12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13 * version 2 for more details (a copy is included in the LICENSE file that
14 * accompanied this code).
15 *
16 * You should have received a copy of the GNU General Public License version
17 * 2 along with this work; if not, write to the Free Software Foundation,
18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19 *
20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21 * or visit www.oracle.com if you need additional information or have any
22 * questions.
23 */
24
25 /* pngrtran.c - transforms the data in a row for PNG readers
26 *
27 * This file is available under and governed by the GNU General Public
28 * License version 2 only, as published by the Free Software Foundation.
29 * However, the following notice accompanied the original version of this
30 * file and, per its terms, should not be removed:
31 *
32 * Last changed in libpng 1.6.19 [November 12, 2015]
33 * Copyright (c) 1998-2015 Glenn Randers-Pehrson
34 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
35 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
36 *
37 * This code is released under the libpng license.
38 * For conditions of distribution and use, see the disclaimer
39 * and license in png.h
40 *
41 * This file contains functions optionally called by an application
42 * in order to tell libpng how to handle data when reading a PNG.
43 * Transformations that are used in both reading and writing are
44 * in pngtrans.c.
45 */
46
47 #include "pngpriv.h"
48
49 #ifdef PNG_READ_SUPPORTED
50
51 /* Set the action on getting a CRC error for an ancillary or critical chunk. */
52 void PNGAPI
53 png_set_crc_action(png_structrp png_ptr, int crit_action, int ancil_action)
300
301 #ifdef PNG_READ_ALPHA_MODE_SUPPORTED
302 void PNGFAPI
303 png_set_alpha_mode_fixed(png_structrp png_ptr, int mode,
304 png_fixed_point output_gamma)
305 {
306 int compose = 0;
307 png_fixed_point file_gamma;
308
309 png_debug(1, "in png_set_alpha_mode");
310
311 if (png_rtran_ok(png_ptr, 0) == 0)
312 return;
313
314 output_gamma = translate_gamma_flags(png_ptr, output_gamma, 1/*screen*/);
315
316 /* Validate the value to ensure it is in a reasonable range. The value
317 * is expected to be 1 or greater, but this range test allows for some
318 * viewing correction values. The intent is to weed out users of this API
319 * who use the inverse of the gamma value accidentally! Since some of these
320 * values are reasonable this may have to be changed.
321 */
322 if (output_gamma < 70000 || output_gamma > 300000)
323 png_error(png_ptr, "output gamma out of expected range");
324
325 /* The default file gamma is the inverse of the output gamma; the output
326 * gamma may be changed below so get the file value first:
327 */
328 file_gamma = png_reciprocal(output_gamma);
329
330 /* There are really 8 possibilities here, composed of any combination
331 * of:
332 *
333 * premultiply the color channels
334 * do not encode non-opaque pixels
335 * encode the alpha as well as the color channels
336 *
337 * The differences disappear if the input/output ('screen') gamma is 1.0,
338 * because then the encoding is a no-op and there is only the choice of
339 * premultiplying the color channels or not.
340 *
341 * png_set_alpha_mode and png_set_background interact because both use
342 * png_compose to do the work. Calling both is only useful when
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12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13 * version 2 for more details (a copy is included in the LICENSE file that
14 * accompanied this code).
15 *
16 * You should have received a copy of the GNU General Public License version
17 * 2 along with this work; if not, write to the Free Software Foundation,
18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19 *
20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21 * or visit www.oracle.com if you need additional information or have any
22 * questions.
23 */
24
25 /* pngrtran.c - transforms the data in a row for PNG readers
26 *
27 * This file is available under and governed by the GNU General Public
28 * License version 2 only, as published by the Free Software Foundation.
29 * However, the following notice accompanied the original version of this
30 * file and, per its terms, should not be removed:
31 *
32 * Last changed in libpng 1.6.22 [May 26, 2016]
33 * Copyright (c) 1998-2002,2004,2006-2016 Glenn Randers-Pehrson
34 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
35 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
36 *
37 * This code is released under the libpng license.
38 * For conditions of distribution and use, see the disclaimer
39 * and license in png.h
40 *
41 * This file contains functions optionally called by an application
42 * in order to tell libpng how to handle data when reading a PNG.
43 * Transformations that are used in both reading and writing are
44 * in pngtrans.c.
45 */
46
47 #include "pngpriv.h"
48
49 #ifdef PNG_READ_SUPPORTED
50
51 /* Set the action on getting a CRC error for an ancillary or critical chunk. */
52 void PNGAPI
53 png_set_crc_action(png_structrp png_ptr, int crit_action, int ancil_action)
300
301 #ifdef PNG_READ_ALPHA_MODE_SUPPORTED
302 void PNGFAPI
303 png_set_alpha_mode_fixed(png_structrp png_ptr, int mode,
304 png_fixed_point output_gamma)
305 {
306 int compose = 0;
307 png_fixed_point file_gamma;
308
309 png_debug(1, "in png_set_alpha_mode");
310
311 if (png_rtran_ok(png_ptr, 0) == 0)
312 return;
313
314 output_gamma = translate_gamma_flags(png_ptr, output_gamma, 1/*screen*/);
315
316 /* Validate the value to ensure it is in a reasonable range. The value
317 * is expected to be 1 or greater, but this range test allows for some
318 * viewing correction values. The intent is to weed out users of this API
319 * who use the inverse of the gamma value accidentally! Since some of these
320 * values are reasonable this may have to be changed:
321 *
322 * 1.6.x: changed from 0.07..3 to 0.01..100 (to accomodate the optimal 16-bit
323 * gamma of 36, and its reciprocal.)
324 */
325 if (output_gamma < 1000 || output_gamma > 10000000)
326 png_error(png_ptr, "output gamma out of expected range");
327
328 /* The default file gamma is the inverse of the output gamma; the output
329 * gamma may be changed below so get the file value first:
330 */
331 file_gamma = png_reciprocal(output_gamma);
332
333 /* There are really 8 possibilities here, composed of any combination
334 * of:
335 *
336 * premultiply the color channels
337 * do not encode non-opaque pixels
338 * encode the alpha as well as the color channels
339 *
340 * The differences disappear if the input/output ('screen') gamma is 1.0,
341 * because then the encoding is a no-op and there is only the choice of
342 * premultiplying the color channels or not.
343 *
344 * png_set_alpha_mode and png_set_background interact because both use
345 * png_compose to do the work. Calling both is only useful when
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