Usenet 1994 October/usenetsourcesnewsgroupsinfomagicoctober1994disk2.iso/unix/volume19/fbm/part03/fbnorm.c

C/C++ Source or Header | 1989-06-08 | 5KB | 176 lines

/*****************************************************************
 * fbnorm.c: FBM Library 0.9 (Beta test) 07-Mar-89  Michael Mauldin
 *
 * Copyright (C) 1989 by Michael Mauldin.  Permission is granted to
 * use this file in whole or in part provided that you do not sell it
 * for profit and that this copyright notice is retained unchanged.
 *
 * fbnorm.c: Normalize contrast and brightness of image
 *
 * USAGE
 *      % fbnorm < image > image2
 *
 * EDITLOG
 *      LastEditDate = Tue Mar  7 19:56:35 1989 - Michael Mauldin
 *      LastFileName = /usr2/mlm/src/misc/fbm/fbnorm.c
 *
 * HISTORY
 * 07-Mar-89  Michael Mauldin (mlm) at Carnegie Mellon University
 *    Beta release (version 0.9) [e-mail]
 *
 * 21-Aug-88  Michael Mauldin (mlm) at Carnegie-Mellon University
 *      Created.
 *****************************************************************/

# include <stdio.h>
# include <math.h>
# include <ctype.h>
# include "fbm.h"

# define USAGE \
    "Usage: fbnorm [ -b<val> -w<val> ] [ -<type> ] < image > image"

#ifndef lint
static char *fbmid =
    "$FBM fbnorm.c <0.9> 07-Mar-89  (C) 1989 by Michael Mauldin$";
#endif

main (argc, argv)
char *argv[];
{ FBM image;
  register unsigned char *bmptr, *tail;
  register int j, k, ch, size, cnt;
  int min = -1, max = -1, cutoff;
  int hist[BYTE];
  double blackp = -1.0, whitep = -1.0;    /* Percent */
  int outtype = FMT_FBM;

  /* Get the options */
  while (--argc > 0 && (*++argv)[0] == '-')
  { while (*++(*argv))
    { switch (**argv)
      { case 'b':       blackp = atof (*argv+1); SKIPARG; break;
        case 'w':       whitep = atof (*argv+1); SKIPARG; break;
    case 'A':    outtype = FMT_ATK; break;
    case 'B':    outtype = FMT_FACE; break;
    case 'F':    outtype = FMT_FBM; break;
    case 'G':    outtype = FMT_GIF; break;
    case 'I':    outtype = FMT_IFF; break;
    case 'L':    outtype = FMT_LEAF; break;
    case 'M':    outtype = FMT_MCP; break;
    case 'P':    outtype = FMT_PBM; break;
    case 'S':    outtype = FMT_SUN; break;
    case 'T':    outtype = FMT_TIFF; break;
    case 'X':    outtype = FMT_X11; break;
    case 'Z':    outtype = FMT_PCX; break;
        default:        fprintf (stderr, "%s\n", USAGE);
                        exit (1);
      }
    }
  }

  if (argc == 1)
  { blackp = whitep = atof (argv[0]); }
  else if (argc == 2)
  { min = atoi (argv[0]); max = atoi (argv[1]); }
  else if (argc > 2)
  { fprintf (stderr, "%s\n", USAGE);
    exit (1);
  }

  /* Clear the memory pointer so alloc_fbm won't be confused */
  image.cm  = image.bm  = (unsigned char *) NULL;

  /* Now read in the image */
  if (read_bitmap (&image, (char *) NULL))
  {
    /* Check input type */
    if (image.hdr.physbits != 8)
    { fprintf (stderr,
           "Can't resize images with %d physical bits per pixel\n",
           image.hdr.physbits);
      exit (1);
    }

    /* Set default tail sizes */
    if (image.hdr.planes > 1)        /* Color defaults */
    { if (blackp < 0.0) blackp = 0.5;
      if (whitep < 0.0) whitep = 0.5;
    }
    else                /* Bw defaults */
    { if (blackp < 0.0) blackp = 2.0;
      if (whitep < 0.0) whitep = 1.0;
    }

    size = image.hdr.rows * image.hdr.cols * image.hdr.planes;

    /* Calculate min and max (if not given as arguments) */
    if (min < 0 || max < 0)
    {
      /* Compute histogram */
      for (ch=0; ch<BYTE; ch++)
      { hist[ch] = 0; }

      for (k=0; k<image.hdr.planes; k++)
      { for (j=0; j< image.hdr.rows; j++)
        { bmptr = &(image.bm[k*image.hdr.plnlen + j*image.hdr.rowlen]);
          tail = bmptr + image.hdr.cols;

          while (bmptr < tail)
          { hist[*bmptr++]++; }
        }
      }

      /* Take off 'blackp' percent of darkest pixels */
      cutoff = size * blackp / 100.0;

      for (ch=0, cnt=0; ch<BYTE; ch++)
      { if ((cnt += hist[ch]) > cutoff)
        { min = ch; break; }
      }

      /* Take off 'whitep' percent of darkest pixels */
      cutoff = size * whitep / 100.0;

      for (ch = BYTE-1, cnt=0; ch >= 0; ch--)
      { if ((cnt += hist[ch]) > cutoff)
        { max = ch; break; }
      }
    }

    fprintf (stderr, "Normalizing: \"%s\" <%d,%d> ==> <0..255>\n",
             image.hdr.title[0] ? image.hdr.title : "(untitled)", min, max);

    bmptr = image.bm;
    tail = bmptr+size;

    while (bmptr < tail)
    { ch = *bmptr;

      if (ch <= min)
      { ch = 0; }
      else if (ch >= max)
      { ch = 255; }
      else
      { ch = (ch - min) * 255 / (max - min); }

       if (ch < 0 || ch > 255)
       { fprintf (stderr, "raw %d, min %d, max %d, out %d\n",
                  *bmptr, min, max, ch);
       }

      *bmptr++ = ch;
    }

    /* The image is now an 8bit per pixel image */
    image.hdr.bits = 8;

    /* Write it out */
    write_bitmap (&image, stdout, outtype);
  }
  else
  { exit (1); }

  exit (0);
}