Usenet 1994 January/usenetsourcesnewsgroupsinfomagicjanuary1994.iso/sources/unix/volume19/fbm/part04/flshrp.c

C/C++ Source or Header | 1989-06-08 | 5.2 KB | 204 lines

/*****************************************************************
 * flshrp.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.
 *
 * flshrp.c:
 *
 * CONTENTS
 *    sharpen_fbm (input, output, beta)
 *
 * EDITLOG
 *    LastEditDate = Tue Mar  7 19:57:30 1989 - Michael Mauldin
 *    LastFileName = /usr2/mlm/src/misc/fbm/flshrp.c
 *
 * HISTORY
 * 07-Mar-89  Michael Mauldin (mlm) at Carnegie Mellon University
 *    Beta release (version 0.9) [e-mail]
 *
 * 12-Nov-88  Michael Mauldin (mlm) at Carnegie-Mellon University
 *    Created.
 *****************************************************************/

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

/****************************************************************
 * sharpen_fbm: determine whether image is in color, and call the
 *            appropriate sharpening routine.
 ****************************************************************/

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

sharpen_fbm (input, output, beta)
FBM *input, *output;
double beta;
{
  if (input->hdr.planes == 1 && input->hdr.clrlen == 0)
  { return (sharpen_bw (input, output, beta)); }
  else
  { return (sharpen_clr (input, output, beta)); }
}

/****************************************************************
 * sharpen_bw: use a digital Laplacian filter to sharpen a BW image
 ****************************************************************/

sharpen_bw (input, output, beta)
FBM *input, *output;
double beta;
{ register unsigned char *bmp, *obm;
  register int i, j, rowlen, w, h, sum;
  int new, delta, beta100 = beta * 100;

  if (input->hdr.planes != 1)
  { fprintf (stderr, "sharpen_bw: can't sharpen color images\n");
    return (0);
  }

  fprintf (stderr, "Sharpen BW, beta %lg\n", beta);

  /* Allocate output */
  output->hdr = input->hdr;
  alloc_fbm (output);

  w = input->hdr.cols;
  h = input->hdr.rows;
  rowlen = input->hdr.rowlen;

  /* Copy edges directly */
  for (j=0; j<h; j++)
  { output->bm[j*rowlen] = input->bm[j*rowlen];
    output->bm[j*rowlen + w-1] = input->bm[j*rowlen + w-1];
  }

  for (i=0; i<w; i++)
  { output->bm[i] = input->bm[i];
    output->bm[(h-1)*rowlen + i] = input->bm[(h-1)*rowlen + i];
  }

  for (j=1; j < h-1; j++)
  { bmp = &(input->bm[j*rowlen]);
    obm = &(output->bm[j*rowlen]);

    for (i=1; i < w-1; i++)
    { sum = bmp[i-rowlen-1] +     bmp[i-rowlen] + bmp[i-rowlen+1] +
        bmp[i-1]        - 8 * bmp[i]        + bmp[i+1]        +
        bmp[i+rowlen-1] +     bmp[i+rowlen] + bmp[i+rowlen+1];

      if (sum < 0)
      { delta = - (beta100 * bmp[i] * -sum / (8*WHITE*100)); }
      else
      { delta = beta100 * bmp[i] * sum / (8*WHITE*100); }

      new = bmp[i] - delta;

      if (new < BLACK) new = BLACK;
      else if (new > WHITE) new = WHITE;

      obm[i] = new;
    }
  }

  return (1);
}

/****************************************************************
 * sharpen_clr: use a digital Laplacian filter to sharpen a CLR image
 ****************************************************************/

sharpen_clr (input, output, beta)
FBM *input, *output;
double beta;
{ register unsigned char *bmp, *obm, *avg;
  register int i, j, k, rowlen, plnlen, w, h, p, sum;
  int new, delta, beta100 = beta * 100;
  unsigned char *gray;

  if (input->hdr.clrlen > 0)
  { fprintf (stderr,
     "cannot sharpen mapped color images, use 'gray2clr -u' first\n");
    return (0);
  }

  fprintf (stderr, "Sharpen color, beta %lg\n", beta);

  /* Allocate output */
  output->hdr = input->hdr;
  alloc_fbm (output);

  w = input->hdr.cols;
  h = input->hdr.rows;
  p = input->hdr.planes;
  rowlen = input->hdr.rowlen;
  plnlen = input->hdr.plnlen;

  /* Calculate the intensity plane */
  gray = (unsigned char *) malloc (plnlen);

  for (j=0; j<h; j++)
  { bmp = &(input->bm[j*rowlen]);
    avg = &(gray[j*rowlen]);

    for (i=0; i<w; i++)
    { sum = 0;
      for (k=0; k<p; k++)
      { sum += bmp[i+k*plnlen]; }
      avg[i] = sum/p;
    }
  }

  /* Copy edges directly */
  for (k=0; k<p; k++)
  {  for (j=0; j<h; j++)
    { output->bm[k*plnlen + j*rowlen] =
    input->bm[k*plnlen + j*rowlen];
      output->bm[k*plnlen + j*rowlen + w-1] =
    input->bm[k*plnlen + j*rowlen + w-1];
    }

    for (i=0; i<w; i++)
    { output->bm[k*plnlen + i] =
    input->bm[k*plnlen + i];
      output->bm[k*plnlen + (h-1)*rowlen + i] =
    input->bm[k*plnlen + (h-1)*rowlen + i];
    }
  }

  for (j=1; j < h-1; j++)
  { avg = &(gray[j*rowlen]);

    for (i=1; i < w-1; i++)
    { sum = avg[i-rowlen-1] +     avg[i-rowlen] + avg[i-rowlen+1] +
        avg[i-1]        - 8 * avg[i]        + avg[i+1]        +
        avg[i+rowlen-1] +     avg[i+rowlen] + avg[i+rowlen+1];

      for (k=0; k<p; k++)
      { bmp =  &(input->bm[k*plnlen + j*rowlen + i]);
        obm = &(output->bm[k*plnlen + j*rowlen + i]);

    if (sum < 0)
    { delta = - (beta100 * *bmp * -sum / (8*WHITE*100)); }
    else
    { delta = beta100 * *bmp * sum / (8*WHITE*100); }

    new = *bmp - delta;

    if (new < BLACK) new = BLACK;
    else if (new > WHITE) new = WHITE;

    *obm = new;
      }
    }
  }

  return (1);
}