/********************************************************************/
/** bbox -- calculates Bounding Box of a pbmraw/ppmraw-picture     **/
/** Created:   Nov. 1997, revised 1998, 1999, 2009, 2021           **/
/** Author:    Roland Bless <roland -at- bless.de>                 **/
/** Copyright (C) 1998-2020 Roland Bless                           **/
/** To compile simply use:                                         **/
/** "cc bbox.c -o bbox" or "make bbox"                             **/ 
/********************************************************************/
/*
 * $Id: bbox.c 146 2021-03-12 20:26:23Z bless $
 */

/**
* This program is free software; you can redistribute it and/or modify     
* it under the terms of the GNU General Public License as published by     
* the Free Software Foundation; either version 2 of the License, or        
* (at your option) any later version.                                      
*                                                                          
* This program is distributed in the hope that it will be useful,          
* but WITHOUT ANY WARRANTY; without even the implied warranty of           
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the            
* GNU General Public License for more details.                             
*                                                                           
* You should have received a copy of the GNU General Public License        
* along with this program; if not, write to the Free Software              
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*
**/

/* Quoting EPSF Spec:
   http://partners.adobe.com/public/developer/en/ps/5002.EPSF_Spec.pdf

   %!PS-Adobe-3.0 EPSF-3.0
   %%BoundingBox: llx lly urx ury

   The four arguments of the bounding box comment correspond to the
   lower-left (llx, lly) and upper-right (urx, ury) corners of the
   bounding box. They are expressed in the default PostScript
   coordinate system. For an EPS file, the bounding box is the smallest
   rectangle that encloses all the marks painted on the single page of
   the EPS file.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#if defined(_WIN32) && !defined(__CYGWIN__)
#include <io.h>	  /* needed for _setmode() */
#include <fcntl.h>
#endif

/**********************
*  global variables   *
**********************/
const char *const version= "$Rev: 146 $";
const char *const prgname= "bbox";

const double round_precision= 1e-6;
const short int inputlinelength= 1024;

unsigned char bitval[8]=
{
  1 << 7,
  1 << 6,
  1 << 5,
  1 << 4,
  1 << 3,
  1 << 2,
  1 << 1,
  1
};

unsigned int minus_one(const unsigned x) 
{
  return (x == 0) ? x : x-1;
}

unsigned int plus_one(const unsigned x) 
{
  return (x == (unsigned int) ~0U) ? x : x+1;
}

/***************************** readppm_and_calcbb ***********************
*	input: 	name, resolution, tight                         	*
*	output: 	- (stdout)           				*
*                                                                       *
*     	Reads a RAWPPM or RAWPBM picture file (name or STDIN) and       *
*       calculates its Bounding Box on-the-fly (line-by-line).          *
*                                                                       *
*       Parameters:                                                     *
*       name: name of the PBMRAW file or NULL (input from stdin)        *
*       resolution: Pixel per Inch (DPI)                                *
*       tight: boolean value, if false 1 Postscript Point is added to   *
               each Bounding Box parameter, otherwise the BB is tight   *
*       The Bounding Box is given in Postscript Points  (72 dots/inch)  *
*       and printed to stdout                                           *
************************************************************************/
/* calculate the bounding box in postscript points, given a resolution in dpi */
void readppm_and_calcbb(const char *name, 
                        const unsigned int resolution, 
                        const unsigned char tight)
{
	FILE 	*inputfile;
        char    inputline[inputlinelength];
        unsigned char magic_found= 0;
        int x,y,byte_x,i;
	const double pt_dpi_dbl= 72.0;
        unsigned int x_min, x_max, y_min, y_max;
        unsigned int llx, lly, urx, ury; /* bounding box */
        double       hllx, hlly, hurx, hury; /* hires bounding box */
        unsigned char   *image_row,	 /* ImageRow */
                        *tmpcolumnbytep;
        unsigned int 	width,height;	 /* Image Size	*/ 
        unsigned int    byte_width;
        unsigned char   colormax= 0;       /* max color value */
        unsigned int    ui_colormax= 0;    /* max color value */
        
 	if ( name == NULL ) 
        {
          inputfile = stdin;
          name = "- STDIN -";
	}
	else 	
        {
          inputfile = fopen(name,"r");
          if ( inputfile == NULL )
          {
            fprintf(stderr,"%s: ERROR -- could not open file %s\n", 
                    prgname, name);
            exit(1);
          }
        }
        /** check for magic number **/
        do 
        {
		if (fgets(inputline, inputlinelength, inputfile) == NULL) {
			fprintf(stderr,"%s: ERROR -- unexpected end of file %s\n", prgname, name);
			fclose(inputfile);
			exit(1);
		}
#ifdef DEBUG
          fprintf(stderr,"read:[%s]\n",inputline);
#endif
          if ( strcmp(inputline,"P4\n") == 0 )
          {
            magic_found= 4;
          }
          else
          if ( strcmp(inputline,"P6\n") == 0 )
          {
            magic_found= 6;
          }
        }
        while ( !feof(inputfile) && !magic_found );
        
        if ( !magic_found )
        {
          fprintf(stderr,"%s: ERROR -- %s is not in ppmraw or pbmraw format\n",
                  prgname, name);
	  fclose(inputfile);
	  exit(1);
        }
        /** skip comments **/
        do 
        {
	   if (fgets(inputline, inputlinelength, inputfile) == NULL) {
		   fprintf(stderr,"%s: ERROR -- unexpected end of file %s\n", prgname, name);
		   fclose(inputfile);
		   exit(1);
	   }
#ifdef DEBUG
          fprintf(stderr,"read:[%s]\n",inputline);
#endif
          if (*inputline == '#')
            continue;
          else
            break;
        }
        while ( !feof(inputfile) );
        /** read picture size: width, height **/
        sscanf(inputline,"%u %u",&width,&height);
        if ( magic_found == 6 ) /* PPM file has maximum color-component value */
        {
	  if (fgets(inputline, inputlinelength, inputfile) == NULL) {
		  fprintf(stderr,"%s: ERROR -- unexpected end of file %s\n", prgname, name);
		  fclose(inputfile);
		  exit(1);
	  }
	  sscanf(inputline,"%u",&ui_colormax);  
	  colormax = (unsigned char) ui_colormax; /* this is safer */
        }
#ifdef DEBUG
	fprintf(stderr,"\nreading picture: %s size X: %u Y: %u\n",name,width,height);
#endif
        x_min= width>0 ? width-1 : 0;
        x_max= 0; 
        y_min= height>0 ? height-1 : 0; 
        y_max= 0;
        if ( magic_found == 4 ) /* PBMRAW = Bitmap */
        { /** read raw pbmfile **/
          byte_width= width / 8;
          if (width % 8 != 0)
            byte_width++;
        }
        else /** assume ppm raw **/
        { 
          byte_width= width * 3; /* we have RGB, i.e. three bytes for each pixel */
        }
	/* 
	 * Now read a raster of Width * Height pixels, proceeding through the image in normal English reading order,
         * i.e., starting from top left then moving right 
	 */
	/* we allocate only one line */
        image_row= malloc(byte_width);
        if ( image_row )
        {
#if defined(_WIN32) && !defined(__CYGWIN__)  /* this is really braindead stuff for MSVC */
	  i= _setmode( _fileno(stdin), _O_BINARY);
	  if (i == -1)
	    fprintf(stderr,"%s: ERROR - Cannot set binary mode for STDIN\n");
#endif
          for (y= 0; y<height; y++) /* for every image row 0..height-1 */
          {
            if (fread(image_row, byte_width, 1, inputfile) != 1)
            {
              fprintf(stderr,"%s: WARNING -- fread incomplete - file %s seems to be corrupt\n", prgname, name);
              break;
            }
            tmpcolumnbytep= image_row;
            /* inspect this line from left to right */
            for (byte_x= 0; byte_x<byte_width; byte_x++,tmpcolumnbytep++)
            {
              if (*tmpcolumnbytep != colormax) /* there are pixels not white */
              {
                if (magic_found == 4)
                {
                  for (i= 0; i<8 ; i++)
                  {
                    if (*tmpcolumnbytep & bitval[i])
                    {
                      x= byte_x*8+i;
                      if ( x >= width ) break;
#ifdef DEBUG
                      printf("(row %04d, %04d): <not white>\n",y,x);
#endif
                    }
                  } /* end for */
                } /* end if magic_found 4 */
                else
                { /* assume PPM */
                  x= byte_x/3; /* we have 3 bytes per pixel */
#ifdef DEBUG
                      printf("(row %04d, col %04d) byte %04d: <not %d>\n",y,x,byte_x,colormax);
#endif
                }
                /* update bounding box */
                if ( x < x_min ) x_min= x;
                if ( x > x_max ) x_max= x;
                if ( y < y_min ) y_min= y;
                if ( y > y_max ) y_max= y;
#ifdef DEBUG
                printf("ymin,height:(%04d,%04d) xmin,width:(%04d,%04d)\n",
                       y_min,y_max,x_min,x_max);
#endif
		break;
              } /* if there are pixels not white */
            } /* end for byte_x */
            if ( byte_x != byte_width )
            { /* there was a pixel with no background color */
              tmpcolumnbytep= image_row+byte_width-1;
              /* inspect this line from the right */
              for (byte_x= byte_width-1; 
                   byte_x >= 0; 
                   byte_x--,tmpcolumnbytep--)
              {
                if ( *tmpcolumnbytep != colormax ) /* there are pixels not white */
                {
                  if ( magic_found == 4 )
                  {
                    for (i= 0; i<8 ; i++)
                    {
                      if ( *tmpcolumnbytep & bitval[i] )
                      {
                        x= byte_x*8+i;
                        if (x >= width) break;
#ifdef DEBUG
                        printf("(%04d,%04d): <not white>\n",y,x);
#endif
                      }
                    } /* end for */
                  } /* end if magic_found 4 */
                  else
                  { /* assume PPM */
                    x= byte_x/3; /* we have 3 bytes per pixel */
                  }
                  /* update bounding box */
                  if ( x < x_min ) x_min= x;
                  if ( x > x_max ) x_max= x;
                  if ( y < y_min ) y_min= y;
                  if ( y > y_max ) y_max= y;
#ifdef DEBUG
                printf("ymin,height:(%04d,%04d) xmin,width:(%04d,%04d)\n",
                       y_min,y_max,x_min,x_max);
#endif
                  break;
                } /* if there are pixels not white */ 
              } /* end for byte_x */
            } /* if line contained not only background color */
          } /* end for y */
#ifdef DEBUG_BOX
          fprintf(stderr,"(%04d,%04d), (%04d,%04d)\n", x_min,height-y_max,x_max,height-y_min);
#endif
            /* distance from the left edge to the leftmost point */
            hllx= (x_min*pt_dpi_dbl)/resolution;
            /* distance from the bottom edge to the bottommost point */
            hlly= ((minus_one(height)-y_max)*pt_dpi_dbl)/resolution;
            /* distance from the left edge to the righmost point  */ 
	    hurx= (plus_one(x_max)*pt_dpi_dbl)/resolution;
            /* distance from the bottom edge to the uppermost point */
            hury= ((height-y_min)*pt_dpi_dbl)/resolution;


          if ( !tight )
          {
            /* distance from the left edge to the leftmost point */
            llx= minus_one((unsigned int) ((unsigned long) x_min*72UL)/resolution);
            /* distance from the bottom edge to the bottommost point */
            lly= minus_one((unsigned int) ((unsigned long) (minus_one(height)-y_max)*72UL)/resolution);
            /* distance from the left edge to the righmost point  */ 
            urx= plus_one((unsigned int) ((unsigned long) plus_one(x_max)*72UL)/resolution);
            /* distance from the bottom edge to the uppermost point */
            ury= plus_one((unsigned int) ((unsigned long) (height-y_min)*72UL)/resolution);

	    /* also loosen hires BBox by default precision */
	    if (hllx-round_precision >= 0.0)
		    hllx-=  round_precision;
	    if (hlly-round_precision >= 0.0)
		    hlly-=  round_precision;

	    hurx+=  round_precision;
	    hury+=  round_precision;
          }
          else /* tight bounding box */
          {
            /* distance from the left edge to the leftmost point */
            llx= (unsigned int) ((unsigned long) x_min*72UL)/resolution;
            /* distance from the bottom edge to the bottommost point */
            lly= (unsigned int) ((unsigned long) (minus_one(height)-y_max)*72UL)/resolution;
            /* distance from the left edge to the righmost point  */ 
            urx= (unsigned int) ((unsigned long) plus_one(x_max)*72UL)/resolution;
	    /* round up if we got a remainder */
            if ( (((unsigned long) plus_one(x_max)*72UL) % resolution) != 0 )
              urx= plus_one(urx);
            /* distance from the bottom edge to the uppermost point */
            ury= (unsigned int) ((unsigned long) (height-y_min)*72UL)/resolution;
            if ( (((unsigned long) (height-y_min)*72UL) % resolution) != 0 )
              ury= plus_one(ury);
          }
          /* skip the rest of the file if any data is still present */
          while ( !feof(inputfile) )
          {
            fgets(inputline, inputlinelength, inputfile);
          }

          /* give out Bounding Box */
          printf("%%%%BoundingBox: %d %d %d %d\n", llx, lly, urx, ury);
          printf("%%%%HiResBoundingBox: %f %f %f %f\n", hllx, hlly, hurx, hury);
        }
        else
          fprintf(stderr,"%s: ERROR -- not enough memory to read in one row of the picture\n", prgname);
        
	fclose(inputfile);
        free(image_row);
}


int	
main(int argc, char **argv)
{ 
  int i;
  char *filename= NULL;
  unsigned int resolution= 72; /* use 72 dpi as default resolution */
  unsigned char tight= 1;

  for (i= 1; i<argc; i++)
  {
    if ( strcmp(argv[i],"-r") == 0 )
    {
      if (++i<argc)
        resolution= atol(argv[i]);
      else
        fprintf(stderr,"%s: ERROR -- Missing resolution after -r\n",prgname);
    }
    else
    if ( strcmp(argv[i],"-l") == 0 )
    {
      tight= 0;
    }
    else
    if ( strcmp(argv[i],"-V") == 0 || strcmp(argv[i],"--version")==0 )
    {
      printf("%s: bbox Version %s\n",prgname,version);
      return 0;
    }
    else
    if ( strcmp(argv[i],"-h")==0 || strcmp(argv[i],"--help")==0 )
    {
      printf("%s: Version %s\n",prgname,version);
      printf(" usage: %s [-l] [-r resolution] [-V] [filename]\n",prgname);
      printf(" -l: loose bounding box (bbox is expanded by 1 point)\n");
      printf(" -r: resolution of picture in dpi\n");
      printf(" -V: version information\n");
      printf(" -h: this help\n");
      printf(" bbox reads a rawppm or rawpbm file and prints out the\n");
      printf(" bounding box of the image. If no filename is specified\n");
      printf(" input is read from standard input.\n");
      return 0;
    }
    else
    if ( argv[i][0] == '-' ) /* unkown option */
    {
      fprintf(stderr,"%s: ERROR -- unknown option %s\n call %s -h for help on usage\n",
             prgname, argv[i], prgname);
      return 1;
    }
    else /* filename argument */
      filename= argv[i];
  }

  readppm_and_calcbb(filename, resolution, tight);

  return 0;
}