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annotate libs/imago2/file_png.c @ 13:ea928c313344

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author John Tsiombikas <nuclear@member.fsf.org>
date Mon, 28 Sep 2015 19:04:50 +0300
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nuclear@2 1 /*
nuclear@2 2 libimago - a multi-format image file input/output library.
nuclear@2 3 Copyright (C) 2010 John Tsiombikas <nuclear@member.fsf.org>
nuclear@2 4
nuclear@2 5 This program is free software: you can redistribute it and/or modify
nuclear@2 6 it under the terms of the GNU Lesser General Public License as published
nuclear@2 7 by the Free Software Foundation, either version 3 of the License, or
nuclear@2 8 (at your option) any later version.
nuclear@2 9
nuclear@2 10 This program is distributed in the hope that it will be useful,
nuclear@2 11 but WITHOUT ANY WARRANTY; without even the implied warranty of
nuclear@2 12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
nuclear@2 13 GNU Lesser General Public License for more details.
nuclear@2 14
nuclear@2 15 You should have received a copy of the GNU Lesser General Public License
nuclear@2 16 along with this program. If not, see <http://www.gnu.org/licenses/>.
nuclear@2 17 */
nuclear@2 18
nuclear@2 19 /* -- PNG module -- */
nuclear@2 20
nuclear@2 21 #include <stdlib.h>
nuclear@2 22 #include <png.h>
nuclear@2 23 #include "imago2.h"
nuclear@2 24 #include "ftype_module.h"
nuclear@2 25
nuclear@2 26 static int check_file(struct img_io *io);
nuclear@2 27 static int read_file(struct img_pixmap *img, struct img_io *io);
nuclear@2 28 static int write_file(struct img_pixmap *img, struct img_io *io);
nuclear@2 29
nuclear@2 30 static void read_func(png_struct *png, unsigned char *data, size_t len);
nuclear@2 31 static void write_func(png_struct *png, unsigned char *data, size_t len);
nuclear@2 32 static void flush_func(png_struct *png);
nuclear@2 33
nuclear@2 34 static int png_type_to_fmt(int color_type, int channel_bits);
nuclear@2 35 static int fmt_to_png_type(enum img_fmt fmt);
nuclear@2 36
nuclear@2 37
nuclear@2 38 int img_register_png(void)
nuclear@2 39 {
nuclear@2 40 static struct ftype_module mod = {".png", check_file, read_file, write_file};
nuclear@2 41 return img_register_module(&mod);
nuclear@2 42 }
nuclear@2 43
nuclear@2 44 static int check_file(struct img_io *io)
nuclear@2 45 {
nuclear@2 46 unsigned char sig[8];
nuclear@2 47 int res;
nuclear@2 48 long pos = io->seek(0, SEEK_CUR, io->uptr);
nuclear@2 49
nuclear@2 50 if(io->read(sig, 8, io->uptr) < 8) {
nuclear@2 51 io->seek(pos, SEEK_SET, io->uptr);
nuclear@2 52 return -1;
nuclear@2 53 }
nuclear@2 54
nuclear@2 55 res = png_sig_cmp(sig, 0, 8) == 0 ? 0 : -1;
nuclear@2 56 io->seek(pos, SEEK_SET, io->uptr);
nuclear@2 57 return res;
nuclear@2 58 }
nuclear@2 59
nuclear@2 60 static int read_file(struct img_pixmap *img, struct img_io *io)
nuclear@2 61 {
nuclear@2 62 png_struct *png;
nuclear@2 63 png_info *info;
nuclear@2 64 unsigned char **lineptr, *dest;
nuclear@2 65 int i, channel_bits, color_type, ilace_type, compression, filtering, fmt;
nuclear@2 66 unsigned long xsz, ysz;
nuclear@2 67
nuclear@2 68 if(!(png = png_create_read_struct(PNG_LIBPNG_VER_STRING, 0, 0, 0))) {
nuclear@2 69 return -1;
nuclear@2 70 }
nuclear@2 71
nuclear@2 72 if(!(info = png_create_info_struct(png))) {
nuclear@2 73 png_destroy_read_struct(&png, 0, 0);
nuclear@2 74 return -1;
nuclear@2 75 }
nuclear@2 76
nuclear@2 77 if(setjmp(png_jmpbuf(png))) {
nuclear@2 78 png_destroy_read_struct(&png, &info, 0);
nuclear@2 79 return -1;
nuclear@2 80 }
nuclear@2 81
nuclear@2 82 png_set_read_fn(png, io, read_func);
nuclear@2 83 png_set_sig_bytes(png, 0);
nuclear@2 84 png_read_png(png, info, 0, 0);
nuclear@2 85
nuclear@2 86 png_get_IHDR(png, info, &xsz, &ysz, &channel_bits, &color_type, &ilace_type,
nuclear@2 87 &compression, &filtering);
nuclear@2 88 if((fmt = png_type_to_fmt(color_type, channel_bits)) == -1) {
nuclear@2 89 png_destroy_read_struct(&png, &info, 0);
nuclear@2 90 return -1;
nuclear@2 91 }
nuclear@2 92
nuclear@2 93 if(img_set_pixels(img, xsz, ysz, fmt, 0) == -1) {
nuclear@2 94 png_destroy_read_struct(&png, &info, 0);
nuclear@2 95 return -1;
nuclear@2 96 }
nuclear@2 97
nuclear@2 98 lineptr = (unsigned char**)png_get_rows(png, info);
nuclear@2 99
nuclear@2 100 dest = img->pixels;
nuclear@2 101 for(i=0; i<ysz; i++) {
nuclear@2 102 memcpy(dest, lineptr[i], xsz * img->pixelsz);
nuclear@2 103 dest += xsz * img->pixelsz;
nuclear@2 104 }
nuclear@2 105 png_destroy_read_struct(&png, &info, 0);
nuclear@2 106 return 0;
nuclear@2 107 }
nuclear@2 108
nuclear@2 109
nuclear@2 110 static int write_file(struct img_pixmap *img, struct img_io *io)
nuclear@2 111 {
nuclear@2 112 png_struct *png;
nuclear@2 113 png_info *info;
nuclear@2 114 png_text txt;
nuclear@2 115 struct img_pixmap tmpimg;
nuclear@2 116 unsigned char **rows;
nuclear@2 117 unsigned char *pixptr;
nuclear@2 118 int i, coltype;
nuclear@2 119
nuclear@2 120 img_init(&tmpimg);
nuclear@2 121
nuclear@2 122 if(!(png = png_create_write_struct(PNG_LIBPNG_VER_STRING, 0, 0, 0))) {
nuclear@2 123 return -1;
nuclear@2 124 }
nuclear@2 125 if(!(info = png_create_info_struct(png))) {
nuclear@2 126 png_destroy_write_struct(&png, 0);
nuclear@2 127 return -1;
nuclear@2 128 }
nuclear@2 129
nuclear@2 130 /* if the input image is floating-point, we need to convert it to integer */
nuclear@2 131 if(img_is_float(img)) {
nuclear@2 132 if(img_copy(&tmpimg, img) == -1) {
nuclear@2 133 return -1;
nuclear@2 134 }
nuclear@2 135 if(img_to_integer(&tmpimg) == -1) {
nuclear@2 136 img_destroy(&tmpimg);
nuclear@2 137 return -1;
nuclear@2 138 }
nuclear@2 139 img = &tmpimg;
nuclear@2 140 }
nuclear@2 141
nuclear@2 142 txt.compression = PNG_TEXT_COMPRESSION_NONE;
nuclear@2 143 txt.key = "Software";
nuclear@2 144 txt.text = "libimago2";
nuclear@2 145 txt.text_length = 0;
nuclear@2 146
nuclear@2 147 if(setjmp(png_jmpbuf(png))) {
nuclear@2 148 png_destroy_write_struct(&png, &info);
nuclear@2 149 img_destroy(&tmpimg);
nuclear@2 150 return -1;
nuclear@2 151 }
nuclear@2 152 png_set_write_fn(png, io, write_func, flush_func);
nuclear@2 153
nuclear@2 154 coltype = fmt_to_png_type(img->fmt);
nuclear@2 155 png_set_IHDR(png, info, img->width, img->height, 8, coltype, PNG_INTERLACE_NONE,
nuclear@2 156 PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
nuclear@2 157 png_set_text(png, info, &txt, 1);
nuclear@2 158
nuclear@2 159 if(!(rows = malloc(img->height * sizeof *rows))) {
nuclear@2 160 png_destroy_write_struct(&png, &info);
nuclear@2 161 img_destroy(&tmpimg);
nuclear@2 162 return -1;
nuclear@2 163 }
nuclear@2 164
nuclear@2 165 pixptr = img->pixels;
nuclear@2 166 for(i=0; i<img->height; i++) {
nuclear@2 167 rows[i] = pixptr;
nuclear@2 168 pixptr += img->width * img->pixelsz;
nuclear@2 169 }
nuclear@2 170 png_set_rows(png, info, rows);
nuclear@2 171
nuclear@2 172 png_write_png(png, info, 0, 0);
nuclear@2 173 png_write_end(png, info);
nuclear@2 174 png_destroy_write_struct(&png, &info);
nuclear@2 175
nuclear@2 176 free(rows);
nuclear@2 177
nuclear@2 178 img_destroy(&tmpimg);
nuclear@2 179 return 0;
nuclear@2 180 }
nuclear@2 181
nuclear@2 182 static void read_func(png_struct *png, unsigned char *data, size_t len)
nuclear@2 183 {
nuclear@2 184 struct img_io *io = (struct img_io*)png_get_io_ptr(png);
nuclear@2 185
nuclear@2 186 if(io->read(data, len, io->uptr) == -1) {
nuclear@2 187 longjmp(png_jmpbuf(png), 1);
nuclear@2 188 }
nuclear@2 189 }
nuclear@2 190
nuclear@2 191 static void write_func(png_struct *png, unsigned char *data, size_t len)
nuclear@2 192 {
nuclear@2 193 struct img_io *io = (struct img_io*)png_get_io_ptr(png);
nuclear@2 194
nuclear@2 195 if(io->write(data, len, io->uptr) == -1) {
nuclear@2 196 longjmp(png_jmpbuf(png), 1);
nuclear@2 197 }
nuclear@2 198 }
nuclear@2 199
nuclear@2 200 static void flush_func(png_struct *png)
nuclear@2 201 {
nuclear@2 202 /* XXX does it matter that we can't flush? */
nuclear@2 203 }
nuclear@2 204
nuclear@2 205 static int png_type_to_fmt(int color_type, int channel_bits)
nuclear@2 206 {
nuclear@2 207 /* we don't support non-8bit-per-channel images yet */
nuclear@2 208 if(channel_bits > 8) {
nuclear@2 209 return -1;
nuclear@2 210 }
nuclear@2 211
nuclear@2 212 switch(color_type) {
nuclear@2 213 case PNG_COLOR_TYPE_RGB:
nuclear@2 214 return IMG_FMT_RGB24;
nuclear@2 215
nuclear@2 216 case PNG_COLOR_TYPE_RGB_ALPHA:
nuclear@2 217 return IMG_FMT_RGBA32;
nuclear@2 218
nuclear@2 219 case PNG_COLOR_TYPE_GRAY:
nuclear@2 220 return IMG_FMT_GREY8;
nuclear@2 221
nuclear@2 222 default:
nuclear@2 223 break;
nuclear@2 224 }
nuclear@2 225 return -1;
nuclear@2 226 }
nuclear@2 227
nuclear@2 228 static int fmt_to_png_type(enum img_fmt fmt)
nuclear@2 229 {
nuclear@2 230 switch(fmt) {
nuclear@2 231 case IMG_FMT_GREY8:
nuclear@2 232 return PNG_COLOR_TYPE_GRAY;
nuclear@2 233
nuclear@2 234 case IMG_FMT_RGB24:
nuclear@2 235 return PNG_COLOR_TYPE_RGB;
nuclear@2 236
nuclear@2 237 case IMG_FMT_RGBA32:
nuclear@2 238 return PNG_COLOR_TYPE_RGBA;
nuclear@2 239
nuclear@2 240 default:
nuclear@2 241 break;
nuclear@2 242 }
nuclear@2 243 return -1;
nuclear@2 244 }