png.c

   1 /*
   2     fbv  --  simple image viewer for the linux framebuffer
   3     Copyright (C) 2000, 2001, 2003  Mateusz Golicz
   4
   5     This program is free software; you can redistribute it and/or modify
   6     it under the terms of the GNU General Public License as published by
   7     the Free Software Foundation; either version 2 of the License, or
   8     (at your option) any later version.
   9
  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 General Public License for more details.
  14
  15     You should have received a copy of the GNU General Public License
  16     along with this program; if not, write to the Free Software
  17     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  18 */
  19
  20 #include "config.h"
  21 #ifdef FBV_SUPPORT_PNG
  22 #include <png.h>
  23 #include "fbv.h"
  24 #include <sys/types.h>
  25 #include <sys/stat.h>
  26 #include <fcntl.h>
  27 #include <unistd.h>
  28 #include <stdlib.h>
  29 #include <string.h>
  30
  31 #define PNG_BYTES_TO_CHECK 4
  32 #ifndef min
  33 #define min(x,y) ((x) < (y) ? (x) : (y))
  34 #endif
  35
  36 int fh_png_id(char *name)
  37 {
  38     int fd;
  39     char id[4];
  40     fd=open(name,O_RDONLY); if(fd==-1) return(0);
  41     read(fd,id,4);
  42     close(fd);
  43     if(id[1]=='P' && id[2]=='N' && id[3]=='G') return(1);
  44     return(0);
  45 }
  46
  47
  48 int fh_png_load(char *name,unsigned char *buffer, unsigned char ** alpha,int x,int y)
  49 {
  50     png_structp png_ptr;
  51     png_infop info_ptr;
  52     png_uint_32 width, height;
  53     int i;
  54     int bit_depth, color_type, interlace_type;
  55     int number_passes,pass, trans = 0;
  56     char *rp;
  57     png_bytep rptr[2];
  58     char *fbptr;
  59     FILE *fh;
  60
  61     if(!(fh=fopen(name,"rb"))) return(FH_ERROR_FILE);
  62
  63     png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING,NULL,NULL,NULL);
  64     if (png_ptr == NULL) return(FH_ERROR_FORMAT);
  65     info_ptr = png_create_info_struct(png_ptr);
  66     if (info_ptr == NULL)
  67     {
  68         png_destroy_read_struct(&png_ptr, (png_infopp)NULL, (png_infopp)NULL);
  69         fclose(fh); return(FH_ERROR_FORMAT);
  70     }
  71     rp=0;
  72     if (setjmp(png_jmpbuf(png_ptr)))
  73     {
  74         png_destroy_read_struct(&png_ptr, &info_ptr, (png_infopp)NULL);
  75         if(rp) free(rp);
  76         fclose(fh); return(FH_ERROR_FORMAT);
  77     }
  78
  79     png_init_io(png_ptr,fh);
  80
  81     png_read_info(png_ptr, info_ptr);
  82     png_get_IHDR(png_ptr, info_ptr, &width, &height, &bit_depth, &color_type,&interlace_type, NULL, NULL);
  83     if (color_type == PNG_COLOR_TYPE_PALETTE) png_set_expand(png_ptr);
  84     if (bit_depth < 8) png_set_packing(png_ptr);
  85     if (color_type == PNG_COLOR_TYPE_GRAY || color_type== PNG_COLOR_TYPE_GRAY_ALPHA) png_set_gray_to_rgb(png_ptr);
  86         if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS))
  87         {
  88                 trans = 1;
  89                 png_set_tRNS_to_alpha(png_ptr);
  90         }
  91
  92     if(bit_depth == 16) png_set_strip_16(png_ptr);
  93     number_passes = png_set_interlace_handling(png_ptr);
  94     png_read_update_info(png_ptr,info_ptr);
  95
  96         if (color_type == PNG_COLOR_TYPE_GRAY_ALPHA || color_type == PNG_COLOR_TYPE_RGB_ALPHA || trans)
  97         {
  98                 unsigned char * alpha_buffer = (unsigned char*) malloc(width * height);
  99                 unsigned char * aptr;
 100
 101         rp = (char*) malloc(width * 4);
 102             rptr[0] = (png_bytep) rp;
 103
 104                 *alpha = alpha_buffer;
 105
 106             for (pass = 0; pass < number_passes; pass++)
 107         {
 108                         fbptr = (char *)buffer;
 109                         aptr = alpha_buffer;
 110
 111                         for(i=0; i<height; i++)
 112                 {
 113                                 int n;
 114                                 unsigned char *trp = (unsigned char *)rp;
 115
 116                         png_read_rows(png_ptr, rptr, NULL, 1);
 117
 118                                 for(n = 0; n < width; n++, fbptr += 3, trp += 4)
 119                                 {
 120                                         memcpy(fbptr, trp, 3);
 121                                         *(aptr++) = trp[3];
 122                                 }
 123                         }
 124         }
 125             free(rp);
 126         }
 127         else
 128         {
 129             for (pass = 0; pass < number_passes; pass++)
 130         {
 131                         fbptr = (char *)buffer;
 132                         for(i=0; i<height; i++, fbptr += width*3)
 133                 {
 134                             rptr[0] = (png_bytep) fbptr;
 135                         png_read_rows(png_ptr, rptr, NULL, 1);
 136                         }
 137         }
 138         }
 139     png_read_end(png_ptr, info_ptr);
 140     png_destroy_read_struct(&png_ptr, &info_ptr, (png_infopp)NULL);
 141     fclose(fh);
 142     return(FH_ERROR_OK);
 143 }
 144 int fh_png_getsize(char *name,int *x,int *y)
 145 {
 146     png_structp png_ptr;
 147     png_infop info_ptr;
 148     png_uint_32 width, height;
 149     int bit_depth, color_type, interlace_type;
 150     char *rp;
 151     FILE *fh;
 152
 153     if(!(fh=fopen(name,"rb"))) return(FH_ERROR_FILE);
 154
 155     png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING,NULL,NULL,NULL);
 156     if (png_ptr == NULL) return(FH_ERROR_FORMAT);
 157     info_ptr = png_create_info_struct(png_ptr);
 158     if (info_ptr == NULL)
 159     {
 160         png_destroy_read_struct(&png_ptr, (png_infopp)NULL, (png_infopp)NULL);
 161         fclose(fh); return(FH_ERROR_FORMAT);
 162     }
 163     rp=0;
 164     if (setjmp(png_jmpbuf(png_ptr)))
 165     {
 166         png_destroy_read_struct(&png_ptr, &info_ptr, (png_infopp)NULL);
 167         if(rp) free(rp);
 168         fclose(fh); return(FH_ERROR_FORMAT);
 169     }
 170
 171     png_init_io(png_ptr,fh);
 172     png_read_info(png_ptr, info_ptr);
 173     png_get_IHDR(png_ptr, info_ptr, &width, &height, &bit_depth, &color_type,&interlace_type, NULL, NULL);
 174     png_destroy_read_struct(&png_ptr, &info_ptr, (png_infopp)NULL);
 175     *x=width;
 176     *y=height;
 177     fclose(fh);
 178     return(FH_ERROR_OK);
 179 }
 180 #endif