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1 /*
2  * jcparam.c
3  *
4  * This file was part of the Independent JPEG Group's software:
5  * Copyright (C) 1991-1998, Thomas G. Lane.
6  * Modified 2003-2008 by Guido Vollbeding.
7  * libjpeg-turbo Modifications:
8  * Copyright (C) 2009-2011, D. R. Commander.
9  * For conditions of distribution and use, see the accompanying README.ijg
10  * file.
11  *
12  * This file contains optional default-setting code for the JPEG compressor.
13  * Applications do not have to use this file, but those that don't use it
14  * must know a lot more about the innards of the JPEG code.
15  */
16 
17 #define JPEG_INTERNALS
18 #include "jinclude.h"
19 #include "jpeglib.h"
20 #include "jstdhuff.c"
21 
22 
23 /*
24  * Quantization table setup routines
25  */
26 
27 GLOBAL(void)
jpeg_add_quant_table(j_compress_ptr cinfo,int which_tbl,const unsigned int * basic_table,int scale_factor,boolean force_baseline)28 jpeg_add_quant_table (j_compress_ptr cinfo, int which_tbl,
29                       const unsigned int *basic_table,
30                       int scale_factor, boolean force_baseline)
31 /* Define a quantization table equal to the basic_table times
32  * a scale factor (given as a percentage).
33  * If force_baseline is TRUE, the computed quantization table entries
34  * are limited to 1..255 for JPEG baseline compatibility.
35  */
36 {
37   JQUANT_TBL **qtblptr;
38   int i;
39   long temp;
40 
41   /* Safety check to ensure start_compress not called yet. */
42   if (cinfo->global_state != CSTATE_START)
43     ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
44 
45   if (which_tbl < 0 || which_tbl >= NUM_QUANT_TBLS)
46     ERREXIT1(cinfo, JERR_DQT_INDEX, which_tbl);
47 
48   qtblptr = & cinfo->quant_tbl_ptrs[which_tbl];
49 
50   if (*qtblptr == NULL)
51     *qtblptr = jpeg_alloc_quant_table((j_common_ptr) cinfo);
52 
53   for (i = 0; i < DCTSIZE2; i++) {
54     temp = ((long) basic_table[i] * scale_factor + 50L) / 100L;
55     /* limit the values to the valid range */
56     if (temp <= 0L) temp = 1L;
57     if (temp > 32767L) temp = 32767L; /* max quantizer needed for 12 bits */
58     if (force_baseline && temp > 255L)
59       temp = 255L;              /* limit to baseline range if requested */
60     (*qtblptr)->quantval[i] = (UINT16) temp;
61   }
62 
63   /* Initialize sent_table FALSE so table will be written to JPEG file. */
64   (*qtblptr)->sent_table = FALSE;
65 }
66 
67 
68 /* These are the sample quantization tables given in JPEG spec section K.1.
69  * The spec says that the values given produce "good" quality, and
70  * when divided by 2, "very good" quality.
71  */
72 static const unsigned int std_luminance_quant_tbl[DCTSIZE2] = {
73   16,  11,  10,  16,  24,  40,  51,  61,
74   12,  12,  14,  19,  26,  58,  60,  55,
75   14,  13,  16,  24,  40,  57,  69,  56,
76   14,  17,  22,  29,  51,  87,  80,  62,
77   18,  22,  37,  56,  68, 109, 103,  77,
78   24,  35,  55,  64,  81, 104, 113,  92,
79   49,  64,  78,  87, 103, 121, 120, 101,
80   72,  92,  95,  98, 112, 100, 103,  99
81 };
82 static const unsigned int std_chrominance_quant_tbl[DCTSIZE2] = {
83   17,  18,  24,  47,  99,  99,  99,  99,
84   18,  21,  26,  66,  99,  99,  99,  99,
85   24,  26,  56,  99,  99,  99,  99,  99,
86   47,  66,  99,  99,  99,  99,  99,  99,
87   99,  99,  99,  99,  99,  99,  99,  99,
88   99,  99,  99,  99,  99,  99,  99,  99,
89   99,  99,  99,  99,  99,  99,  99,  99,
90   99,  99,  99,  99,  99,  99,  99,  99
91 };
92 
93 
94 #if JPEG_LIB_VERSION >= 70
95 GLOBAL(void)
jpeg_default_qtables(j_compress_ptr cinfo,boolean force_baseline)96 jpeg_default_qtables (j_compress_ptr cinfo, boolean force_baseline)
97 /* Set or change the 'quality' (quantization) setting, using default tables
98  * and straight percentage-scaling quality scales.
99  * This entry point allows different scalings for luminance and chrominance.
100  */
101 {
102   /* Set up two quantization tables using the specified scaling */
103   jpeg_add_quant_table(cinfo, 0, std_luminance_quant_tbl,
104                        cinfo->q_scale_factor[0], force_baseline);
105   jpeg_add_quant_table(cinfo, 1, std_chrominance_quant_tbl,
106                        cinfo->q_scale_factor[1], force_baseline);
107 }
108 #endif
109 
110 
111 GLOBAL(void)
jpeg_set_linear_quality(j_compress_ptr cinfo,int scale_factor,boolean force_baseline)112 jpeg_set_linear_quality (j_compress_ptr cinfo, int scale_factor,
113                          boolean force_baseline)
114 /* Set or change the 'quality' (quantization) setting, using default tables
115  * and a straight percentage-scaling quality scale.  In most cases it's better
116  * to use jpeg_set_quality (below); this entry point is provided for
117  * applications that insist on a linear percentage scaling.
118  */
119 {
120   /* Set up two quantization tables using the specified scaling */
121   jpeg_add_quant_table(cinfo, 0, std_luminance_quant_tbl,
122                        scale_factor, force_baseline);
123   jpeg_add_quant_table(cinfo, 1, std_chrominance_quant_tbl,
124                        scale_factor, force_baseline);
125 }
126 
127 
128 GLOBAL(int)
jpeg_quality_scaling(int quality)129 jpeg_quality_scaling (int quality)
130 /* Convert a user-specified quality rating to a percentage scaling factor
131  * for an underlying quantization table, using our recommended scaling curve.
132  * The input 'quality' factor should be 0 (terrible) to 100 (very good).
133  */
134 {
135   /* Safety limit on quality factor.  Convert 0 to 1 to avoid zero divide. */
136   if (quality <= 0) quality = 1;
137   if (quality > 100) quality = 100;
138 
139   /* The basic table is used as-is (scaling 100) for a quality of 50.
140    * Qualities 50..100 are converted to scaling percentage 200 - 2*Q;
141    * note that at Q=100 the scaling is 0, which will cause jpeg_add_quant_table
142    * to make all the table entries 1 (hence, minimum quantization loss).
143    * Qualities 1..50 are converted to scaling percentage 5000/Q.
144    */
145   if (quality < 50)
146     quality = 5000 / quality;
147   else
148     quality = 200 - quality*2;
149 
150   return quality;
151 }
152 
153 
154 GLOBAL(void)
jpeg_set_quality(j_compress_ptr cinfo,int quality,boolean force_baseline)155 jpeg_set_quality (j_compress_ptr cinfo, int quality, boolean force_baseline)
156 /* Set or change the 'quality' (quantization) setting, using default tables.
157  * This is the standard quality-adjusting entry point for typical user
158  * interfaces; only those who want detailed control over quantization tables
159  * would use the preceding three routines directly.
160  */
161 {
162   /* Convert user 0-100 rating to percentage scaling */
163   quality = jpeg_quality_scaling(quality);
164 
165   /* Set up standard quality tables */
166   jpeg_set_linear_quality(cinfo, quality, force_baseline);
167 }
168 
169 
170 /*
171  * Default parameter setup for compression.
172  *
173  * Applications that don't choose to use this routine must do their
174  * own setup of all these parameters.  Alternately, you can call this
175  * to establish defaults and then alter parameters selectively.  This
176  * is the recommended approach since, if we add any new parameters,
177  * your code will still work (they'll be set to reasonable defaults).
178  */
179 
180 GLOBAL(void)
jpeg_set_defaults(j_compress_ptr cinfo)181 jpeg_set_defaults (j_compress_ptr cinfo)
182 {
183   int i;
184 
185   /* Safety check to ensure start_compress not called yet. */
186   if (cinfo->global_state != CSTATE_START)
187     ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
188 
189   /* Allocate comp_info array large enough for maximum component count.
190    * Array is made permanent in case application wants to compress
191    * multiple images at same param settings.
192    */
193   if (cinfo->comp_info == NULL)
194     cinfo->comp_info = (jpeg_component_info *)
195       (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
196                                   MAX_COMPONENTS * sizeof(jpeg_component_info));
197 
198   /* Initialize everything not dependent on the color space */
199 
200 #if JPEG_LIB_VERSION >= 70
201   cinfo->scale_num = 1;         /* 1:1 scaling */
202   cinfo->scale_denom = 1;
203 #endif
204   cinfo->data_precision = BITS_IN_JSAMPLE;
205   /* Set up two quantization tables using default quality of 75 */
206   jpeg_set_quality(cinfo, 75, TRUE);
207   /* Set up two Huffman tables */
208   std_huff_tables((j_common_ptr) cinfo);
209 
210   /* Initialize default arithmetic coding conditioning */
211   for (i = 0; i < NUM_ARITH_TBLS; i++) {
212     cinfo->arith_dc_L[i] = 0;
213     cinfo->arith_dc_U[i] = 1;
214     cinfo->arith_ac_K[i] = 5;
215   }
216 
217   /* Default is no multiple-scan output */
218   cinfo->scan_info = NULL;
219   cinfo->num_scans = 0;
220 
221   /* Expect normal source image, not raw downsampled data */
222   cinfo->raw_data_in = FALSE;
223 
224   /* Use Huffman coding, not arithmetic coding, by default */
225   cinfo->arith_code = FALSE;
226 
227   /* By default, don't do extra passes to optimize entropy coding */
228   cinfo->optimize_coding = FALSE;
229   /* The standard Huffman tables are only valid for 8-bit data precision.
230    * If the precision is higher, force optimization on so that usable
231    * tables will be computed.  This test can be removed if default tables
232    * are supplied that are valid for the desired precision.
233    */
234   if (cinfo->data_precision > 8)
235     cinfo->optimize_coding = TRUE;
236 
237   /* By default, use the simpler non-cosited sampling alignment */
238   cinfo->CCIR601_sampling = FALSE;
239 
240 #if JPEG_LIB_VERSION >= 70
241   /* By default, apply fancy downsampling */
242   cinfo->do_fancy_downsampling = TRUE;
243 #endif
244 
245   /* No input smoothing */
246   cinfo->smoothing_factor = 0;
247 
248   /* DCT algorithm preference */
249   cinfo->dct_method = JDCT_DEFAULT;
250 
251   /* No restart markers */
252   cinfo->restart_interval = 0;
253   cinfo->restart_in_rows = 0;
254 
255   /* Fill in default JFIF marker parameters.  Note that whether the marker
256    * will actually be written is determined by jpeg_set_colorspace.
257    *
258    * By default, the library emits JFIF version code 1.01.
259    * An application that wants to emit JFIF 1.02 extension markers should set
260    * JFIF_minor_version to 2.  We could probably get away with just defaulting
261    * to 1.02, but there may still be some decoders in use that will complain
262    * about that; saying 1.01 should minimize compatibility problems.
263    */
264   cinfo->JFIF_major_version = 1; /* Default JFIF version = 1.01 */
265   cinfo->JFIF_minor_version = 1;
266   cinfo->density_unit = 0;      /* Pixel size is unknown by default */
267   cinfo->X_density = 1;         /* Pixel aspect ratio is square by default */
268   cinfo->Y_density = 1;
269 
270   /* Choose JPEG colorspace based on input space, set defaults accordingly */
271 
272   jpeg_default_colorspace(cinfo);
273 }
274 
275 
276 /*
277  * Select an appropriate JPEG colorspace for in_color_space.
278  */
279 
280 GLOBAL(void)
jpeg_default_colorspace(j_compress_ptr cinfo)281 jpeg_default_colorspace (j_compress_ptr cinfo)
282 {
283   switch (cinfo->in_color_space) {
284   case JCS_GRAYSCALE:
285     jpeg_set_colorspace(cinfo, JCS_GRAYSCALE);
286     break;
287   case JCS_RGB:
288   case JCS_EXT_RGB:
289   case JCS_EXT_RGBX:
290   case JCS_EXT_BGR:
291   case JCS_EXT_BGRX:
292   case JCS_EXT_XBGR:
293   case JCS_EXT_XRGB:
294   case JCS_EXT_RGBA:
295   case JCS_EXT_BGRA:
296   case JCS_EXT_ABGR:
297   case JCS_EXT_ARGB:
298     jpeg_set_colorspace(cinfo, JCS_YCbCr);
299     break;
300   case JCS_YCbCr:
301     jpeg_set_colorspace(cinfo, JCS_YCbCr);
302     break;
303   case JCS_CMYK:
304     jpeg_set_colorspace(cinfo, JCS_CMYK); /* By default, no translation */
305     break;
306   case JCS_YCCK:
307     jpeg_set_colorspace(cinfo, JCS_YCCK);
308     break;
309   case JCS_UNKNOWN:
310     jpeg_set_colorspace(cinfo, JCS_UNKNOWN);
311     break;
312   default:
313     ERREXIT(cinfo, JERR_BAD_IN_COLORSPACE);
314   }
315 }
316 
317 
318 /*
319  * Set the JPEG colorspace, and choose colorspace-dependent default values.
320  */
321 
322 GLOBAL(void)
jpeg_set_colorspace(j_compress_ptr cinfo,J_COLOR_SPACE colorspace)323 jpeg_set_colorspace (j_compress_ptr cinfo, J_COLOR_SPACE colorspace)
324 {
325   jpeg_component_info *compptr;
326   int ci;
327 
328 #define SET_COMP(index,id,hsamp,vsamp,quant,dctbl,actbl)  \
329   (compptr = &cinfo->comp_info[index], \
330    compptr->component_id = (id), \
331    compptr->h_samp_factor = (hsamp), \
332    compptr->v_samp_factor = (vsamp), \
333    compptr->quant_tbl_no = (quant), \
334    compptr->dc_tbl_no = (dctbl), \
335    compptr->ac_tbl_no = (actbl) )
336 
337   /* Safety check to ensure start_compress not called yet. */
338   if (cinfo->global_state != CSTATE_START)
339     ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
340 
341   /* For all colorspaces, we use Q and Huff tables 0 for luminance components,
342    * tables 1 for chrominance components.
343    */
344 
345   cinfo->jpeg_color_space = colorspace;
346 
347   cinfo->write_JFIF_header = FALSE; /* No marker for non-JFIF colorspaces */
348   cinfo->write_Adobe_marker = FALSE; /* write no Adobe marker by default */
349 
350   switch (colorspace) {
351   case JCS_GRAYSCALE:
352     cinfo->write_JFIF_header = TRUE; /* Write a JFIF marker */
353     cinfo->num_components = 1;
354     /* JFIF specifies component ID 1 */
355     SET_COMP(0, 1, 1,1, 0, 0,0);
356     break;
357   case JCS_RGB:
358     cinfo->write_Adobe_marker = TRUE; /* write Adobe marker to flag RGB */
359     cinfo->num_components = 3;
360     SET_COMP(0, 0x52 /* 'R' */, 1,1, 0, 0,0);
361     SET_COMP(1, 0x47 /* 'G' */, 1,1, 0, 0,0);
362     SET_COMP(2, 0x42 /* 'B' */, 1,1, 0, 0,0);
363     break;
364   case JCS_YCbCr:
365     cinfo->write_JFIF_header = TRUE; /* Write a JFIF marker */
366     cinfo->num_components = 3;
367     /* JFIF specifies component IDs 1,2,3 */
368     /* We default to 2x2 subsamples of chrominance */
369     SET_COMP(0, 1, 2,2, 0, 0,0);
370     SET_COMP(1, 2, 1,1, 1, 1,1);
371     SET_COMP(2, 3, 1,1, 1, 1,1);
372     break;
373   case JCS_CMYK:
374     cinfo->write_Adobe_marker = TRUE; /* write Adobe marker to flag CMYK */
375     cinfo->num_components = 4;
376     SET_COMP(0, 0x43 /* 'C' */, 1,1, 0, 0,0);
377     SET_COMP(1, 0x4D /* 'M' */, 1,1, 0, 0,0);
378     SET_COMP(2, 0x59 /* 'Y' */, 1,1, 0, 0,0);
379     SET_COMP(3, 0x4B /* 'K' */, 1,1, 0, 0,0);
380     break;
381   case JCS_YCCK:
382     cinfo->write_Adobe_marker = TRUE; /* write Adobe marker to flag YCCK */
383     cinfo->num_components = 4;
384     SET_COMP(0, 1, 2,2, 0, 0,0);
385     SET_COMP(1, 2, 1,1, 1, 1,1);
386     SET_COMP(2, 3, 1,1, 1, 1,1);
387     SET_COMP(3, 4, 2,2, 0, 0,0);
388     break;
389   case JCS_UNKNOWN:
390     cinfo->num_components = cinfo->input_components;
391     if (cinfo->num_components < 1 || cinfo->num_components > MAX_COMPONENTS)
392       ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->num_components,
393                MAX_COMPONENTS);
394     for (ci = 0; ci < cinfo->num_components; ci++) {
395       SET_COMP(ci, ci, 1,1, 0, 0,0);
396     }
397     break;
398   default:
399     ERREXIT(cinfo, JERR_BAD_J_COLORSPACE);
400   }
401 }
402 
403 
404 #ifdef C_PROGRESSIVE_SUPPORTED
405 
406 LOCAL(jpeg_scan_info *)
fill_a_scan(jpeg_scan_info * scanptr,int ci,int Ss,int Se,int Ah,int Al)407 fill_a_scan (jpeg_scan_info *scanptr, int ci,
408              int Ss, int Se, int Ah, int Al)
409 /* Support routine: generate one scan for specified component */
410 {
411   scanptr->comps_in_scan = 1;
412   scanptr->component_index[0] = ci;
413   scanptr->Ss = Ss;
414   scanptr->Se = Se;
415   scanptr->Ah = Ah;
416   scanptr->Al = Al;
417   scanptr++;
418   return scanptr;
419 }
420 
421 LOCAL(jpeg_scan_info *)
fill_scans(jpeg_scan_info * scanptr,int ncomps,int Ss,int Se,int Ah,int Al)422 fill_scans (jpeg_scan_info *scanptr, int ncomps,
423             int Ss, int Se, int Ah, int Al)
424 /* Support routine: generate one scan for each component */
425 {
426   int ci;
427 
428   for (ci = 0; ci < ncomps; ci++) {
429     scanptr->comps_in_scan = 1;
430     scanptr->component_index[0] = ci;
431     scanptr->Ss = Ss;
432     scanptr->Se = Se;
433     scanptr->Ah = Ah;
434     scanptr->Al = Al;
435     scanptr++;
436   }
437   return scanptr;
438 }
439 
440 LOCAL(jpeg_scan_info *)
fill_dc_scans(jpeg_scan_info * scanptr,int ncomps,int Ah,int Al)441 fill_dc_scans (jpeg_scan_info *scanptr, int ncomps, int Ah, int Al)
442 /* Support routine: generate interleaved DC scan if possible, else N scans */
443 {
444   int ci;
445 
446   if (ncomps <= MAX_COMPS_IN_SCAN) {
447     /* Single interleaved DC scan */
448     scanptr->comps_in_scan = ncomps;
449     for (ci = 0; ci < ncomps; ci++)
450       scanptr->component_index[ci] = ci;
451     scanptr->Ss = scanptr->Se = 0;
452     scanptr->Ah = Ah;
453     scanptr->Al = Al;
454     scanptr++;
455   } else {
456     /* Noninterleaved DC scan for each component */
457     scanptr = fill_scans(scanptr, ncomps, 0, 0, Ah, Al);
458   }
459   return scanptr;
460 }
461 
462 
463 /*
464  * Create a recommended progressive-JPEG script.
465  * cinfo->num_components and cinfo->jpeg_color_space must be correct.
466  */
467 
468 GLOBAL(void)
jpeg_simple_progression(j_compress_ptr cinfo)469 jpeg_simple_progression (j_compress_ptr cinfo)
470 {
471   int ncomps = cinfo->num_components;
472   int nscans;
473   jpeg_scan_info *scanptr;
474 
475   /* Safety check to ensure start_compress not called yet. */
476   if (cinfo->global_state != CSTATE_START)
477     ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
478 
479   /* Figure space needed for script.  Calculation must match code below! */
480   if (ncomps == 3 && cinfo->jpeg_color_space == JCS_YCbCr) {
481     /* Custom script for YCbCr color images. */
482     nscans = 10;
483   } else {
484     /* All-purpose script for other color spaces. */
485     if (ncomps > MAX_COMPS_IN_SCAN)
486       nscans = 6 * ncomps;      /* 2 DC + 4 AC scans per component */
487     else
488       nscans = 2 + 4 * ncomps;  /* 2 DC scans; 4 AC scans per component */
489   }
490 
491   /* Allocate space for script.
492    * We need to put it in the permanent pool in case the application performs
493    * multiple compressions without changing the settings.  To avoid a memory
494    * leak if jpeg_simple_progression is called repeatedly for the same JPEG
495    * object, we try to re-use previously allocated space, and we allocate
496    * enough space to handle YCbCr even if initially asked for grayscale.
497    */
498   if (cinfo->script_space == NULL || cinfo->script_space_size < nscans) {
499     cinfo->script_space_size = MAX(nscans, 10);
500     cinfo->script_space = (jpeg_scan_info *)
501       (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
502                         cinfo->script_space_size * sizeof(jpeg_scan_info));
503   }
504   scanptr = cinfo->script_space;
505   cinfo->scan_info = scanptr;
506   cinfo->num_scans = nscans;
507 
508   if (ncomps == 3 && cinfo->jpeg_color_space == JCS_YCbCr) {
509     /* Custom script for YCbCr color images. */
510     /* Initial DC scan */
511     scanptr = fill_dc_scans(scanptr, ncomps, 0, 1);
512     /* Initial AC scan: get some luma data out in a hurry */
513     scanptr = fill_a_scan(scanptr, 0, 1, 5, 0, 2);
514     /* Chroma data is too small to be worth expending many scans on */
515     scanptr = fill_a_scan(scanptr, 2, 1, 63, 0, 1);
516     scanptr = fill_a_scan(scanptr, 1, 1, 63, 0, 1);
517     /* Complete spectral selection for luma AC */
518     scanptr = fill_a_scan(scanptr, 0, 6, 63, 0, 2);
519     /* Refine next bit of luma AC */
520     scanptr = fill_a_scan(scanptr, 0, 1, 63, 2, 1);
521     /* Finish DC successive approximation */
522     scanptr = fill_dc_scans(scanptr, ncomps, 1, 0);
523     /* Finish AC successive approximation */
524     scanptr = fill_a_scan(scanptr, 2, 1, 63, 1, 0);
525     scanptr = fill_a_scan(scanptr, 1, 1, 63, 1, 0);
526     /* Luma bottom bit comes last since it's usually largest scan */
527     scanptr = fill_a_scan(scanptr, 0, 1, 63, 1, 0);
528   } else {
529     /* All-purpose script for other color spaces. */
530     /* Successive approximation first pass */
531     scanptr = fill_dc_scans(scanptr, ncomps, 0, 1);
532     scanptr = fill_scans(scanptr, ncomps, 1, 5, 0, 2);
533     scanptr = fill_scans(scanptr, ncomps, 6, 63, 0, 2);
534     /* Successive approximation second pass */
535     scanptr = fill_scans(scanptr, ncomps, 1, 63, 2, 1);
536     /* Successive approximation final pass */
537     scanptr = fill_dc_scans(scanptr, ncomps, 1, 0);
538     scanptr = fill_scans(scanptr, ncomps, 1, 63, 1, 0);
539   }
540 }
541 
542 #endif /* C_PROGRESSIVE_SUPPORTED */
543