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annotate 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
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nuclear@14 1 /*
nuclear@14 2 libimago - a multi-format image file input/output library.
nuclear@14 3 Copyright (C) 2010 John Tsiombikas <nuclear@member.fsf.org>
nuclear@14 4
nuclear@14 5 This program is free software: you can redistribute it and/or modify
nuclear@14 6 it under the terms of the GNU Lesser General Public License as published
nuclear@14 7 by the Free Software Foundation, either version 3 of the License, or
nuclear@14 8 (at your option) any later version.
nuclear@14 9
nuclear@14 10 This program is distributed in the hope that it will be useful,
nuclear@14 11 but WITHOUT ANY WARRANTY; without even the implied warranty of
nuclear@14 12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
nuclear@14 13 GNU Lesser General Public License for more details.
nuclear@14 14
nuclear@14 15 You should have received a copy of the GNU Lesser General Public License
nuclear@14 16 along with this program. If not, see <http://www.gnu.org/licenses/>.
nuclear@14 17 */
nuclear@14 18
nuclear@14 19 /* -- PNG module -- */
nuclear@14 20
nuclear@14 21 #include <stdlib.h>
nuclear@14 22 #include <png.h>
nuclear@14 23 #include "imago2.h"
nuclear@14 24 #include "ftype_module.h"
nuclear@14 25
nuclear@14 26 static int check_file(struct img_io *io);
nuclear@14 27 static int read_file(struct img_pixmap *img, struct img_io *io);
nuclear@14 28 static int write_file(struct img_pixmap *img, struct img_io *io);
nuclear@14 29
nuclear@14 30 static void read_func(png_struct *png, unsigned char *data, size_t len);
nuclear@14 31 static void write_func(png_struct *png, unsigned char *data, size_t len);
nuclear@14 32 static void flush_func(png_struct *png);
nuclear@14 33
nuclear@14 34 static int png_type_to_fmt(int color_type, int channel_bits);
nuclear@14 35 static int fmt_to_png_type(enum img_fmt fmt);
nuclear@14 36
nuclear@14 37
nuclear@14 38 int img_register_png(void)
nuclear@14 39 {
nuclear@14 40 static struct ftype_module mod = {".png", check_file, read_file, write_file};
nuclear@14 41 return img_register_module(&mod);
nuclear@14 42 }
nuclear@14 43
nuclear@14 44 static int check_file(struct img_io *io)
nuclear@14 45 {
nuclear@14 46 unsigned char sig[8];
nuclear@14 47 int res;
nuclear@14 48 long pos = io->seek(0, SEEK_CUR, io->uptr);
nuclear@14 49
nuclear@14 50 if(io->read(sig, 8, io->uptr) < 8) {
nuclear@14 51 io->seek(pos, SEEK_SET, io->uptr);
nuclear@14 52 return -1;
nuclear@14 53 }
nuclear@14 54
nuclear@14 55 res = png_sig_cmp(sig, 0, 8) == 0 ? 0 : -1;
nuclear@14 56 io->seek(pos, SEEK_SET, io->uptr);
nuclear@14 57 return res;
nuclear@14 58 }
nuclear@14 59
nuclear@14 60 static int read_file(struct img_pixmap *img, struct img_io *io)
nuclear@14 61 {
nuclear@14 62 png_struct *png;
nuclear@14 63 png_info *info;
nuclear@14 64 int channel_bits, color_type, ilace_type, compression, filtering, fmt;
nuclear@14 65 png_uint_32 xsz, ysz;
nuclear@14 66
nuclear@14 67 if(!(png = png_create_read_struct(PNG_LIBPNG_VER_STRING, 0, 0, 0))) {
nuclear@14 68 return -1;
nuclear@14 69 }
nuclear@14 70
nuclear@14 71 if(!(info = png_create_info_struct(png))) {
nuclear@14 72 png_destroy_read_struct(&png, 0, 0);
nuclear@14 73 return -1;
nuclear@14 74 }
nuclear@14 75
nuclear@14 76 if(setjmp(png_jmpbuf(png))) {
nuclear@14 77 png_destroy_read_struct(&png, &info, 0);
nuclear@14 78 return -1;
nuclear@14 79 }
nuclear@14 80
nuclear@14 81 png_set_read_fn(png, io, read_func);
nuclear@14 82 png_set_sig_bytes(png, 0);
nuclear@14 83 png_read_png(png, info, 0, 0);
nuclear@14 84
nuclear@14 85 png_get_IHDR(png, info, &xsz, &ysz, &channel_bits, &color_type, &ilace_type,
nuclear@14 86 &compression, &filtering);
nuclear@14 87 if((fmt = png_type_to_fmt(color_type, channel_bits)) == -1) {
nuclear@14 88 png_destroy_read_struct(&png, &info, 0);
nuclear@14 89 return -1;
nuclear@14 90 }
nuclear@14 91
nuclear@14 92 if(img_set_pixels(img, xsz, ysz, fmt, 0) == -1) {
nuclear@14 93 png_destroy_read_struct(&png, &info, 0);
nuclear@14 94 return -1;
nuclear@14 95 }
nuclear@14 96
nuclear@14 97
nuclear@14 98 if(channel_bits == 8) {
nuclear@14 99 unsigned int i;
nuclear@14 100 unsigned char **lineptr = (unsigned char**)png_get_rows(png, info);
nuclear@14 101 unsigned char *dest = img->pixels;
nuclear@14 102
nuclear@14 103 for(i=0; i<ysz; i++) {
nuclear@14 104 memcpy(dest, lineptr[i], xsz * img->pixelsz);
nuclear@14 105 dest += xsz * img->pixelsz;
nuclear@14 106 }
nuclear@14 107 } else {
nuclear@14 108 unsigned int i, j, num_elem;
nuclear@14 109 unsigned char **lineptr = (unsigned char**)png_get_rows(png, info);
nuclear@14 110 float *dest = img->pixels;
nuclear@14 111
nuclear@14 112 num_elem = img->pixelsz / sizeof(float);
nuclear@14 113 for(i=0; i<ysz; i++) {
nuclear@14 114 for(j=0; j<xsz * num_elem; j++) {
nuclear@14 115 unsigned short val = (lineptr[i][j * 2] << 8) | lineptr[i][j * 2 + 1];
nuclear@14 116 *dest++ = (float)val / 65535.0;
nuclear@14 117 }
nuclear@14 118 }
nuclear@14 119 }
nuclear@14 120
nuclear@14 121
nuclear@14 122 png_destroy_read_struct(&png, &info, 0);
nuclear@14 123 return 0;
nuclear@14 124 }
nuclear@14 125
nuclear@14 126
nuclear@14 127 static int write_file(struct img_pixmap *img, struct img_io *io)
nuclear@14 128 {
nuclear@14 129 png_struct *png;
nuclear@14 130 png_info *info;
nuclear@14 131 png_text txt;
nuclear@14 132 struct img_pixmap tmpimg;
nuclear@14 133 unsigned char **rows;
nuclear@14 134 unsigned char *pixptr;
nuclear@14 135 int i, coltype;
nuclear@14 136
nuclear@14 137 img_init(&tmpimg);
nuclear@14 138
nuclear@14 139 if(!(png = png_create_write_struct(PNG_LIBPNG_VER_STRING, 0, 0, 0))) {
nuclear@14 140 return -1;
nuclear@14 141 }
nuclear@14 142 if(!(info = png_create_info_struct(png))) {
nuclear@14 143 png_destroy_write_struct(&png, 0);
nuclear@14 144 return -1;
nuclear@14 145 }
nuclear@14 146
nuclear@14 147 /* if the input image is floating-point, we need to convert it to integer */
nuclear@14 148 if(img_is_float(img)) {
nuclear@14 149 if(img_copy(&tmpimg, img) == -1) {
nuclear@14 150 return -1;
nuclear@14 151 }
nuclear@14 152 if(img_to_integer(&tmpimg) == -1) {
nuclear@14 153 img_destroy(&tmpimg);
nuclear@14 154 return -1;
nuclear@14 155 }
nuclear@14 156 img = &tmpimg;
nuclear@14 157 }
nuclear@14 158
nuclear@14 159 txt.compression = PNG_TEXT_COMPRESSION_NONE;
nuclear@14 160 txt.key = "Software";
nuclear@14 161 txt.text = "libimago2";
nuclear@14 162 txt.text_length = 0;
nuclear@14 163
nuclear@14 164 if(setjmp(png_jmpbuf(png))) {
nuclear@14 165 png_destroy_write_struct(&png, &info);
nuclear@14 166 img_destroy(&tmpimg);
nuclear@14 167 return -1;
nuclear@14 168 }
nuclear@14 169 png_set_write_fn(png, io, write_func, flush_func);
nuclear@14 170
nuclear@14 171 coltype = fmt_to_png_type(img->fmt);
nuclear@14 172 png_set_IHDR(png, info, img->width, img->height, 8, coltype, PNG_INTERLACE_NONE,
nuclear@14 173 PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
nuclear@14 174 png_set_text(png, info, &txt, 1);
nuclear@14 175
nuclear@14 176 if(!(rows = malloc(img->height * sizeof *rows))) {
nuclear@14 177 png_destroy_write_struct(&png, &info);
nuclear@14 178 img_destroy(&tmpimg);
nuclear@14 179 return -1;
nuclear@14 180 }
nuclear@14 181
nuclear@14 182 pixptr = img->pixels;
nuclear@14 183 for(i=0; i<img->height; i++) {
nuclear@14 184 rows[i] = pixptr;
nuclear@14 185 pixptr += img->width * img->pixelsz;
nuclear@14 186 }
nuclear@14 187 png_set_rows(png, info, rows);
nuclear@14 188
nuclear@14 189 png_write_png(png, info, 0, 0);
nuclear@14 190 png_write_end(png, info);
nuclear@14 191 png_destroy_write_struct(&png, &info);
nuclear@14 192
nuclear@14 193 free(rows);
nuclear@14 194
nuclear@14 195 img_destroy(&tmpimg);
nuclear@14 196 return 0;
nuclear@14 197 }
nuclear@14 198
nuclear@14 199 static void read_func(png_struct *png, unsigned char *data, size_t len)
nuclear@14 200 {
nuclear@14 201 struct img_io *io = (struct img_io*)png_get_io_ptr(png);
nuclear@14 202
nuclear@14 203 if(io->read(data, len, io->uptr) == -1) {
nuclear@14 204 longjmp(png_jmpbuf(png), 1);
nuclear@14 205 }
nuclear@14 206 }
nuclear@14 207
nuclear@14 208 static void write_func(png_struct *png, unsigned char *data, size_t len)
nuclear@14 209 {
nuclear@14 210 struct img_io *io = (struct img_io*)png_get_io_ptr(png);
nuclear@14 211
nuclear@14 212 if(io->write(data, len, io->uptr) == -1) {
nuclear@14 213 longjmp(png_jmpbuf(png), 1);
nuclear@14 214 }
nuclear@14 215 }
nuclear@14 216
nuclear@14 217 static void flush_func(png_struct *png)
nuclear@14 218 {
nuclear@14 219 /* XXX does it matter that we can't flush? */
nuclear@14 220 }
nuclear@14 221
nuclear@14 222 static int png_type_to_fmt(int color_type, int channel_bits)
nuclear@14 223 {
nuclear@14 224 /* only 8 and 16 bits per channel ar supported at the moment */
nuclear@14 225 if(channel_bits != 8 && channel_bits != 16) {
nuclear@14 226 return -1;
nuclear@14 227 }
nuclear@14 228
nuclear@14 229 switch(color_type) {
nuclear@14 230 case PNG_COLOR_TYPE_RGB:
nuclear@14 231 return channel_bits == 16 ? IMG_FMT_RGBF : IMG_FMT_RGB24;
nuclear@14 232
nuclear@14 233 case PNG_COLOR_TYPE_RGB_ALPHA:
nuclear@14 234 return channel_bits == 16 ? IMG_FMT_RGBAF : IMG_FMT_RGBA32;
nuclear@14 235
nuclear@14 236 case PNG_COLOR_TYPE_GRAY:
nuclear@14 237 return channel_bits == 16 ? IMG_FMT_GREYF : IMG_FMT_GREY8;
nuclear@14 238
nuclear@14 239 default:
nuclear@14 240 break;
nuclear@14 241 }
nuclear@14 242 return -1;
nuclear@14 243 }
nuclear@14 244
nuclear@14 245 static int fmt_to_png_type(enum img_fmt fmt)
nuclear@14 246 {
nuclear@14 247 switch(fmt) {
nuclear@14 248 case IMG_FMT_GREY8:
nuclear@14 249 return PNG_COLOR_TYPE_GRAY;
nuclear@14 250
nuclear@14 251 case IMG_FMT_RGB24:
nuclear@14 252 return PNG_COLOR_TYPE_RGB;
nuclear@14 253
nuclear@14 254 case IMG_FMT_RGBA32:
nuclear@14 255 return PNG_COLOR_TYPE_RGBA;
nuclear@14 256
nuclear@14 257 default:
nuclear@14 258 break;
nuclear@14 259 }
nuclear@14 260 return -1;
nuclear@14 261 }