png2pnm.c@ 103585

最後變更在這個檔案從103585是 103316,由 vboxsync 提交於 12 月前
libpng-1.6.42: Applied and adjusted our libpng changes to 1.6.42. bugref:8515
屬性 svn:eol-style 設為 `native`
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1	/*
2	* png2pnm.c --- conversion from PNG-file to PGM/PPM-file
3	* copyright (C) 1999-2019 by Willem van Schaik <willem at schaik dot com>
4	*
5	* This software is released under the MIT license. For conditions of
6	* distribution and use, see the LICENSE file part of this package.
7	*/
8
9	#include <stdio.h>
10	#include <stdlib.h>
11	#include <fcntl.h>
12
13	#ifndef BOOL
14	#define BOOL unsigned char
15	#endif
16	#ifndef TRUE
17	#define TRUE ((BOOL) 1)
18	#endif
19	#ifndef FALSE
20	#define FALSE ((BOOL) 0)
21	#endif
22
23	#include "png.h"
24
25	/* function prototypes */
26
27	int main (int argc, char *argv[]);
28	void usage ();
29	BOOL png2pnm (FILE png_file, FILE pnm_file, FILE *alpha_file,
30	BOOL raw, BOOL alpha);
31	BOOL do_png2pnm (png_struct png_ptr, png_info info_ptr,
32	FILE pnm_file, FILE alpha_file,
33	BOOL raw, BOOL alpha);
34
35	/*
36	* main
37	*/
38
39	int main (int argc, char *argv[])
40	{
41	FILE *fp_rd = stdin;
42	FILE *fp_wr = stdout;
43	FILE *fp_al = NULL;
44	const char *fname_wr = NULL;
45	const char *fname_al = NULL;
46	BOOL raw = TRUE;
47	BOOL alpha = FALSE;
48	int argi;
49	int ret;
50
51	for (argi = 1; argi < argc; argi++)
52	{
53	if (argv[argi][0] == '-')
54	{
55	switch (argv[argi][1])
56	{
57	case 'n':
58	raw = FALSE;
59	break;
60	case 'r':
61	raw = TRUE;
62	break;
63	case 'a':
64	alpha = TRUE;
65	argi++;
66	if ((fp_al = fopen (argv[argi], "wb")) == NULL)
67	{
68	fname_al = argv[argi];
69	fprintf (stderr, "PNM2PNG\n");
70	fprintf (stderr, "Error: cannot create alpha-channel file %s\n",
71	argv[argi]);
72	exit (1);
73	}
74	break;
75	case 'h':
76	case '?':
77	usage ();
78	exit (0);
79	break;
80	default:
81	fprintf (stderr, "PNG2PNM\n");
82	fprintf (stderr, "Error: unknown option %s\n", argv[argi]);
83	usage ();
84	exit (1);
85	break;
86	} /* end switch */
87	}
88	else if (fp_rd == stdin)
89	{
90	if ((fp_rd = fopen (argv[argi], "rb")) == NULL)
91	{
92	fprintf (stderr, "PNG2PNM\n");
93	fprintf (stderr, "Error: file %s does not exist\n", argv[argi]);
94	exit (1);
95	}
96	}
97	else if (fp_wr == stdout)
98	{
99	fname_wr = argv[argi];
100	if ((fp_wr = fopen (argv[argi], "wb")) == NULL)
101	{
102	fprintf (stderr, "PNG2PNM\n");
103	fprintf (stderr, "Error: cannot create file %s\n", argv[argi]);
104	exit (1);
105	}
106	}
107	else
108	{
109	fprintf (stderr, "PNG2PNM\n");
110	fprintf (stderr, "Error: too many parameters\n");
111	usage ();
112	exit (1);
113	}
114	} /* end for */
115
116	#if defined(O_BINARY) && (O_BINARY != 0)
117	/* set stdin/stdout if required to binary */
118	if (fp_rd == stdin)
119	setmode (fileno (stdin), O_BINARY);
120	if ((raw) && (fp_wr == stdout))
121	setmode (fileno (stdout), O_BINARY);
122	#endif
123
124	/* call the conversion program itself */
125	ret = png2pnm (fp_rd, fp_wr, fp_al, raw, alpha);
126
127	/* close input file */
128	fclose (fp_rd);
129	/* close output file */
130	fclose (fp_wr);
131	/* close alpha file */
132	if (alpha)
133	fclose (fp_al);
134
135	if (!ret)
136	{
137	fprintf (stderr, "PNG2PNM\n");
138	fprintf (stderr, "Error: unsuccessful conversion of PNG-image\n");
139	if (fname_wr)
140	remove (fname_wr); /* no broken output file shall remain behind */
141	if (fname_al)
142	remove (fname_al); /* ditto */
143	exit (1);
144	}
145
146	return 0;
147	}
148
149	/*
150	* usage
151	*/
152
153	void usage ()
154	{
155	fprintf (stderr, "PNG2PNM\n");
156	fprintf (stderr, " by Willem van Schaik, 1999\n");
157	fprintf (stderr, "Usage: png2pnm [options] <file>.png [<file>.pnm]\n");
158	fprintf (stderr, " or: ... \| png2pnm [options]\n");
159	fprintf (stderr, "Options:\n");
160	fprintf (stderr,
161	" -r[aw] write pnm-file in binary format (P4/P5/P6) (default)\n");
162	fprintf (stderr, " -n[oraw] write pnm-file in ascii format (P1/P2/P3)\n");
163	fprintf (stderr,
164	" -a[lpha] <file>.pgm write PNG alpha channel as pgm-file\n");
165	fprintf (stderr, " -h \| -? print this help-information\n");
166	}
167
168	/*
169	* png2pnm
170	*/
171
172	BOOL png2pnm (FILE png_file, FILE pnm_file, FILE *alpha_file,
173	BOOL raw, BOOL alpha)
174	{
175	png_struct *png_ptr;
176	png_info *info_ptr;
177	BOOL ret;
178
179	/* initialize the libpng context for reading from png_file */
180
181	png_ptr = png_create_read_struct (png_get_libpng_ver(NULL),
182	NULL, NULL, NULL);
183	if (!png_ptr)
184	return FALSE; /* out of memory */
185
186	info_ptr = png_create_info_struct (png_ptr);
187	if (!info_ptr)
188	{
189	png_destroy_read_struct (&png_ptr, NULL, NULL);
190	return FALSE; /* out of memory */
191	}
192
193	if (setjmp (png_jmpbuf (png_ptr)))
194	{
195	png_destroy_read_struct (&png_ptr, &info_ptr, NULL);
196	return FALSE; /* generic libpng error */
197	}
198
199	png_init_io (png_ptr, png_file);
200
201	/* do the actual conversion */
202	ret = do_png2pnm (png_ptr, info_ptr, pnm_file, alpha_file, raw, alpha);
203
204	/* clean up the libpng structures and their internally-managed data */
205	png_destroy_read_struct (&png_ptr, &info_ptr, NULL);
206
207	return ret;
208	}
209
210	/*
211	* do_png2pnm - does the conversion in a fully-initialized libpng context
212	*/
213
214	BOOL do_png2pnm (png_struct png_ptr, png_info info_ptr,
215	FILE pnm_file, FILE alpha_file,
216	BOOL raw, BOOL alpha)
217	{
218	png_byte **row_pointers;
219	png_byte *pix_ptr;
220	png_uint_32 width;
221	png_uint_32 height;
222	int bit_depth;
223	int channels;
224	int color_type;
225	int alpha_present;
226	png_uint_32 row, col, i;
227	long dep_16;
228
229	/* set up the image transformations that are necessary for the PNM format */
230
231	/* set up (if applicable) the expansion of paletted images to full-color rgb,
232	* and the expansion of transparency maps to full alpha-channel */
233	png_set_expand (png_ptr);
234
235	/* set up (if applicable) the expansion of grayscale images to bit-depth 8 */
236	png_set_expand_gray_1_2_4_to_8 (png_ptr);
237
238	#ifdef NJET
239	/* downgrade 16-bit images to 8-bit */
240	if (bit_depth == 16)
241	png_set_strip_16 (png_ptr);
242	/* transform grayscale images into full-color */
243	if (color_type == PNG_COLOR_TYPE_GRAY \|\|
244	color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
245	png_set_gray_to_rgb (png_ptr);
246	/* if the PNG image has a gAMA chunk then gamma-correct the output image */
247	{
248	double file_gamma;
249	if (png_get_gAMA (png_ptr, info_ptr, &file_gamma))
250	png_set_gamma (png_ptr, (double) 2.2, file_gamma);
251	}
252	#endif
253
254	/* read the image file, with all of the above image transforms applied */
255	png_read_png (png_ptr, info_ptr, 0, NULL);
256
257	/* get the image size, bit-depth and color-type */
258	png_get_IHDR (png_ptr, info_ptr, &width, &height, &bit_depth, &color_type,
259	NULL, NULL, NULL);
260
261	/* calculate the number of channels and store alpha-presence */
262	if (color_type == PNG_COLOR_TYPE_GRAY)
263	channels = 1;
264	else if (color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
265	channels = 2;
266	else if (color_type == PNG_COLOR_TYPE_RGB)
267	channels = 3;
268	else if (color_type == PNG_COLOR_TYPE_RGB_ALPHA)
269	channels = 4;
270	else
271	channels = 0; /* should never happen */
272	alpha_present = (channels - 1) % 2;
273
274	/* check if alpha is expected to be present in file */
275	if (alpha && !alpha_present)
276	{
277	fprintf (stderr, "PNG2PNM\n");
278	fprintf (stderr, "Warning: no alpha channel in PNG file\n");
279	return FALSE;
280	}
281
282	/* get address of internally-allocated image data */
283	row_pointers = png_get_rows (png_ptr, info_ptr);
284
285	/* write header of PNM file */
286
287	if ((color_type == PNG_COLOR_TYPE_GRAY) \|\|
288	(color_type == PNG_COLOR_TYPE_GRAY_ALPHA))
289	{
290	fprintf (pnm_file, "%s\n", (raw) ? "P5" : "P2");
291	fprintf (pnm_file, "%d %d\n", (int) width, (int) height);
292	fprintf (pnm_file, "%ld\n", ((1L << (int) bit_depth) - 1L));
293	}
294	else if ((color_type == PNG_COLOR_TYPE_RGB) \|\|
295	(color_type == PNG_COLOR_TYPE_RGB_ALPHA))
296	{
297	fprintf (pnm_file, "%s\n", (raw) ? "P6" : "P3");
298	fprintf (pnm_file, "%d %d\n", (int) width, (int) height);
299	fprintf (pnm_file, "%ld\n", ((1L << (int) bit_depth) - 1L));
300	}
301
302	/* write header of PGM file with alpha channel */
303
304	if ((alpha) &&
305	((color_type == PNG_COLOR_TYPE_GRAY_ALPHA) \|\|
306	(color_type == PNG_COLOR_TYPE_RGB_ALPHA)))
307	{
308	fprintf (alpha_file, "%s\n", (raw) ? "P5" : "P2");
309	fprintf (alpha_file, "%d %d\n", (int) width, (int) height);
310	fprintf (alpha_file, "%ld\n", ((1L << (int) bit_depth) - 1L));
311	}
312
313	/* write data to PNM file */
314
315	for (row = 0; row < height; row++)
316	{
317	pix_ptr = row_pointers[row];
318	for (col = 0; col < width; col++)
319	{
320	for (i = 0; i < (png_uint_32) (channels - alpha_present); i++)
321	{
322	if (raw)
323	{
324	fputc ((int) *pix_ptr++, pnm_file);
325	if (bit_depth == 16)
326	fputc ((int) *pix_ptr++, pnm_file);
327	}
328	else
329	{
330	if (bit_depth == 16)
331	{
332	dep_16 = ((long) *pix_ptr++) << 8;
333	dep_16 += ((long) *pix_ptr++);
334	fprintf (pnm_file, "%ld ", dep_16);
335	}
336	else
337	{
338	fprintf (pnm_file, "%ld ", (long) *pix_ptr++);
339	}
340	}
341	}
342	if (alpha_present)
343	{
344	if (!alpha)
345	{
346	/* skip the alpha-channel */
347	pix_ptr++;
348	if (bit_depth == 16)
349	pix_ptr++;
350	}
351	else
352	{
353	/* output the alpha-channel as pgm file */
354	if (raw)
355	{
356	fputc ((int) *pix_ptr++, alpha_file);
357	if (bit_depth == 16)
358	fputc ((int) *pix_ptr++, alpha_file);
359	}
360	else
361	{
362	if (bit_depth == 16)
363	{
364	dep_16 = ((long) *pix_ptr++) << 8;
365	dep_16 += ((long) *pix_ptr++);
366	fprintf (alpha_file, "%ld ", dep_16);
367	}
368	else
369	{
370	fprintf (alpha_file, "%ld ", (long) *pix_ptr++);
371	}
372	}
373	}
374	} /* end if alpha_present */
375
376	if (!raw)
377	if (col % 4 == 3)
378	fprintf (pnm_file, "\n");
379	} /* end for col */
380
381	if (!raw)
382	if (col % 4 != 0)
383	fprintf (pnm_file, "\n");
384	} /* end for row */
385
386	return TRUE;
387	} /* end of source */

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