2 /* pngtrans.c - transforms the data in a row (used by both readers and writers)
4 * Last changed in libpng 1.6.9 [February 6, 2014]
5 * Copyright (c) 1998-2014 Glenn Randers-Pehrson
6 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
7 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
9 * This code is released under the libpng license.
10 * For conditions of distribution and use, see the disclaimer
11 * and license in png.h
16 #if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
18 #if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED)
19 /* Turn on BGR-to-RGB mapping */
21 png_set_bgr(png_structrp png_ptr
)
23 png_debug(1, "in png_set_bgr");
28 png_ptr
->transformations
|= PNG_BGR
;
32 #if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)
33 /* Turn on 16 bit byte swapping */
35 png_set_swap(png_structrp png_ptr
)
37 png_debug(1, "in png_set_swap");
42 if (png_ptr
->bit_depth
== 16)
43 png_ptr
->transformations
|= PNG_SWAP_BYTES
;
47 #if defined(PNG_READ_PACK_SUPPORTED) || defined(PNG_WRITE_PACK_SUPPORTED)
48 /* Turn on pixel packing */
50 png_set_packing(png_structrp png_ptr
)
52 png_debug(1, "in png_set_packing");
57 if (png_ptr
->bit_depth
< 8)
59 png_ptr
->transformations
|= PNG_PACK
;
60 # ifdef PNG_WRITE_SUPPORTED
61 png_ptr
->usr_bit_depth
= 8;
67 #if defined(PNG_READ_PACKSWAP_SUPPORTED)||defined(PNG_WRITE_PACKSWAP_SUPPORTED)
68 /* Turn on packed pixel swapping */
70 png_set_packswap(png_structrp png_ptr
)
72 png_debug(1, "in png_set_packswap");
77 if (png_ptr
->bit_depth
< 8)
78 png_ptr
->transformations
|= PNG_PACKSWAP
;
82 #if defined(PNG_READ_SHIFT_SUPPORTED) || defined(PNG_WRITE_SHIFT_SUPPORTED)
84 png_set_shift(png_structrp png_ptr
, png_const_color_8p true_bits
)
86 png_debug(1, "in png_set_shift");
91 png_ptr
->transformations
|= PNG_SHIFT
;
92 png_ptr
->shift
= *true_bits
;
96 #if defined(PNG_READ_INTERLACING_SUPPORTED) || \
97 defined(PNG_WRITE_INTERLACING_SUPPORTED)
99 png_set_interlace_handling(png_structrp png_ptr
)
101 png_debug(1, "in png_set_interlace handling");
103 if (png_ptr
&& png_ptr
->interlaced
)
105 png_ptr
->transformations
|= PNG_INTERLACE
;
113 #if defined(PNG_READ_FILLER_SUPPORTED) || defined(PNG_WRITE_FILLER_SUPPORTED)
114 /* Add a filler byte on read, or remove a filler or alpha byte on write.
115 * The filler type has changed in v0.95 to allow future 2-byte fillers
116 * for 48-bit input data, as well as to avoid problems with some compilers
117 * that don't like bytes as parameters.
120 png_set_filler(png_structrp png_ptr
, png_uint_32 filler
, int filler_loc
)
122 png_debug(1, "in png_set_filler");
127 /* In libpng 1.6 it is possible to determine whether this is a read or write
128 * operation and therefore to do more checking here for a valid call.
130 if (png_ptr
->mode
& PNG_IS_READ_STRUCT
)
132 # ifdef PNG_READ_FILLER_SUPPORTED
133 /* On read png_set_filler is always valid, regardless of the base PNG
134 * format, because other transformations can give a format where the
135 * filler code can execute (basically an 8 or 16-bit component RGB or G
138 * NOTE: usr_channels is not used by the read code! (This has led to
139 * confusion in the past.) The filler is only used in the read code.
141 png_ptr
->filler
= (png_uint_16
)filler
;
143 png_app_error(png_ptr
, "png_set_filler not supported on read");
144 PNG_UNUSED(filler
) /* not used in the write case */
151 # ifdef PNG_WRITE_FILLER_SUPPORTED
152 /* On write the usr_channels parameter must be set correctly at the
153 * start to record the number of channels in the app-supplied data.
155 switch (png_ptr
->color_type
)
157 case PNG_COLOR_TYPE_RGB
:
158 png_ptr
->usr_channels
= 4;
161 case PNG_COLOR_TYPE_GRAY
:
162 if (png_ptr
->bit_depth
>= 8)
164 png_ptr
->usr_channels
= 2;
170 /* There simply isn't any code in libpng to strip out bits
171 * from bytes when the components are less than a byte in
174 png_app_error(png_ptr
,
175 "png_set_filler is invalid for low bit depth gray output");
180 png_app_error(png_ptr
,
181 "png_set_filler: inappropriate color type");
185 png_app_error(png_ptr
, "png_set_filler not supported on write");
190 /* Here on success - libpng supports the operation, set the transformation
191 * and the flag to say where the filler channel is.
193 png_ptr
->transformations
|= PNG_FILLER
;
195 if (filler_loc
== PNG_FILLER_AFTER
)
196 png_ptr
->flags
|= PNG_FLAG_FILLER_AFTER
;
199 png_ptr
->flags
&= ~PNG_FLAG_FILLER_AFTER
;
202 /* Added to libpng-1.2.7 */
204 png_set_add_alpha(png_structrp png_ptr
, png_uint_32 filler
, int filler_loc
)
206 png_debug(1, "in png_set_add_alpha");
211 png_set_filler(png_ptr
, filler
, filler_loc
);
212 /* The above may fail to do anything. */
213 if (png_ptr
->transformations
& PNG_FILLER
)
214 png_ptr
->transformations
|= PNG_ADD_ALPHA
;
219 #if defined(PNG_READ_SWAP_ALPHA_SUPPORTED) || \
220 defined(PNG_WRITE_SWAP_ALPHA_SUPPORTED)
222 png_set_swap_alpha(png_structrp png_ptr
)
224 png_debug(1, "in png_set_swap_alpha");
229 png_ptr
->transformations
|= PNG_SWAP_ALPHA
;
233 #if defined(PNG_READ_INVERT_ALPHA_SUPPORTED) || \
234 defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED)
236 png_set_invert_alpha(png_structrp png_ptr
)
238 png_debug(1, "in png_set_invert_alpha");
243 png_ptr
->transformations
|= PNG_INVERT_ALPHA
;
247 #if defined(PNG_READ_INVERT_SUPPORTED) || defined(PNG_WRITE_INVERT_SUPPORTED)
249 png_set_invert_mono(png_structrp png_ptr
)
251 png_debug(1, "in png_set_invert_mono");
256 png_ptr
->transformations
|= PNG_INVERT_MONO
;
259 /* Invert monochrome grayscale data */
261 png_do_invert(png_row_infop row_info
, png_bytep row
)
263 png_debug(1, "in png_do_invert");
265 /* This test removed from libpng version 1.0.13 and 1.2.0:
266 * if (row_info->bit_depth == 1 &&
268 if (row_info
->color_type
== PNG_COLOR_TYPE_GRAY
)
272 png_size_t istop
= row_info
->rowbytes
;
274 for (i
= 0; i
< istop
; i
++)
276 *rp
= (png_byte
)(~(*rp
));
281 else if (row_info
->color_type
== PNG_COLOR_TYPE_GRAY_ALPHA
&&
282 row_info
->bit_depth
== 8)
286 png_size_t istop
= row_info
->rowbytes
;
288 for (i
= 0; i
< istop
; i
+= 2)
290 *rp
= (png_byte
)(~(*rp
));
295 #ifdef PNG_16BIT_SUPPORTED
296 else if (row_info
->color_type
== PNG_COLOR_TYPE_GRAY_ALPHA
&&
297 row_info
->bit_depth
== 16)
301 png_size_t istop
= row_info
->rowbytes
;
303 for (i
= 0; i
< istop
; i
+= 4)
305 *rp
= (png_byte
)(~(*rp
));
306 *(rp
+ 1) = (png_byte
)(~(*(rp
+ 1)));
314 #ifdef PNG_16BIT_SUPPORTED
315 #if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)
316 /* Swaps byte order on 16 bit depth images */
318 png_do_swap(png_row_infop row_info
, png_bytep row
)
320 png_debug(1, "in png_do_swap");
322 if (row_info
->bit_depth
== 16)
326 png_uint_32 istop
= row_info
->width
* row_info
->channels
;
328 for (i
= 0; i
< istop
; i
++, rp
+= 2)
339 #if defined(PNG_READ_PACKSWAP_SUPPORTED)||defined(PNG_WRITE_PACKSWAP_SUPPORTED)
340 static PNG_CONST png_byte onebppswaptable
[256] = {
341 0x00, 0x80, 0x40, 0xC0, 0x20, 0xA0, 0x60, 0xE0,
342 0x10, 0x90, 0x50, 0xD0, 0x30, 0xB0, 0x70, 0xF0,
343 0x08, 0x88, 0x48, 0xC8, 0x28, 0xA8, 0x68, 0xE8,
344 0x18, 0x98, 0x58, 0xD8, 0x38, 0xB8, 0x78, 0xF8,
345 0x04, 0x84, 0x44, 0xC4, 0x24, 0xA4, 0x64, 0xE4,
346 0x14, 0x94, 0x54, 0xD4, 0x34, 0xB4, 0x74, 0xF4,
347 0x0C, 0x8C, 0x4C, 0xCC, 0x2C, 0xAC, 0x6C, 0xEC,
348 0x1C, 0x9C, 0x5C, 0xDC, 0x3C, 0xBC, 0x7C, 0xFC,
349 0x02, 0x82, 0x42, 0xC2, 0x22, 0xA2, 0x62, 0xE2,
350 0x12, 0x92, 0x52, 0xD2, 0x32, 0xB2, 0x72, 0xF2,
351 0x0A, 0x8A, 0x4A, 0xCA, 0x2A, 0xAA, 0x6A, 0xEA,
352 0x1A, 0x9A, 0x5A, 0xDA, 0x3A, 0xBA, 0x7A, 0xFA,
353 0x06, 0x86, 0x46, 0xC6, 0x26, 0xA6, 0x66, 0xE6,
354 0x16, 0x96, 0x56, 0xD6, 0x36, 0xB6, 0x76, 0xF6,
355 0x0E, 0x8E, 0x4E, 0xCE, 0x2E, 0xAE, 0x6E, 0xEE,
356 0x1E, 0x9E, 0x5E, 0xDE, 0x3E, 0xBE, 0x7E, 0xFE,
357 0x01, 0x81, 0x41, 0xC1, 0x21, 0xA1, 0x61, 0xE1,
358 0x11, 0x91, 0x51, 0xD1, 0x31, 0xB1, 0x71, 0xF1,
359 0x09, 0x89, 0x49, 0xC9, 0x29, 0xA9, 0x69, 0xE9,
360 0x19, 0x99, 0x59, 0xD9, 0x39, 0xB9, 0x79, 0xF9,
361 0x05, 0x85, 0x45, 0xC5, 0x25, 0xA5, 0x65, 0xE5,
362 0x15, 0x95, 0x55, 0xD5, 0x35, 0xB5, 0x75, 0xF5,
363 0x0D, 0x8D, 0x4D, 0xCD, 0x2D, 0xAD, 0x6D, 0xED,
364 0x1D, 0x9D, 0x5D, 0xDD, 0x3D, 0xBD, 0x7D, 0xFD,
365 0x03, 0x83, 0x43, 0xC3, 0x23, 0xA3, 0x63, 0xE3,
366 0x13, 0x93, 0x53, 0xD3, 0x33, 0xB3, 0x73, 0xF3,
367 0x0B, 0x8B, 0x4B, 0xCB, 0x2B, 0xAB, 0x6B, 0xEB,
368 0x1B, 0x9B, 0x5B, 0xDB, 0x3B, 0xBB, 0x7B, 0xFB,
369 0x07, 0x87, 0x47, 0xC7, 0x27, 0xA7, 0x67, 0xE7,
370 0x17, 0x97, 0x57, 0xD7, 0x37, 0xB7, 0x77, 0xF7,
371 0x0F, 0x8F, 0x4F, 0xCF, 0x2F, 0xAF, 0x6F, 0xEF,
372 0x1F, 0x9F, 0x5F, 0xDF, 0x3F, 0xBF, 0x7F, 0xFF
375 static PNG_CONST png_byte twobppswaptable
[256] = {
376 0x00, 0x40, 0x80, 0xC0, 0x10, 0x50, 0x90, 0xD0,
377 0x20, 0x60, 0xA0, 0xE0, 0x30, 0x70, 0xB0, 0xF0,
378 0x04, 0x44, 0x84, 0xC4, 0x14, 0x54, 0x94, 0xD4,
379 0x24, 0x64, 0xA4, 0xE4, 0x34, 0x74, 0xB4, 0xF4,
380 0x08, 0x48, 0x88, 0xC8, 0x18, 0x58, 0x98, 0xD8,
381 0x28, 0x68, 0xA8, 0xE8, 0x38, 0x78, 0xB8, 0xF8,
382 0x0C, 0x4C, 0x8C, 0xCC, 0x1C, 0x5C, 0x9C, 0xDC,
383 0x2C, 0x6C, 0xAC, 0xEC, 0x3C, 0x7C, 0xBC, 0xFC,
384 0x01, 0x41, 0x81, 0xC1, 0x11, 0x51, 0x91, 0xD1,
385 0x21, 0x61, 0xA1, 0xE1, 0x31, 0x71, 0xB1, 0xF1,
386 0x05, 0x45, 0x85, 0xC5, 0x15, 0x55, 0x95, 0xD5,
387 0x25, 0x65, 0xA5, 0xE5, 0x35, 0x75, 0xB5, 0xF5,
388 0x09, 0x49, 0x89, 0xC9, 0x19, 0x59, 0x99, 0xD9,
389 0x29, 0x69, 0xA9, 0xE9, 0x39, 0x79, 0xB9, 0xF9,
390 0x0D, 0x4D, 0x8D, 0xCD, 0x1D, 0x5D, 0x9D, 0xDD,
391 0x2D, 0x6D, 0xAD, 0xED, 0x3D, 0x7D, 0xBD, 0xFD,
392 0x02, 0x42, 0x82, 0xC2, 0x12, 0x52, 0x92, 0xD2,
393 0x22, 0x62, 0xA2, 0xE2, 0x32, 0x72, 0xB2, 0xF2,
394 0x06, 0x46, 0x86, 0xC6, 0x16, 0x56, 0x96, 0xD6,
395 0x26, 0x66, 0xA6, 0xE6, 0x36, 0x76, 0xB6, 0xF6,
396 0x0A, 0x4A, 0x8A, 0xCA, 0x1A, 0x5A, 0x9A, 0xDA,
397 0x2A, 0x6A, 0xAA, 0xEA, 0x3A, 0x7A, 0xBA, 0xFA,
398 0x0E, 0x4E, 0x8E, 0xCE, 0x1E, 0x5E, 0x9E, 0xDE,
399 0x2E, 0x6E, 0xAE, 0xEE, 0x3E, 0x7E, 0xBE, 0xFE,
400 0x03, 0x43, 0x83, 0xC3, 0x13, 0x53, 0x93, 0xD3,
401 0x23, 0x63, 0xA3, 0xE3, 0x33, 0x73, 0xB3, 0xF3,
402 0x07, 0x47, 0x87, 0xC7, 0x17, 0x57, 0x97, 0xD7,
403 0x27, 0x67, 0xA7, 0xE7, 0x37, 0x77, 0xB7, 0xF7,
404 0x0B, 0x4B, 0x8B, 0xCB, 0x1B, 0x5B, 0x9B, 0xDB,
405 0x2B, 0x6B, 0xAB, 0xEB, 0x3B, 0x7B, 0xBB, 0xFB,
406 0x0F, 0x4F, 0x8F, 0xCF, 0x1F, 0x5F, 0x9F, 0xDF,
407 0x2F, 0x6F, 0xAF, 0xEF, 0x3F, 0x7F, 0xBF, 0xFF
410 static PNG_CONST png_byte fourbppswaptable
[256] = {
411 0x00, 0x10, 0x20, 0x30, 0x40, 0x50, 0x60, 0x70,
412 0x80, 0x90, 0xA0, 0xB0, 0xC0, 0xD0, 0xE0, 0xF0,
413 0x01, 0x11, 0x21, 0x31, 0x41, 0x51, 0x61, 0x71,
414 0x81, 0x91, 0xA1, 0xB1, 0xC1, 0xD1, 0xE1, 0xF1,
415 0x02, 0x12, 0x22, 0x32, 0x42, 0x52, 0x62, 0x72,
416 0x82, 0x92, 0xA2, 0xB2, 0xC2, 0xD2, 0xE2, 0xF2,
417 0x03, 0x13, 0x23, 0x33, 0x43, 0x53, 0x63, 0x73,
418 0x83, 0x93, 0xA3, 0xB3, 0xC3, 0xD3, 0xE3, 0xF3,
419 0x04, 0x14, 0x24, 0x34, 0x44, 0x54, 0x64, 0x74,
420 0x84, 0x94, 0xA4, 0xB4, 0xC4, 0xD4, 0xE4, 0xF4,
421 0x05, 0x15, 0x25, 0x35, 0x45, 0x55, 0x65, 0x75,
422 0x85, 0x95, 0xA5, 0xB5, 0xC5, 0xD5, 0xE5, 0xF5,
423 0x06, 0x16, 0x26, 0x36, 0x46, 0x56, 0x66, 0x76,
424 0x86, 0x96, 0xA6, 0xB6, 0xC6, 0xD6, 0xE6, 0xF6,
425 0x07, 0x17, 0x27, 0x37, 0x47, 0x57, 0x67, 0x77,
426 0x87, 0x97, 0xA7, 0xB7, 0xC7, 0xD7, 0xE7, 0xF7,
427 0x08, 0x18, 0x28, 0x38, 0x48, 0x58, 0x68, 0x78,
428 0x88, 0x98, 0xA8, 0xB8, 0xC8, 0xD8, 0xE8, 0xF8,
429 0x09, 0x19, 0x29, 0x39, 0x49, 0x59, 0x69, 0x79,
430 0x89, 0x99, 0xA9, 0xB9, 0xC9, 0xD9, 0xE9, 0xF9,
431 0x0A, 0x1A, 0x2A, 0x3A, 0x4A, 0x5A, 0x6A, 0x7A,
432 0x8A, 0x9A, 0xAA, 0xBA, 0xCA, 0xDA, 0xEA, 0xFA,
433 0x0B, 0x1B, 0x2B, 0x3B, 0x4B, 0x5B, 0x6B, 0x7B,
434 0x8B, 0x9B, 0xAB, 0xBB, 0xCB, 0xDB, 0xEB, 0xFB,
435 0x0C, 0x1C, 0x2C, 0x3C, 0x4C, 0x5C, 0x6C, 0x7C,
436 0x8C, 0x9C, 0xAC, 0xBC, 0xCC, 0xDC, 0xEC, 0xFC,
437 0x0D, 0x1D, 0x2D, 0x3D, 0x4D, 0x5D, 0x6D, 0x7D,
438 0x8D, 0x9D, 0xAD, 0xBD, 0xCD, 0xDD, 0xED, 0xFD,
439 0x0E, 0x1E, 0x2E, 0x3E, 0x4E, 0x5E, 0x6E, 0x7E,
440 0x8E, 0x9E, 0xAE, 0xBE, 0xCE, 0xDE, 0xEE, 0xFE,
441 0x0F, 0x1F, 0x2F, 0x3F, 0x4F, 0x5F, 0x6F, 0x7F,
442 0x8F, 0x9F, 0xAF, 0xBF, 0xCF, 0xDF, 0xEF, 0xFF
445 /* Swaps pixel packing order within bytes */
447 png_do_packswap(png_row_infop row_info
, png_bytep row
)
449 png_debug(1, "in png_do_packswap");
451 if (row_info
->bit_depth
< 8)
454 png_const_bytep end
, table
;
456 end
= row
+ row_info
->rowbytes
;
458 if (row_info
->bit_depth
== 1)
459 table
= onebppswaptable
;
461 else if (row_info
->bit_depth
== 2)
462 table
= twobppswaptable
;
464 else if (row_info
->bit_depth
== 4)
465 table
= fourbppswaptable
;
470 for (rp
= row
; rp
< end
; rp
++)
474 #endif /* PNG_READ_PACKSWAP_SUPPORTED or PNG_WRITE_PACKSWAP_SUPPORTED */
476 #if defined(PNG_WRITE_FILLER_SUPPORTED) || \
477 defined(PNG_READ_STRIP_ALPHA_SUPPORTED)
478 /* Remove a channel - this used to be 'png_do_strip_filler' but it used a
479 * somewhat weird combination of flags to determine what to do. All the calls
480 * to png_do_strip_filler are changed in 1.5.2 to call this instead with the
483 * The routine isn't general - the channel must be the channel at the start or
484 * end (not in the middle) of each pixel.
487 png_do_strip_channel(png_row_infop row_info
, png_bytep row
, int at_start
)
489 png_bytep sp
= row
; /* source pointer */
490 png_bytep dp
= row
; /* destination pointer */
491 png_bytep ep
= row
+ row_info
->rowbytes
; /* One beyond end of row */
493 /* At the start sp will point to the first byte to copy and dp to where
494 * it is copied to. ep always points just beyond the end of the row, so
495 * the loop simply copies (channels-1) channels until sp reaches ep.
497 * at_start: 0 -- convert AG, XG, ARGB, XRGB, AAGG, XXGG, etc.
498 * nonzero -- convert GA, GX, RGBA, RGBX, GGAA, RRGGBBXX, etc.
501 /* GA, GX, XG cases */
502 if (row_info
->channels
== 2)
504 if (row_info
->bit_depth
== 8)
506 if (at_start
) /* Skip initial filler */
508 else /* Skip initial channel and, for sp, the filler */
511 /* For a 1 pixel wide image there is nothing to do */
513 *dp
++ = *sp
, sp
+= 2;
515 row_info
->pixel_depth
= 8;
518 else if (row_info
->bit_depth
== 16)
520 if (at_start
) /* Skip initial filler */
522 else /* Skip initial channel and, for sp, the filler */
526 *dp
++ = *sp
++, *dp
++ = *sp
, sp
+= 3;
528 row_info
->pixel_depth
= 16;
532 return; /* bad bit depth */
534 row_info
->channels
= 1;
536 /* Finally fix the color type if it records an alpha channel */
537 if (row_info
->color_type
== PNG_COLOR_TYPE_GRAY_ALPHA
)
538 row_info
->color_type
= PNG_COLOR_TYPE_GRAY
;
541 /* RGBA, RGBX, XRGB cases */
542 else if (row_info
->channels
== 4)
544 if (row_info
->bit_depth
== 8)
546 if (at_start
) /* Skip initial filler */
548 else /* Skip initial channels and, for sp, the filler */
551 /* Note that the loop adds 3 to dp and 4 to sp each time. */
553 *dp
++ = *sp
++, *dp
++ = *sp
++, *dp
++ = *sp
, sp
+= 2;
555 row_info
->pixel_depth
= 24;
558 else if (row_info
->bit_depth
== 16)
560 if (at_start
) /* Skip initial filler */
562 else /* Skip initial channels and, for sp, the filler */
567 /* Copy 6 bytes, skip 2 */
568 *dp
++ = *sp
++, *dp
++ = *sp
++;
569 *dp
++ = *sp
++, *dp
++ = *sp
++;
570 *dp
++ = *sp
++, *dp
++ = *sp
, sp
+= 3;
573 row_info
->pixel_depth
= 48;
577 return; /* bad bit depth */
579 row_info
->channels
= 3;
581 /* Finally fix the color type if it records an alpha channel */
582 if (row_info
->color_type
== PNG_COLOR_TYPE_RGB_ALPHA
)
583 row_info
->color_type
= PNG_COLOR_TYPE_RGB
;
587 return; /* The filler channel has gone already */
589 /* Fix the rowbytes value. */
590 row_info
->rowbytes
= dp
-row
;
594 #if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED)
595 /* Swaps red and blue bytes within a pixel */
597 png_do_bgr(png_row_infop row_info
, png_bytep row
)
599 png_debug(1, "in png_do_bgr");
601 if ((row_info
->color_type
& PNG_COLOR_MASK_COLOR
))
603 png_uint_32 row_width
= row_info
->width
;
604 if (row_info
->bit_depth
== 8)
606 if (row_info
->color_type
== PNG_COLOR_TYPE_RGB
)
611 for (i
= 0, rp
= row
; i
< row_width
; i
++, rp
+= 3)
619 else if (row_info
->color_type
== PNG_COLOR_TYPE_RGB_ALPHA
)
624 for (i
= 0, rp
= row
; i
< row_width
; i
++, rp
+= 4)
633 #ifdef PNG_16BIT_SUPPORTED
634 else if (row_info
->bit_depth
== 16)
636 if (row_info
->color_type
== PNG_COLOR_TYPE_RGB
)
641 for (i
= 0, rp
= row
; i
< row_width
; i
++, rp
+= 6)
647 *(rp
+ 1) = *(rp
+ 5);
652 else if (row_info
->color_type
== PNG_COLOR_TYPE_RGB_ALPHA
)
657 for (i
= 0, rp
= row
; i
< row_width
; i
++, rp
+= 8)
663 *(rp
+ 1) = *(rp
+ 5);
671 #endif /* PNG_READ_BGR_SUPPORTED or PNG_WRITE_BGR_SUPPORTED */
673 #if defined(PNG_READ_CHECK_FOR_INVALID_INDEX_SUPPORTED) || \
674 defined(PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED)
675 /* Added at libpng-1.5.10 */
677 png_do_check_palette_indexes(png_structrp png_ptr
, png_row_infop row_info
)
679 if (png_ptr
->num_palette
< (1 << row_info
->bit_depth
) &&
680 png_ptr
->num_palette
> 0) /* num_palette can be 0 in MNG files */
682 /* Calculations moved outside switch in an attempt to stop different
683 * compiler warnings. 'padding' is in *bits* within the last byte, it is
684 * an 'int' because pixel_depth becomes an 'int' in the expression below,
685 * and this calculation is used because it avoids warnings that other
686 * forms produced on either GCC or MSVC.
688 int padding
= (-row_info
->pixel_depth
* row_info
->width
) & 7;
689 png_bytep rp
= png_ptr
->row_buf
+ row_info
->rowbytes
;
691 switch (row_info
->bit_depth
)
695 /* in this case, all bytes must be 0 so we don't need
696 * to unpack the pixels except for the rightmost one.
698 for (; rp
> png_ptr
->row_buf
; rp
--)
700 if (*rp
>> padding
!= 0)
701 png_ptr
->num_palette_max
= 1;
710 for (; rp
> png_ptr
->row_buf
; rp
--)
712 int i
= ((*rp
>> padding
) & 0x03);
714 if (i
> png_ptr
->num_palette_max
)
715 png_ptr
->num_palette_max
= i
;
717 i
= (((*rp
>> padding
) >> 2) & 0x03);
719 if (i
> png_ptr
->num_palette_max
)
720 png_ptr
->num_palette_max
= i
;
722 i
= (((*rp
>> padding
) >> 4) & 0x03);
724 if (i
> png_ptr
->num_palette_max
)
725 png_ptr
->num_palette_max
= i
;
727 i
= (((*rp
>> padding
) >> 6) & 0x03);
729 if (i
> png_ptr
->num_palette_max
)
730 png_ptr
->num_palette_max
= i
;
740 for (; rp
> png_ptr
->row_buf
; rp
--)
742 int i
= ((*rp
>> padding
) & 0x0f);
744 if (i
> png_ptr
->num_palette_max
)
745 png_ptr
->num_palette_max
= i
;
747 i
= (((*rp
>> padding
) >> 4) & 0x0f);
749 if (i
> png_ptr
->num_palette_max
)
750 png_ptr
->num_palette_max
= i
;
760 for (; rp
> png_ptr
->row_buf
; rp
--)
762 if (*rp
> png_ptr
->num_palette_max
)
763 png_ptr
->num_palette_max
= (int) *rp
;
774 #endif /* PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED */
776 #if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
777 defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
778 #ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED
780 png_set_user_transform_info(png_structrp png_ptr
, png_voidp
781 user_transform_ptr
, int user_transform_depth
, int user_transform_channels
)
783 png_debug(1, "in png_set_user_transform_info");
788 #ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
789 if ((png_ptr
->mode
& PNG_IS_READ_STRUCT
) != 0 &&
790 (png_ptr
->flags
& PNG_FLAG_ROW_INIT
) != 0)
792 png_app_error(png_ptr
,
793 "info change after png_start_read_image or png_read_update_info");
798 png_ptr
->user_transform_ptr
= user_transform_ptr
;
799 png_ptr
->user_transform_depth
= (png_byte
)user_transform_depth
;
800 png_ptr
->user_transform_channels
= (png_byte
)user_transform_channels
;
804 /* This function returns a pointer to the user_transform_ptr associated with
805 * the user transform functions. The application should free any memory
806 * associated with this pointer before png_write_destroy and png_read_destroy
809 #ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED
811 png_get_user_transform_ptr(png_const_structrp png_ptr
)
816 return png_ptr
->user_transform_ptr
;
820 #ifdef PNG_USER_TRANSFORM_INFO_SUPPORTED
822 png_get_current_row_number(png_const_structrp png_ptr
)
824 /* See the comments in png.h - this is the sub-image row when reading and
828 return png_ptr
->row_number
;
830 return PNG_UINT_32_MAX
; /* help the app not to fail silently */
834 png_get_current_pass_number(png_const_structrp png_ptr
)
837 return png_ptr
->pass
;
838 return 8; /* invalid */
840 #endif /* PNG_USER_TRANSFORM_INFO_SUPPORTED */
841 #endif /* PNG_READ_USER_TRANSFORM_SUPPORTED ||
842 PNG_WRITE_USER_TRANSFORM_SUPPORTED */
843 #endif /* PNG_READ_SUPPORTED || PNG_WRITE_SUPPORTED */