src/graphics/image_png.c

   1 /************************************************************************
   2 * image_png.c
   3 * voxelands - 3d voxel world sandbox game
   4 * Copyright (C) Lisa 'darkrose' Milne 2016 <lisa@ltmnet.com>
   5 *
   6 * This program is free software: you can redistribute it and/or modify
   7 * it under the terms of the GNU General Public License as published by
   8 * the Free Software Foundation, either version 3 of the License, or
   9 * (at your option) any later version.
  10 *
  11 * This program is distributed in the hope that it will be useful, but
  12 * WITHOUT ANY WARRANTY; without even the implied warranty of
  13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  14 * See the GNU General Public License for more details.
  15 *
  16 * You should have received a copy of the GNU General Public License
  17 * along with this program.  If not, see <http://www.gnu.org/licenses/>
  18 ************************************************************************/
  19
  20 #include "common.h"
  21 #include "graphics.h"
  22 #include "file.h"
  23 #include "path.h"
  24
  25 #include <string.h>
  26 #include <png.h>
  27
  28 static void user_read_fn(png_structp png_ptr, png_bytep buffer, png_size_t size)
  29 {
  30         file_t *data = png_get_io_ptr(png_ptr);
  31         if( data->len && (data->pos + size) > data->len )
  32         {
  33                 png_error(png_ptr, "read error loading image");
  34                 return;
  35         }
  36
  37         memcpy(buffer, data->data + data->pos, size);
  38         data->pos += size;
  39 }
  40
  41 /* is it a png image? */
  42 int image_is_png(file_t *f)
  43 {
  44         return png_check_sig(f->data, 4);
  45 }
  46
  47 /* load a png image to pixel data */
  48 int image_load_png(file_t *f, image_t *p)
  49 {
  50         png_structp png_ptr;
  51         png_infop info_ptr;
  52         unsigned int sig_read = 0;
  53         png_uint_32 width, height;
  54         int bit_depth;
  55         int color_type;
  56         int interlace_type;
  57         int i;
  58         int rowbytes;
  59         int bpp;
  60         png_bytep *row_pointers;
  61
  62         png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
  63         if (png_ptr == NULL)
  64                 return 1;
  65
  66         png_set_error_fn(png_ptr, NULL, NULL, NULL);
  67         png_set_read_fn(png_ptr, (png_voidp)f, user_read_fn);
  68         info_ptr = png_create_info_struct(png_ptr);
  69         if (!info_ptr) {
  70                 png_destroy_read_struct(&png_ptr, NULL, NULL);
  71                 return 1;
  72         }
  73
  74         /* this is libpng's error handling, if something goes bad we'll
  75          * end up jumping back here where we can exit gracefullyish */
  76         if (setjmp(png_jmpbuf(png_ptr))) {
  77                 png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
  78                 return 1;
  79         }
  80
  81         png_init_io(png_ptr, (FILE*)f);
  82         png_set_sig_bytes(png_ptr, sig_read);
  83         png_read_info(png_ptr, info_ptr);
  84         png_get_IHDR(png_ptr, info_ptr, &width, &height, &bit_depth, &color_type, &interlace_type, NULL, NULL);
  85
  86         p->w = width;
  87         p->h = height;
  88
  89         if (color_type == PNG_COLOR_TYPE_PALETTE)
  90                 png_set_expand(png_ptr);
  91         if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8)
  92                 png_set_expand(png_ptr);
  93         if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS))
  94                 png_set_expand(png_ptr);
  95
  96         png_read_update_info(png_ptr, info_ptr);
  97
  98         /* get the size of image rows in bytes */
  99         rowbytes = png_get_rowbytes(png_ptr, info_ptr);
 100         bpp = rowbytes/width;
 101
 102         p->pixels = malloc(sizeof(png_byte)*(rowbytes * height));
 103         if (!p->pixels) {
 104                 png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
 105                 return 1;
 106         }
 107
 108         /* libpng reads by row, not by chunk, so we need row pointers to load to */
 109         row_pointers = alloca(sizeof(png_bytep)*height);
 110         if (!row_pointers) {
 111                 png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
 112                 free(p->pixels);
 113                 return 1;
 114         }
 115
 116         /* and this ensures the rows point to the correct place in the pixel data */
 117         for (i=0; i < height; ++i) {
 118                 row_pointers[i] = p->pixels + i * rowbytes;
 119         }
 120
 121         /* finally let libpng read everything in */
 122         png_read_image(png_ptr, row_pointers);
 123
 124         png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
 125
 126         /* check for a 32bit RGBA image */
 127         if (bpp != 4) {
 128                 /* convert 24bit RGB to 32bit RGBA */
 129                 if (bpp == 3) {
 130                         int j = 0;
 131                         int m = rowbytes*height;
 132                         unsigned char *px = p->pixels;
 133                         p->pixels = malloc(p->w*p->h*4);
 134                         for (i=0; i<m; i+=3) {
 135                                 p->pixels[j++] = px[i];
 136                                 p->pixels[j++] = px[i+1];
 137                                 p->pixels[j++] = px[i+2];
 138                                 p->pixels[j++] = 255;
 139                         }
 140                         free(px);
 141                 /* unsupported image */
 142                 }else{
 143                         vlprintf(CN_INFO, "PNG: unsupported image format: %dbpp",bpp);
 144                         free(p->pixels);
 145                         return 1;
 146                 }
 147         }
 148
 149         return 0;
 150 }
 151
 152 /* write pixel data to a png image */
 153 int image_save_png(image_t *p, char* file)
 154 {
 155         char buff[2048];
 156         FILE *f;
 157         int i;
 158         int rb;
 159         png_structp png_ptr;
 160         png_infop info_ptr;
 161         png_bytep *row_pointers;
 162
 163         if (!path_get(NULL,file,0,buff,2048))
 164                 return 1;
 165         f = fopen(buff,"wb");
 166         if (!f)
 167                 return 1;
 168
 169         png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING,NULL,NULL,NULL);
 170         if (!png_ptr) {
 171                 fclose(f);
 172                 return 1;
 173         }
 174
 175         /* Allocate/initialize the image information data.  REQUIRED */
 176         info_ptr = png_create_info_struct(png_ptr);
 177         if (!info_ptr) {
 178                 fclose(f);
 179                 png_destroy_write_struct(&png_ptr,  (png_infopp)NULL);
 180                 return 1;
 181         }
 182
 183         /* this is libpng's error handling, if something goes bad we'll
 184          * end up jumping back here where we can exit gracefullyish */
 185         if (setjmp(png_jmpbuf(png_ptr))) {
 186                 fclose(f);
 187                 png_destroy_write_struct(&png_ptr,  (png_infopp)NULL);
 188                 return 1;
 189         }
 190
 191         png_init_io(png_ptr, f);
 192
 193         png_set_compression_level(png_ptr, 9);
 194
 195         png_set_IHDR(
 196                 png_ptr,
 197                 info_ptr,
 198                 p->w,
 199                 p->h,
 200                 8,
 201                 PNG_COLOR_TYPE_RGB_ALPHA,
 202                 PNG_INTERLACE_NONE,
 203                 PNG_COMPRESSION_TYPE_BASE,
 204                 PNG_FILTER_TYPE_BASE
 205         );
 206
 207         /* Write the file header information */
 208         png_write_info(png_ptr, info_ptr);
 209
 210         /* create rows for later writing */
 211         row_pointers = alloca(sizeof(png_bytep)*p->h);
 212         rb = p->w*4;
 213         if (!row_pointers) {
 214                 png_destroy_write_struct(&png_ptr, (png_infopp)NULL);
 215                 return 1;
 216         }
 217
 218         /* and this ensures the rows point to the correct place in the pixel data */
 219         for (i=0; i<p->h; ++i) {
 220                 row_pointers[i] = p->pixels + (i * rb);
 221         }
 222         png_write_image(png_ptr, row_pointers);
 223
 224         png_write_end(png_ptr, info_ptr);
 225
 226         /* clean up */
 227         png_destroy_write_struct(&png_ptr, (png_infopp)NULL);
 228
 229         fclose(f);
 230
 231         return 0;
 232 }