From arne%SFD.UIT.NO@VM1.NoDak.EDU Sun Apr 22 20:02:03 1990
Date:         Sun, 22 Apr 90 19:59:59 met
Reply-To: HP-48 -  HP-48sx Hand Held System <HP-48@VM1.NoDak.EDU>
Sender: HP-48 -  HP-48sx Hand Held System <HP-48@VM1.NoDak.EDU>
From: Arne Helme <arne%SFD.UIT.NO@VM1.NoDak.EDU>
To: Multiple recipients of list HP-48 <HP-48@NDSUVM1>

Hello HP48sx users !
This is a little hack I wrote to convert GROB's into portable bitmaps.
It takes input from stdin or a file and writes to stdout (UNIX !).
You can convert a portable bitmap into many other interesting formats
using the pbmplus package (referenced below). Please report bugs or
improvements.

-- Arne Helme (E-mail : arne@sfd.uit.no)

/* -*-C-*-
********************************************************************************
*
* File:         grob2pbm.c
* RCS:          $Header: $
* Description:  HP48sx ASCII GROB format to PBM (portable bitmap)
* Author:       Arne Helme
* Created:      Fri Mar 30 09:12:31 1990
* Modified:     Sun Apr 22 15:20:34 1990 (Arne Helme) arne@dstud2
* Language:     C
* Package:      N/A
* Status:       Experimental (Do Not Distribute)
*
* (c) Copyright 1990, arne@sfd.uit.no, all rights reserved.
*
********************************************************************************
*/

/*
  DESCRIPTION

      This program converts a HP48sx ASCII GROB file into a portable bitmap.
  Export your HP48sx GROBs to your computer, convert them to your favorite
  format and use them in your documents.
  The portable bitmap (PBM) is a interchange format in the Extended Portable
  Bitmap Toolkit written by Mr. Jef Poskanzer and the
  PBM software is public domain.

  STATUS

      A two hour's hack.

  KNOWN BUGS

      Wont take binary GROBS yet. Only tested on UNIX systemV machines.

  NOTE

      A public domain PBM package is available via anonymous ftp to
      sfd.uit.no [128.39.60.50] (pub/X11/pbmplus.tar.Z).
*/

#include <stdio.h>

#define GROB_MAGIC       "GROB"
#define PBM_MAGIC        "P1"
#define SPACE            ' '
#define NEWLINE          '\n'
#define ZERO             '0'
#define ONE              '1'
#define TRANSLATE        '%'
#define HP48sxHEADERSIZE 25
#define MAXLINE          64
#define ASCIISIZE        (int)((width / 4) + 1) * height

void convert (nibble, num)
int *nibble, num;
{
    int i;

    for (i = 0; i < num; i++) {
	*nibble & 1 ? fputc (ONE, stdout) : fputc (ZERO, stdout);
	fputc (SPACE, stdout);
	*nibble >>= 1;
    }
}

void main(argc, argv)
int argc;
char *argv[];
{

    FILE *fp;                       /* File pointer for reading GROB data */
    char  header[HP48sxHEADERSIZE]; /* GROB header                        */
    int   ch;                       /* Temporary character                */
    int   width;                    /* GROB width                         */
    int   height;                   /* GROB height                        */
    int   nibble1, nibble2;         /* Each containing a 4 bit nibble     */
    int   i, count, line = 0;       /* Loop and control registers         */

    /* Parse command line */
    switch (argc) {
    case 1:
	/* We'll have to read from stdin */
	fp = stdin;
	break;
    case 2:
	/* Program started with one argument, assume it is a filename */
	fp = fopen (argv[1], "r");
	if (fp == (FILE *)NULL) {
	    fprintf (stderr, "%s : unable to read file %s\n",
		     argv[0], argv[1]);
	    exit (1);
	}
	break;
    default :
	/* Unable to parse command line */
	fprintf (stderr, "Usage : %s <GROBfile>\n", argv[0]);
	exit (1);
    }

    /* Skip HP48sx translation information if any */
    if ((ch = fgetc(fp)) == EOF) {
	fprintf (stderr, "%s : unexpected end-of-file found\n",
		 argv[0]);
	exit (1);
    }

    if (ch == TRANSLATE) {
	if (fgets (header, HP48sxHEADERSIZE, fp) == NULL) {
	    fprintf (stderr, "%s : error reading HP48sx header\n", argv[0]);
	    exit (1);
	}
    } else
	ungetc (ch, fp);

    if (fscanf (fp, "%s", header) != 1) {
	fprintf (stderr, "%s : error reading GROB magic number\n", argv[0]);
	exit (1);
    }

    if (strcmp(header, GROB_MAGIC)) {
	fprintf (stderr, "%s : bad magic number\n", argv[0]);
	exit (1);
    }

    if (fscanf (fp, "%d %d", &width, &height) != 2) {
	fprintf (stderr, "%s : unable to read GROB size\n", argv[0]);
	exit (1);
    }

    /* Print new magic number and sizes to stdout */
    printf ("%s\n%d %d\n", PBM_MAGIC, width, height);

    /* Skip blank if any*/
    if ((ch =fgetc(fp)) != ' ')
	ungetc (ch, fp);

    /* Convert GROB data to PBM data */
    for (i=0; i < height; i++) {
	count = width;
	do {
	    /* Scan in two four-bit nibbles (one byte) */
	    fscanf (fp, "%1X%1X", &nibble1, &nibble2);

	    /* Check if we are in the last bits of current line */
	    if (count >= 8) {
		/* Convert 1st 4 bit nibble */
		convert (&nibble1, 4);

		/* Convert 2nd 4 bit nibble */
		convert (&nibble2, 4);
	    } else { /* Last bits, watch out for padded bits */

		/* check if we have a complete 1st four bit nibble */
		if (count >= 4) {
		    convert (&nibble1, 4);
		    convert (&nibble2, count - 4);
		} else
		    convert (&nibble1, count);
	    }

	    /* PBM wont't take lines longer than 70 chars, insert newline */
	    line += 16;
	    if (!(line % MAXLINE))
		fputc (NEWLINE, stdout);
	} while ((count -= 8) > 0);
    }
    fclose (stdout);
}