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view libs/imago/file_png.c @ 15:2d48f65da357
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| author | John Tsiombikas <nuclear@member.fsf.org> |
|---|---|
| date | Sun, 07 Jun 2015 20:40:37 +0300 |
| parents | |
| children |
line source
1 /*
2 libimago - a multi-format image file input/output library.
3 Copyright (C) 2010 John Tsiombikas <nuclear@member.fsf.org>
5 This program is free software: you can redistribute it and/or modify
6 it under the terms of the GNU Lesser General Public License as published
7 by the Free Software Foundation, either version 3 of the License, or
8 (at your option) any later version.
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU Lesser General Public License for more details.
15 You should have received a copy of the GNU Lesser General Public License
16 along with this program. If not, see <http://www.gnu.org/licenses/>.
17 */
19 /* -- PNG module -- */
21 #include <stdlib.h>
22 #include <png.h>
23 #include "imago2.h"
24 #include "ftype_module.h"
26 static int check_file(struct img_io *io);
27 static int read_file(struct img_pixmap *img, struct img_io *io);
28 static int write_file(struct img_pixmap *img, struct img_io *io);
30 static void read_func(png_struct *png, unsigned char *data, size_t len);
31 static void write_func(png_struct *png, unsigned char *data, size_t len);
32 static void flush_func(png_struct *png);
34 static int png_type_to_fmt(int color_type, int channel_bits);
35 static int fmt_to_png_type(enum img_fmt fmt);
38 int img_register_png(void)
39 {
40 static struct ftype_module mod = {".png", check_file, read_file, write_file};
41 return img_register_module(&mod);
42 }
44 static int check_file(struct img_io *io)
45 {
46 unsigned char sig[8];
47 int res;
48 long pos = io->seek(0, SEEK_CUR, io->uptr);
50 if(io->read(sig, 8, io->uptr) < 8) {
51 io->seek(pos, SEEK_SET, io->uptr);
52 return -1;
53 }
55 res = png_sig_cmp(sig, 0, 8) == 0 ? 0 : -1;
56 io->seek(pos, SEEK_SET, io->uptr);
57 return res;
58 }
60 static int read_file(struct img_pixmap *img, struct img_io *io)
61 {
62 png_struct *png;
63 png_info *info;
64 int channel_bits, color_type, ilace_type, compression, filtering, fmt;
65 png_uint_32 xsz, ysz;
67 if(!(png = png_create_read_struct(PNG_LIBPNG_VER_STRING, 0, 0, 0))) {
68 return -1;
69 }
71 if(!(info = png_create_info_struct(png))) {
72 png_destroy_read_struct(&png, 0, 0);
73 return -1;
74 }
76 if(setjmp(png_jmpbuf(png))) {
77 png_destroy_read_struct(&png, &info, 0);
78 return -1;
79 }
81 png_set_read_fn(png, io, read_func);
82 png_set_sig_bytes(png, 0);
83 png_read_png(png, info, 0, 0);
85 png_get_IHDR(png, info, &xsz, &ysz, &channel_bits, &color_type, &ilace_type,
86 &compression, &filtering);
87 if((fmt = png_type_to_fmt(color_type, channel_bits)) == -1) {
88 png_destroy_read_struct(&png, &info, 0);
89 return -1;
90 }
92 if(img_set_pixels(img, xsz, ysz, fmt, 0) == -1) {
93 png_destroy_read_struct(&png, &info, 0);
94 return -1;
95 }
98 if(channel_bits == 8) {
99 unsigned int i;
100 unsigned char **lineptr = (unsigned char**)png_get_rows(png, info);
101 unsigned char *dest = img->pixels;
103 for(i=0; i<ysz; i++) {
104 memcpy(dest, lineptr[i], xsz * img->pixelsz);
105 dest += xsz * img->pixelsz;
106 }
107 } else {
108 unsigned int i, j, num_elem;
109 unsigned char **lineptr = (unsigned char**)png_get_rows(png, info);
110 float *dest = img->pixels;
112 num_elem = img->pixelsz / sizeof(float);
113 for(i=0; i<ysz; i++) {
114 for(j=0; j<xsz * num_elem; j++) {
115 unsigned short val = (lineptr[i][j * 2] << 8) | lineptr[i][j * 2 + 1];
116 *dest++ = (float)val / 65535.0;
117 }
118 }
119 }
122 png_destroy_read_struct(&png, &info, 0);
123 return 0;
124 }
127 static int write_file(struct img_pixmap *img, struct img_io *io)
128 {
129 png_struct *png;
130 png_info *info;
131 png_text txt;
132 struct img_pixmap tmpimg;
133 unsigned char **rows;
134 unsigned char *pixptr;
135 int i, coltype;
137 img_init(&tmpimg);
139 if(!(png = png_create_write_struct(PNG_LIBPNG_VER_STRING, 0, 0, 0))) {
140 return -1;
141 }
142 if(!(info = png_create_info_struct(png))) {
143 png_destroy_write_struct(&png, 0);
144 return -1;
145 }
147 /* if the input image is floating-point, we need to convert it to integer */
148 if(img_is_float(img)) {
149 if(img_copy(&tmpimg, img) == -1) {
150 return -1;
151 }
152 if(img_to_integer(&tmpimg) == -1) {
153 img_destroy(&tmpimg);
154 return -1;
155 }
156 img = &tmpimg;
157 }
159 txt.compression = PNG_TEXT_COMPRESSION_NONE;
160 txt.key = "Software";
161 txt.text = "libimago2";
162 txt.text_length = 0;
164 if(setjmp(png_jmpbuf(png))) {
165 png_destroy_write_struct(&png, &info);
166 img_destroy(&tmpimg);
167 return -1;
168 }
169 png_set_write_fn(png, io, write_func, flush_func);
171 coltype = fmt_to_png_type(img->fmt);
172 png_set_IHDR(png, info, img->width, img->height, 8, coltype, PNG_INTERLACE_NONE,
173 PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
174 png_set_text(png, info, &txt, 1);
176 if(!(rows = malloc(img->height * sizeof *rows))) {
177 png_destroy_write_struct(&png, &info);
178 img_destroy(&tmpimg);
179 return -1;
180 }
182 pixptr = img->pixels;
183 for(i=0; i<img->height; i++) {
184 rows[i] = pixptr;
185 pixptr += img->width * img->pixelsz;
186 }
187 png_set_rows(png, info, rows);
189 png_write_png(png, info, 0, 0);
190 png_write_end(png, info);
191 png_destroy_write_struct(&png, &info);
193 free(rows);
195 img_destroy(&tmpimg);
196 return 0;
197 }
199 static void read_func(png_struct *png, unsigned char *data, size_t len)
200 {
201 struct img_io *io = (struct img_io*)png_get_io_ptr(png);
203 if(io->read(data, len, io->uptr) == -1) {
204 longjmp(png_jmpbuf(png), 1);
205 }
206 }
208 static void write_func(png_struct *png, unsigned char *data, size_t len)
209 {
210 struct img_io *io = (struct img_io*)png_get_io_ptr(png);
212 if(io->write(data, len, io->uptr) == -1) {
213 longjmp(png_jmpbuf(png), 1);
214 }
215 }
217 static void flush_func(png_struct *png)
218 {
219 /* XXX does it matter that we can't flush? */
220 }
222 static int png_type_to_fmt(int color_type, int channel_bits)
223 {
224 /* only 8 and 16 bits per channel ar supported at the moment */
225 if(channel_bits != 8 && channel_bits != 16) {
226 return -1;
227 }
229 switch(color_type) {
230 case PNG_COLOR_TYPE_RGB:
231 return channel_bits == 16 ? IMG_FMT_RGBF : IMG_FMT_RGB24;
233 case PNG_COLOR_TYPE_RGB_ALPHA:
234 return channel_bits == 16 ? IMG_FMT_RGBAF : IMG_FMT_RGBA32;
236 case PNG_COLOR_TYPE_GRAY:
237 return channel_bits == 16 ? IMG_FMT_GREYF : IMG_FMT_GREY8;
239 default:
240 break;
241 }
242 return -1;
243 }
245 static int fmt_to_png_type(enum img_fmt fmt)
246 {
247 switch(fmt) {
248 case IMG_FMT_GREY8:
249 return PNG_COLOR_TYPE_GRAY;
251 case IMG_FMT_RGB24:
252 return PNG_COLOR_TYPE_RGB;
254 case IMG_FMT_RGBA32:
255 return PNG_COLOR_TYPE_RGBA;
257 default:
258 break;
259 }
260 return -1;
261 }