/* pnmflip.c - perform one or more flip operations on a portable anymap
**
** Copyright (C) 1989 by Jef Poskanzer.
**
** Permission to use, copy, modify, and distribute this software and its
** documentation for any purpose and without fee is hereby granted, provided
** that the above copyright notice appear in all copies and that both that
** copyright notice and this permission notice appear in supporting
** documentation.  This software is provided "as is" without express or
** implied warranty.
*/

#include <stdio.h>
#ifdef	SYSV
#include <string.h>
#else	SYSV
#include <strings.h>
#endif	SYSV
#include "pnm.h"

#define max(a,b) ((a) > (b) ? (a) : (b))

main( argc, argv )
int argc;
char *argv[];
    {
    FILE *ifd;
    xel **xels, **transpose();
    void leftright(), topbottom();
    int argn, rows, cols, format;
    xelval maxval;
    char *usage = "[-leftright|-lr] [-topbottom|-tb] [-transpose|-xy]\n            [-rotate90|-r90|-ccw] [-rotate270|r270|-cw]\n            [-rotate180|-r180] [pnmfile]";

    pm_progname = argv[0];

    argn = 1;

    /* Just check the validity of arguments here. */
    while ( argn < argc && argv[argn][0] == '-' )
	{
	if ( strncmp(argv[argn],"-lr",max(strlen(argv[argn]),2)) == 0 ||
	     strncmp(argv[argn],"-leftright",max(strlen(argv[argn]),2)) == 0 )
	    { }
	else if ( strncmp(argv[argn],"-tb",max(strlen(argv[argn]),3)) == 0 ||
	     strncmp(argv[argn],"-topbottom",max(strlen(argv[argn]),3)) == 0 )
	    { }
	else if ( strncmp(argv[argn],"-xy",max(strlen(argv[argn]),2)) == 0 ||
	     strncmp(argv[argn],"-transpose",max(strlen(argv[argn]),3)) == 0 )
	    { }
	else if ( strncmp(argv[argn],"-r90",max(strlen(argv[argn]),3)) == 0 ||
	     strncmp(argv[argn],"-rotate90",max(strlen(argv[argn]),8)) == 0 ||
	     strncmp(argv[argn],"-ccw",max(strlen(argv[argn]),3)) == 0 )
	    { }
	else if ( strncmp(argv[argn],"-r270",max(strlen(argv[argn]),3)) == 0 ||
	     strncmp(argv[argn],"-rotate270",max(strlen(argv[argn]),8)) == 0 ||
	     strncmp(argv[argn],"-cw",max(strlen(argv[argn]),3)) == 0 )
	    { }
	else if ( strncmp(argv[argn],"-r180",max(strlen(argv[argn]),3)) == 0 ||
	     strncmp(argv[argn],"-rotate180",max(strlen(argv[argn]),8)) == 0 )
	    { }
	else
	    pm_usage( usage );
	argn++;
	}

    if ( argn != argc )
	{
	ifd = pm_openr( argv[argn] );
	argn++;
	}
    else
	ifd = stdin;

    if ( argn != argc )
	pm_usage( usage );

    xels = pnm_readpnm( ifd, &cols, &rows, &maxval, &format );
    pm_close( ifd );

    /* Now go through the flags again, this time executing them. */
    argn = 1;
    while ( argn < argc && argv[argn][0] == '-' )
	{
	if ( strncmp(argv[argn],"-lr",max(strlen(argv[argn]),2)) == 0 ||
	     strncmp(argv[argn],"-leftright",max(strlen(argv[argn]),2)) == 0 )
	    leftright( xels, rows, cols );
	else if ( strncmp(argv[argn],"-tb",max(strlen(argv[argn]),3)) == 0 ||
	     strncmp(argv[argn],"-topbottom",max(strlen(argv[argn]),3)) == 0 )
	    topbottom( xels, rows, cols );
	else if ( strncmp(argv[argn],"-xy",max(strlen(argv[argn]),2)) == 0 ||
	     strncmp(argv[argn],"-transpose",max(strlen(argv[argn]),3)) == 0 )
	    xels = transpose( xels, &rows, &cols );
	else if ( strncmp(argv[argn],"-r90",max(strlen(argv[argn]),3)) == 0 ||
	     strncmp(argv[argn],"-rotate90",max(strlen(argv[argn]),8)) == 0 ||
	     strncmp(argv[argn],"-ccw",max(strlen(argv[argn]),3)) == 0 )
	    {
	    xels = transpose( xels, &rows, &cols );
	    topbottom( xels, rows, cols );
	    }
	else if ( strncmp(argv[argn],"-r270",max(strlen(argv[argn]),3)) == 0 ||
	     strncmp(argv[argn],"-rotate270",max(strlen(argv[argn]),8)) == 0 ||
	     strncmp(argv[argn],"-cw",max(strlen(argv[argn]),3)) == 0 )
	    {
	    xels = transpose( xels, &rows, &cols );
	    leftright( xels, rows, cols );
	    }
	else if ( strncmp(argv[argn],"-r180",max(strlen(argv[argn]),3)) == 0 ||
	     strncmp(argv[argn],"-rotate180",max(strlen(argv[argn]),8)) == 0 )
	    {
	    leftright( xels, rows, cols );
	    topbottom( xels, rows, cols );
	    }
	else
	    pm_error( "shouldn't happen!", 0,0,0,0,0 );
	argn++;
	}

    /* All done. */
    pnm_writepnm( stdout, xels, cols, rows, maxval, format );

    exit( 0 );
    }

void
leftright( xels, rows, cols )
xel **xels;
int rows, cols;
    {
    int row;
    register int col;
    register xel *x1P, *x2P;
    xel p;

    for ( row = 0; row < rows; row++ )
        for ( col = 0, x1P = xels[row], x2P = &(xels[row][cols-1]);
	      col < cols / 2;
	      col++, x1P++, x2P-- )
	    {
	    p = *x1P;
	    *x1P = *x2P;
	    *x2P = p;
	    }
    }

void
topbottom( xels, rows, cols )
xel **xels;
int rows, cols;
    {
    int row;
    register int col;
    register xel *x1P, *x2P;
    xel p;

    for ( row = 0; row < rows / 2; row++ )
        for ( col = 0, x1P = xels[row], x2P = xels[rows - 1 - row];
	      col < cols;
	      col++, x1P++, x2P++ )
	    {
	    p = *x1P;
	    *x1P = *x2P;
	    *x2P = p;
	    }
    }

xel **
transpose( xels, rowsP, colsP )
xel **xels;
int *rowsP, *colsP;
    {
    int row, t;
    register int col;
    register xel **newxels, *xP;

    newxels = pnm_allocarray( *rowsP, *colsP );	/* note parameter reversal */

    for ( row = 0; row < *rowsP; row++ )
        for ( col = 0, xP = xels[row]; col < *colsP; col++, xP++ )
	    newxels[col][row] = *xP;	/* reversal here too */
    
    pnm_freearray( xels, *rowsP );
    t = *rowsP;
    *rowsP = *colsP;
    *colsP = t;

    return newxels;
    }