w3d/pnm.c

   1 /**
   2  *   Thanks to Simon who contributed the code to make these functions
   3  *   CR/LF safe !
   4  */
   5
   6 #include <string.h>
   7 #include <ctype.h>
   8
   9 #include "w3dtypes.h"
  10 #include "mem.h"
  11
  12
  13
  14 static
  15 int eat_ws_comments(FILE *fp)
  16 {
  17    int c;
  18
  19    while ((c = fgetc(fp)) != EOF) {
  20       if (c == '#') {                    /* eat the comment */
  21          do {
  22             c = fgetc(fp);
  23             if (c == EOF)                /* but bail if we hit EOF */
  24                return -1;
  25          } while (c != '\n');
  26       }
  27
  28       if (!isspace(c)) {                 /* we are done */
  29          return ungetc(c,fp);
  30       }
  31    }
  32
  33    return -1;  /* fell out of the loop */
  34 }
  35
  36
  37 /* this is a kludge, but raw pnm's are not well defined... */
  38 static
  39 int eat_ws_to_eol (FILE *fp)
  40 {
  41    int c;
  42
  43    do {
  44       c = fgetc(fp);
  45
  46       if (c == '\n' || c == '\r') /* some dos/win pnms generated with */
  47          return c;                /* just '\r' after maxval */
  48    } while (isspace(c));
  49
  50    return ungetc(c,fp);
  51 }
  52
  53
  54 static
  55 int read_pnm_header_internal (FILE *fp, int *w, int *h)
  56 {
  57    int type, maxval;
  58
  59    if (fgetc(fp) != 'P')
  60       return -1;
  61
  62    type = fgetc(fp) - '0';
  63
  64    if (type < 0 || type > 6)
  65       return -1;               /* invalid type */
  66
  67    eat_ws_comments(fp);
  68    fscanf(fp, "%d", w);
  69
  70    eat_ws_comments(fp);
  71    fscanf(fp, "%d", h);
  72
  73    eat_ws_comments(fp);
  74    fscanf(fp, "%d", &maxval);
  75    eat_ws_to_eol(fp);
  76
  77    return type;
  78 }
  79
  80
  81 int read_pnm_header (char *fname, int *w, int *h)
  82 {
  83    int type;
  84    FILE *fp = fopen(fname, "rb");
  85
  86    if (!fp)
  87       return -1;
  88
  89    type = read_pnm_header_internal (fp, w, h);
  90
  91    fclose (fp);
  92
  93    return (type == 3 || type == 6) ? 3 : 1;
  94 }
  95
  96
  97 int read_pnm (char *fname, uint8_t *buf)
  98 {
  99    FILE *fp = fopen(fname, "rb");
 100    int type;
 101    int w, h;
 102
 103    if (!fp)
 104       return -1;
 105
 106    type = read_pnm_header_internal (fp, &w, &h);
 107
 108    switch (type) {
 109    case 5:
 110       if (fread (buf, 1, w*h, fp) != w*h)
 111          return -1;
 112       break;
 113    case 6:
 114       if (fread (buf, 3, w*h, fp) != w*h)
 115          return -1;
 116       break;
 117    default:
 118       fprintf (stderr, "%s: unimplemented image format !!!\n", __FUNCTION__);
 119    };
 120
 121    fclose (fp);
 122
 123    return 0;
 124 }
 125
 126
 127 void write_pnm (char *fname, uint8_t *rgb, int w, int h)
 128 {
 129    FILE *outfile;
 130
 131    outfile = fopen (fname, "wb");
 132
 133    if (!outfile) {
 134       fprintf (stderr, "error opening '%s' for writing !!!\n", fname);
 135       exit (-1);
 136    }
 137
 138
 139    if (strstr(fname, ".ppm") == fname + strlen(fname)-4) {
 140       fprintf (outfile, "P6\n%d %d\n%d\n", w, h, 255);
 141       fwrite (rgb, 3, w*h, outfile);
 142    } else if (strstr(fname, ".pgm") == fname + strlen(fname)-4) {
 143       fprintf (outfile, "P5\n%d %d\n%d\n", w, h, 255);
 144       fwrite (rgb, 1, w*h, outfile);
 145    } else {
 146       fprintf (stderr,
 147                "%s: can't write anything else than .ppm's and .pgm's !\n",
 148                __FUNCTION__);
 149       exit (-1);
 150    }
 151
 152    fclose (outfile);
 153 }
 154
 155
 156 static inline
 157 uint8_t CLAMP(int16_t x)
 158 {
 159    return  ((x > 255) ? 255 : (x < 0) ? 0 : x);
 160 }
 161
 162
 163 void write_pgm16 (char *fname, int16_t *rgb, int w, int h, int16_t offset)
 164 {
 165    int i;
 166    FILE *outfile;
 167
 168    outfile = fopen (fname, "wb");
 169
 170    if (!outfile) {
 171       printf ("error opening '%s' for writing !!!\n", fname);
 172       exit (-1);
 173    }
 174
 175    fprintf (outfile, "P5\n%d %d\n%d\n", w, h, 255);
 176    for (i=0; i<w*h; i++) {
 177       uint8_t c = CLAMP(rgb[i] + offset);
 178       fwrite (&c, 1, 1, outfile);
 179    }
 180    fclose (outfile);
 181 }
 182
 183