/*****************************************************************
 * flextr.c: FBM Release 1.0 25-Feb-90 Michael Mauldin
 *
 * Copyright (C) 1989,1990 by Michael Mauldin.  Permission is granted
 * to use this file in whole or in part for any purpose, educational,
 * recreational or commercial, provided that this copyright notice
 * is retained unchanged.  This software is available to all free of
 * charge by anonymous FTP and in the UUNET archives.
 *
 * flextr.c: Extract a rectangle and/or resize it.
 *
 * CONTENTS
 *	extract_fbm (input, output, xo, yo, w, h, ow, oh, title, credits)
 *
 * EDITLOG
 *	LastEditDate = Mon Jun 25 17:03:19 1990 - Michael Mauldin
 *	LastFileName = /usr2/mlm/src/misc/fbm0.99/flextr.c
 *
 * HISTORY
 * 25-Jun-90  Michael Mauldin (mlm@cs.cmu.edu) Carnegie Mellon
 *	Package for Release 1.0
 *
 * 13-Jun-90  Michael Mauldin (mlm) at Carnegie Mellon University
 *	Final release (version 1.0) mlm@cs.cmu.edu
 *
 * 07-Mar-89  Michael Mauldin (mlm) at Carnegie Mellon University
 *	Beta release (version 0.9) mlm@cs.cmu.edu
 *
 * 12-Nov-88  Michael Mauldin (mlm) at Carnegie-Mellon University
 *	Created.
 *****************************************************************/

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

/****************************************************************
 * extract_fbm: Resize a bitmap
 *	copy input [xo:xo+w yo:yo+h] to output [ow oh]
 ****************************************************************/

#ifndef lint
static char *fbmid =
"$FBM flextr.c <1.0> 25-Jun-90  (C) 1989,1990 by Michael Mauldin, source \
code available free from MLM@CS.CMU.EDU and from UUNET archives$";
#endif

extract_fbm (input, output, xo, yo, w, h, ow, oh, title, credits)
FBM *input, *output;
int xo, yo, h, w, oh, ow;
char *title, *credits;
{ int k, rowlen;

  if ((w != ow || h != oh) && input->hdr.bits != 8)
  { fprintf (stderr,
	     "Can't resize images with %d bits per pixel\n", input->hdr.bits);
    return (0);
  }

  if (input->hdr.physbits != 8)
  { fprintf (stderr,
	     "Can't extract images with %d physbits per pixel\n",
	     input->hdr.physbits);
    return (0);
  }

  if (h < 1 || w < 1 || oh < 1 || ow < 1)
  { fprintf (stderr, "Extract: zero dimension [%dx%d] => [%dx%d]\n", 
	     w, h, ow, oh);
    return (0);
  }

  fprintf (stderr,
	   "Extract \"%s\" <%d,%d> [%dx%d] => [%dx%d] %d pixels\n",
	   title ? title : input->hdr.title[0] ? input->hdr.title : "untitled",
	   xo, yo, w, h, ow, oh, ow*oh);

  if (xo+w > input->hdr.cols)
  { fprintf (stderr, "Warning, input exceeds image horizontally\n");
    fprintf (stderr, "	xo %d, w %d, input->hdr.cols %d\n",
	     xo, w, input->hdr.cols);
  }
  if (yo+h > input->hdr.rows)
  { fprintf (stderr, "Warning, input exceeds image vertically\n");
    fprintf (stderr, "	yo %d, h %d, input->hdr.rows %d\n",
	     yo, h, input->hdr.rows);
  }

  /* Calculate length of row (pad to even byte boundary) */
  rowlen = 2 * ((ow * input->hdr.physbits + 15) / 16);
  
  /* Now build header for output bit map */
  output->hdr.cols = ow;
  output->hdr.rows = oh;
  output->hdr.planes = input->hdr.planes;
  output->hdr.bits = input->hdr.bits;
  output->hdr.physbits = input->hdr.physbits;
  output->hdr.rowlen = rowlen;
  output->hdr.plnlen = oh * output->hdr.rowlen;
  output->hdr.clrlen = input->hdr.clrlen;
  output->hdr.aspect = input->hdr.aspect * ow * h / (oh * w);

  if (title == NULL || *title == '\0')
  { strncpy (output->hdr.title, input->hdr.title, FBM_MAX_TITLE); }
  else
  { strcpy (output->hdr.title, title); }
    
  if (credits == NULL || *credits == '\0')
  { strncpy (output->hdr.credits, input->hdr.credits, FBM_MAX_TITLE); }
  else
  { strcpy (output->hdr.credits, credits); }
    
  /* Allocate space for output bits */
  alloc_fbm (output);

  copy_clr (input, output);

  /* Warning about resizing mapped image */
  if (input->hdr.clrlen > 0 && (w != ow || h != oh))
  { fprintf (stderr,
	     "Warning, %s\n         %s\n",
	     "resizing a mapped image is probably not what you want",
	     "I'll do it anyway, but you should probably use unmap first.");
  }

  /* Now extract each plane separately */
  for (k=0; k<output->hdr.planes; k++)
  { if (! extract_one (&(input->bm[k * input->hdr.plnlen]),
		       &(output->bm[k * output->hdr.plnlen]),
		       input->hdr.cols, input->hdr.rows,
		       input->hdr.rowlen, output->hdr.rowlen,
		       xo, yo, w, h, ow, oh))
    { free_fbm (output); return (0); }
  }

  return (1);
}

/****************************************************************
 * extract_one: Resize a bitmap
 *	copy input [xo:xo+w yo:yo+h] to output [ow oh]
 ****************************************************************/

extract_one (inbm, outbm, cols, rows, inlen, outlen, xo, yo, w, h, ow, oh)
unsigned char *inbm, *outbm;
int inlen, outlen, xo, yo, h, w, oh, ow;
{ register int xf, yf, xi, i; 
  register unsigned char *bm1, *bm2,  *obm;
  int j, yi, dc;

  /* Check for scale of 1-1, special case for speed */
  if (w == ow && h == oh && xo >= 0 && yo >= 0 && xo+w <= cols && yo+h <= rows)
  { for (j=0; j<h; j++)
    { bm1 = &inbm[(j+yo) * inlen];
      obm = &outbm[j * outlen];

      for (i=0; i<w; i++)
      { obm[i] = bm1[i + xo]; }
    }
  }
  else
  {    
    for (j = 0; j<oh; j++)
    { yi = (j*h / oh) + yo;
      yf = (j*h % oh);

      obm = &outbm[j * outlen];
      bm1 = &inbm[yi * inlen];
      bm2 = bm1 + inlen;

      for (i=0; i<ow; i++)
      { xi = (i*w / ow) + xo;
        xf = (i*w % ow);

	if (xi < 0 || yi < 0 ||
	    xi > cols-2 ||
	    yi > rows-2)
	{ static cntr = 0;

	  /* If right on edge, just use edge value */
	  if ((xi == cols-1 &&
	       yi >= 0 && yi <= rows-1) ||
	      (yi == rows-1 &&
	       xi >= 0 && xi <= cols-1))
	  { obm[i] = bm1[xi]; }
	  else
	  { obm[i] = 255;

	    if (cntr++ < 3)
	    { fprintf (stderr,
		       "i,j %d,%d => xi,yi %d,%d, out of bounds %d,%d\n",
		       i, j, xi, yi, cols, rows);
	      fprintf (stderr,
		       "w %d, h %d, ow %d, oh %d\n\n", 
		       w, h, ow, oh);
	    }  
	  }
        }
	else
	{ dc = ( bm1[xi]   * (ow-xf)*(oh-yf) + 
		 bm2[xi]   * (ow-xf)*(yf) + 
		 bm1[xi+1] * (xf)*(oh-yf) + 
		 bm2[xi+1] * (xf)*(yf) ) / (ow*oh);

	  if (dc < 0)		{ dc = 0; }
	  else if (dc > 255)	{ dc = 255; }

	  obm[i] = dc;
	}
      }
    }
  }

  return (1);
}