209  */
210 
211 METHODDEF void
213  JSAMPARRAY input_data, JSAMPARRAY output_data)
214 {
215  int outrow;
216  JDIMENSION outcol;
217  JDIMENSION output_cols = compptr->width_in_blocks * DCTSIZE;
218  register JSAMPROW inptr, outptr;
219  register int bias;
220 
221  /* Expand input data enough to let all the output samples be generated
222  * by the standard loop. Special-casing padded output would be more
223  * efficient.
224  */
225  expand_right_edge(input_data, cinfo->max_v_samp_factor,
226  cinfo->image_width, output_cols * 2);
227 
228  for (outrow = 0; outrow < compptr->v_samp_factor; outrow++) {
229  outptr = output_data[outrow];
230  inptr = input_data[outrow];
231  bias = 0; /* bias = 0,1,0,1,... for successive samples */
232  for (outcol = 0; outcol < output_cols; outcol++) {
233  *outptr++ = (JSAMPLE) ((GETJSAMPLE(*inptr) + GETJSAMPLE(inptr[1])
234  + bias) >> 1);
235  bias ^= 1; /* 0=>1, 1=>0 */
236  inptr += 2;
237  }
238  }
239 }
240 
241 
242 /*
243  * Downsample pixel values of a single component.
244  * This version handles the standard case of 2:1 horizontal and 2:1 vertical,
245  * without smoothing.
246  */
247 
248 METHODDEF void
250  JSAMPARRAY input_data, JSAMPARRAY output_data)
251 {
252  int inrow, outrow;
253  JDIMENSION outcol;
254  JDIMENSION output_cols = compptr->width_in_blocks * DCTSIZE;
255  register JSAMPROW inptr0, inptr1, outptr;
256  register int bias;
257 
258  /* Expand input data enough to let all the output samples be generated
259  * by the standard loop. Special-casing padded output would be more
260  * efficient.
261  */
262  expand_right_edge(input_data, cinfo->max_v_samp_factor,
263  cinfo->image_width, output_cols * 2);
264 
265  inrow = 0;
266  for (outrow = 0; outrow < compptr->v_samp_factor; outrow++) {
267  outptr = output_data[outrow];
268  inptr0 = input_data[inrow];
269  inptr1 = input_data[inrow+1];
270  bias = 1; /* bias = 1,2,1,2,... for successive samples */
271  for (outcol = 0; outcol < output_cols; outcol++) {
272  *outptr++ = (JSAMPLE) ((GETJSAMPLE(*inptr0) + GETJSAMPLE(inptr0[1]) +
273  GETJSAMPLE(*inptr1) + GETJSAMPLE(inptr1[1])
274  + bias) >> 2);
275  bias ^= 3; /* 1=>2, 2=>1 */
276  inptr0 += 2; inptr1 += 2;
277  }
278  inrow += 2;
279  }
280 }
281 
282 
283 #ifdef INPUT_SMOOTHING_SUPPORTED
284 
285 /*
286  * Downsample pixel values of a single component.
287  * This version handles the standard case of 2:1 horizontal and 2:1 vertical,
288  * with smoothing. One row of context is required.
289  */
290 
291 METHODDEF void
293  JSAMPARRAY input_data, JSAMPARRAY output_data)
294 {
295  int inrow, outrow;
296  JDIMENSION colctr;
297  JDIMENSION output_cols = compptr->width_in_blocks * DCTSIZE;
298  register JSAMPROW inptr0, inptr1, above_ptr, below_ptr, outptr;
299  INT32 membersum, neighsum, memberscale, neighscale;
300 
301  /* Expand input data enough to let all the output samples be generated
302  * by the standard loop. Special-casing padded output would be more
303  * efficient.
304  */
305  expand_right_edge(input_data - 1, cinfo->max_v_samp_factor + 2,
306  cinfo->image_width, output_cols * 2);
307 
308  /* We don't bother to form the individual "smoothed" input pixel values;
309  * we can directly compute the output which is the average of the four
310  * smoothed values. Each of the four member pixels contributes a fraction
311  * (1-8*SF) to its own smoothed image and a fraction SF to each of the three
312  * other smoothed pixels, therefore a total fraction (1-5*SF)/4 to the final
313  * output. The four corner-adjacent neighbor pixels contribute a fraction
314  * SF to just one smoothed pixel, or SF/4 to the final output; while the
315  * eight edge-adjacent neighbors contribute SF to each of two smoothed
316  * pixels, or SF/2 overall. In order to use integer arithmetic, these
317  * factors are scaled by 2^16 = 65536.
318  * Also recall that SF = smoothing_factor / 1024.
319  */
320 
321  memberscale = 16384 - cinfo->smoothing_factor * 80; /* scaled (1-5*SF)/4 */
322  neighscale = cinfo->smoothing_factor * 16; /* scaled SF/4 */
323 
324  inrow = 0;
325  for (outrow = 0; outrow < compptr->v_samp_factor; outrow++) {
326  outptr = output_data[outrow];
327  inptr0 = input_data[inrow];
328  inptr1 = input_data[inrow+1];
329  above_ptr = input_data[inrow-1];
330  below_ptr = input_data[inrow+2];
331 
332  /* Special case for first column: pretend column -1 is same as column 0 */
333  membersum = GETJSAMPLE(*inptr0) + GETJSAMPLE(inptr0[1]) +
334  GETJSAMPLE(*inptr1) + GETJSAMPLE(inptr1[1]);
335  neighsum = GETJSAMPLE(*above_ptr) + GETJSAMPLE(above_ptr[1]) +
336  GETJSAMPLE(*below_ptr) + GETJSAMPLE(below_ptr[1]) +
337  GETJSAMPLE(*inptr0) + GETJSAMPLE(inptr0[2]) +
338  GETJSAMPLE(*inptr1) + GETJSAMPLE(inptr1[2]);
339  neighsum += neighsum;
340  neighsum += GETJSAMPLE(*above_ptr) + GETJSAMPLE(above_ptr[2]) +
341  GETJSAMPLE(*below_ptr) + GETJSAMPLE(below_ptr[2]);
342  membersum = membersum * memberscale + neighsum * neighscale;
343  *outptr++ = (JSAMPLE) ((membersum + 32768) >> 16);
344  inptr0 += 2; inptr1 += 2; above_ptr += 2; below_ptr += 2;
345 
346  for (colctr = output_cols - 2; colctr > 0; colctr--) {
347  /* sum of pixels directly mapped to this output element */
348  membersum = GETJSAMPLE(*inptr0) + GETJSAMPLE(inptr0[1]) +
349  GETJSAMPLE(*inptr1) + GETJSAMPLE(inptr1[1]);
350  /* sum of edge-neighbor pixels */
351  neighsum = GETJSAMPLE(*above_ptr) + GETJSAMPLE(above_ptr[1]) +
352  GETJSAMPLE(*below_ptr) + GETJSAMPLE(below_ptr[1]) +
353  GETJSAMPLE(inptr0[-1]) + GETJSAMPLE(inptr0[2]) +
354  GETJSAMPLE(inptr1[-1]) + GETJSAMPLE(inptr1[2]);
355  /* The edge-neighbors count twice as much as corner-neighbors */
356  neighsum += neighsum;
357  /* Add in the corner-neighbors */
358  neighsum += GETJSAMPLE(above_ptr[-1]) + GETJSAMPLE(above_ptr[2]) +
359  GETJSAMPLE(below_ptr[-1]) + GETJSAMPLE(below_ptr[2]);
360  /* form final output scaled up by 2^16 */
361  membersum = membersum * memberscale + neighsum * neighscale;
362  /* round, descale and output it */
363  *outptr++ = (JSAMPLE) ((membersum + 32768) >> 16);
364  inptr0 += 2; inptr1 += 2; above_ptr += 2; below_ptr += 2;
365  }
366 
367  /* Special case for last column */
368  membersum = GETJSAMPLE(*inptr0) + GETJSAMPLE(inptr0[1]) +
369  GETJSAMPLE(*inptr1) + GETJSAMPLE(inptr1[1]);
370  neighsum = GETJSAMPLE(*above_ptr) + GETJSAMPLE(above_ptr[1]) +
371  GETJSAMPLE(*below_ptr) + GETJSAMPLE(below_ptr[1]) +
372  GETJSAMPLE(inptr0[-1]) + GETJSAMPLE(inptr0[1]) +
373  GETJSAMPLE(inptr1[-1]) + GETJSAMPLE(inptr1[1]);
374  neighsum += neighsum;
375  neighsum += GETJSAMPLE(above_ptr[-1]) + GETJSAMPLE(above_ptr[1]) +
376  GETJSAMPLE(below_ptr[-1]) + GETJSAMPLE(below_ptr[1]);
377  membersum = membersum * memberscale + neighsum * neighscale;
378  *outptr = (JSAMPLE) ((membersum + 32768) >> 16);
379 
380  inrow += 2;
381  }
382 }
383 
384 
385 /*
386  * Downsample pixel values of a single component.
387  * This version handles the special case of a full-size component,
388  * with smoothing. One row of context is required.
389  */
390 
391 METHODDEF void
393  JSAMPARRAY input_data, JSAMPARRAY output_data)
394 {
395  int outrow;
396  JDIMENSION colctr;
397  JDIMENSION output_cols = compptr->width_in_blocks * DCTSIZE;
398  register JSAMPROW inptr, above_ptr, below_ptr, outptr;
399  INT32 membersum, neighsum, memberscale, neighscale;
400  int colsum, lastcolsum, nextcolsum;
401 
402  /* Expand input data enough to let all the output samples be generated
403  * by the standard loop. Special-casing padded output would be more
404  * efficient.
405  */
406  expand_right_edge(input_data - 1, cinfo->max_v_samp_factor + 2,
407  cinfo->image_width, output_cols);
408 
409  /* Each of the eight neighbor pixels contributes a fraction SF to the
410  * smoothed pixel, while the main pixel contributes (1-8*SF). In order
411  * to use integer arithmetic, these factors are multiplied by 2^16 = 65536.
412  * Also recall that SF = smoothing_factor / 1024.
413  */
414 
415  memberscale = 65536L - cinfo->smoothing_factor * 512L; /* scaled 1-8*SF */
416  neighscale = cinfo->smoothing_factor * 64; /* scaled SF */
417 
418  for (outrow = 0; outrow < compptr->v_samp_factor; outrow++) {
419  outptr = output_data[outrow];
420  inptr = input_data[outrow];
421  above_ptr = input_data[outrow-1];
422  below_ptr = input_data[outrow+1];
423 
424  /* Special case for first column */
425  colsum = GETJSAMPLE(*above_ptr++) + GETJSAMPLE(*below_ptr++) +
426  GETJSAMPLE(*inptr);
427  membersum = GETJSAMPLE(*inptr++);
428  nextcolsum = GETJSAMPLE(*above_ptr) + GETJSAMPLE(*below_ptr) +
429  GETJSAMPLE(*inptr);
430  neighsum = colsum + (colsum - membersum) + nextcolsum;
431  membersum = membersum * memberscale + neighsum * neighscale;
432  *outptr++ = (JSAMPLE) ((membersum + 32768) >> 16);
433  lastcolsum = colsum; colsum = nextcolsum;
434 
435  for (colctr = output_cols - 2; colctr > 0; colctr--) {
436  membersum = GETJSAMPLE(*inptr++);
437  above_ptr++; below_ptr++;
438  nextcolsum = GETJSAMPLE(*above_ptr) + GETJSAMPLE(*below_ptr) +
439  GETJSAMPLE(*inptr);
440  neighsum = lastcolsum + (colsum - membersum) + nextcolsum;
441  membersum = membersum * memberscale + neighsum * neighscale;
442  *outptr++ = (JSAMPLE) ((membersum + 32768) >> 16);
443  lastcolsum = colsum; colsum = nextcolsum;
444  }
445 
446  /* Special case for last column */
447  membersum = GETJSAMPLE(*inptr);
448  neighsum = lastcolsum + (colsum - membersum) + colsum;
449  membersum = membersum * memberscale + neighsum * neighscale;
450  *outptr = (JSAMPLE) ((membersum + 32768) >> 16);
451 
452  }
453 }
454 
455 #endif /* INPUT_SMOOTHING_SUPPORTED */
456 
457 
458 /*
459  * Module initialization routine for downsampling.
460  * Note that we must select a routine for each component.
461  */
462 
463 GLOBAL void
465 {
466  my_downsample_ptr downsample;
467  int ci;
468  jpeg_component_info * compptr;
469  boolean smoothok = TRUE;
470 
471  downsample = (my_downsample_ptr)
472  (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
474  cinfo->downsample = (struct jpeg_downsampler *) downsample;
475  downsample->pub.start_pass = start_pass_downsample;
476  downsample->pub.downsample = sep_downsample;
477  downsample->pub.need_context_rows = FALSE;
478 
479  if (cinfo->CCIR601_sampling)
480  ERREXIT(cinfo, JERR_CCIR601_NOTIMPL);
481 
482  /* Verify we can handle the sampling factors, and set up method pointers */
483  for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
484  ci++, compptr++) {
485  if (compptr->h_samp_factor == cinfo->max_h_samp_factor &&
486  compptr->v_samp_factor == cinfo->max_v_samp_factor) {
487 #ifdef INPUT_SMOOTHING_SUPPORTED
488  if (cinfo->smoothing_factor) {
489  downsample->methods[ci] = fullsize_smooth_downsample;
490  downsample->pub.need_context_rows = TRUE;
491  } else
492 #endif
493  downsample->methods[ci] = fullsize_downsample;
494  } else if (compptr->h_samp_factor * 2 == cinfo->max_h_samp_factor &&
495  compptr->v_samp_factor == cinfo->max_v_samp_factor) {
496  smoothok = FALSE;
497  downsample->methods[ci] = h2v1_downsample;
498  } else if (compptr->h_samp_factor * 2 == cinfo->max_h_samp_factor &&
499  compptr->v_samp_factor * 2 == cinfo->max_v_samp_factor) {
500 #ifdef INPUT_SMOOTHING_SUPPORTED
501  if (cinfo->smoothing_factor) {
502  downsample->methods[ci] = h2v2_smooth_downsample;
503  downsample->pub.need_context_rows = TRUE;
504  } else
505 #endif
506  downsample->methods[ci] = h2v2_downsample;
507  } else if ((cinfo->max_h_samp_factor % compptr->h_samp_factor) == 0 &&
508  (cinfo->max_v_samp_factor % compptr->v_samp_factor) == 0) {
509  smoothok = FALSE;
510  downsample->methods[ci] = int_downsample;
511  } else
512  ERREXIT(cinfo, JERR_FRACT_SAMPLE_NOTIMPL);
513  }
514 
515 #ifdef INPUT_SMOOTHING_SUPPORTED
516  if (cinfo->smoothing_factor && !smoothok)
517  TRACEMS(cinfo, 0, JTRC_SMOOTH_NOTIMPL);
518 #endif
519 }
METHODDEF void int_downsample(j_compress_ptr cinfo, jpeg_component_info *compptr, JSAMPARRAY input_data, JSAMPARRAY output_data)
Definition: jcsample.c:140
char JSAMPLE
Definition: jmorecfg.h:64
LOCAL void expand_right_edge(JSAMPARRAY image_data, int num_rows, JDIMENSION input_cols, JDIMENSION output_cols)
Definition: jcsample.c:87
typedef JMETHOD(void, downsample1_ptr,(j_compress_ptr cinfo, jpeg_component_info *compptr, JSAMPARRAY input_data, JSAMPARRAY output_data))
JSAMPLE FAR * JSAMPROW
Definition: jpeglib.h:79
METHODDEF void sep_downsample(j_compress_ptr cinfo, JSAMPIMAGE input_buf, JDIMENSION in_row_index, JSAMPIMAGE output_buf, JDIMENSION out_row_group_index)
Definition: jcsample.c:114
const GLdouble * v
Definition: glext.h:2936
GLOBAL void jcopy_sample_rows(JSAMPARRAY input_array, int source_row, JSAMPARRAY output_array, int dest_row, int num_rows, JDIMENSION num_cols)
Definition: jutils.c:107
struct jpeg_common_struct * j_common_ptr
Definition: jpeglib.h:260
case const int
Definition: Callbacks.cpp:52
#define MAX_COMPONENTS
Definition: jmorecfg.h:35
#define GETJSAMPLE(value)
Definition: jmorecfg.h:68
#define LOCAL
Definition: jmorecfg.h:189
#define ERREXIT(cinfo, code)
Definition: jerror.h:193
#define SIZEOF(object)
Definition: jinclude.h:80
long INT32
Definition: jmorecfg.h:154
JDIMENSION width_in_blocks
Definition: jpeglib.h:151
#define TRACEMS(cinfo, lvl, code)
Definition: jerror.h:240
#define JPOOL_IMAGE
Definition: jpeglib.h:736
METHODDEF void h2v2_smooth_downsample(j_compress_ptr cinfo, jpeg_component_info *compptr, JSAMPARRAY input_data, JSAMPARRAY output_data)
Definition: jcsample.c:292
GLfloat bias
Definition: glext.h:3681
GLuint GLuint GLsizei count
Definition: glext.h:2845
my_downsampler * my_downsample_ptr
Definition: jcsample.c:67
METHODDEF void fullsize_smooth_downsample(j_compress_ptr cinfo, jpeg_component_info *compptr, JSAMPARRAY input_data, JSAMPARRAY output_data)
Definition: jcsample.c:392
Definition: eax4.h:1413
struct jpeg_downsampler * downsample
Definition: jpeglib.h:398
GLOBAL void jinit_downsampler(j_compress_ptr cinfo)
Definition: jcsample.c:464
#define GLOBAL
Definition: jmorecfg.h:190
JSAMPARRAY * JSAMPIMAGE
Definition: jpeglib.h:81
#define METHODDEF
Definition: jmorecfg.h:188
struct jpeg_downsampler pub
Definition: jcsample.c:61
METHODDEF void fullsize_downsample(j_compress_ptr cinfo, jpeg_component_info *compptr, JSAMPARRAY input_data, JSAMPARRAY output_data)
Definition: jcsample.c:187
JSAMPROW * JSAMPARRAY
Definition: jpeglib.h:80
GLenum GLenum GLvoid * row
Definition: glext.h:2866
boolean CCIR601_sampling
Definition: jpeglib.h:322
downsample1_ptr methods[MAX_COMPONENTS]
Definition: jcsample.c:64
#define DCTSIZE
Definition: jpeglib.h:42
#define FALSE
Definition: mprintf.c:70
unsigned int JDIMENSION
Definition: jmorecfg.h:177
#define TRUE
Definition: mprintf.c:69
METHODDEF void start_pass_downsample(j_compress_ptr cinfo)
Definition: jcsample.c:75
METHODDEF void h2v2_downsample(j_compress_ptr cinfo, jpeg_component_info *compptr, JSAMPARRAY input_data, JSAMPARRAY output_data)
Definition: jcsample.c:249
METHODDEF void h2v1_downsample(j_compress_ptr cinfo, jpeg_component_info *compptr, JSAMPARRAY input_data, JSAMPARRAY output_data)
Definition: jcsample.c:212
jpeg_component_info * comp_info
Definition: jpeglib.h:298
boolean need_context_rows
Definition: jpegint.h:98
JDIMENSION image_width
Definition: jpeglib.h:278