This is pnmshear.c in view mode; [Download] [Up]
/* pnmshear.c - read a portable anymap and shear it by some angle
**
** Copyright (C) 1989, 1991 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 <math.h>
#include "pnm.h"
#ifndef M_PI
#define M_PI 3.14159265358979323846
#endif /*M_PI*/
#define SCALE 4096
#define HALFSCALE 2048
int
main( argc, argv )
int argc;
char* argv[];
{
FILE* ifp;
xel* xelrow;
register xel* newxelrow;
register xel* xP;
register xel* nxP;
xel bgxel, prevxel;
int argn, rows, cols, format, newformat, newcols, row, col;
xelval maxval;
int antialias;
float fangle, shearfac, new0;
int intnew0;
register long fracnew0, omfracnew0;
char* usage = "[-noantialias] <angle> [pnmfile]";
pnm_init( &argc, argv );
argn = 1;
antialias = 1;
if ( argn < argc && argv[argn][0] == '-' && argv[argn][1] != '\0' &&
( argv[argn][1] < '0' || argv[argn][1] > '9' ) )
{
if ( pm_keymatch( argv[argn], "-antialias", 2 ) )
antialias = 1;
else if ( pm_keymatch( argv[argn], "-noantialias", 2 ) )
antialias = 0;
else
pm_usage( usage );
++argn;
}
if ( argn == argc )
pm_usage( usage );
if ( sscanf( argv[argn], "%f", &fangle ) != 1 )
pm_usage( usage );
++argn;
if ( fangle <= -90.0 || fangle >= 90.0 )
pm_error( "angle must be between -90 and 90" );
fangle = fangle * M_PI / 180.0; /* convert to radians */
shearfac = tan( fangle );
if ( shearfac < 0.0 )
shearfac = -shearfac;
if ( argn != argc )
{
ifp = pm_openr( argv[argn] );
++argn;
}
else
ifp = stdin;
if ( argn != argc )
pm_usage( usage );
pnm_pbmmaxval = PNM_MAXMAXVAL; /* use larger value for better results */
pnm_readpnminit( ifp, &cols, &rows, &maxval, &format );
xelrow = pnm_allocrow( cols );
/* Promote PBM files to PGM. */
if ( antialias && PNM_FORMAT_TYPE(format) == PBM_TYPE )
{
newformat = PGM_TYPE;
pm_message( "promoting from PBM to PGM - use -noantialias to avoid this" );
}
else
newformat = format;
newcols = rows * shearfac + cols + 0.999999;
pnm_writepnminit( stdout, newcols, rows, maxval, newformat, 0 );
newxelrow = pnm_allocrow( newcols );
bgxel = pnm_backgroundxelrow( xelrow, cols, maxval, format );
for ( row = 0; row < rows; ++row )
{
pnm_readpnmrow( ifp, xelrow, cols, maxval, format );
if ( fangle > 0.0 )
new0 = row * shearfac;
else
new0 = ( rows - row ) * shearfac;
intnew0 = (int) new0;
if ( antialias )
{
fracnew0 = ( new0 - intnew0 ) * SCALE;
omfracnew0 = SCALE - fracnew0;
for ( col = 0, nxP = newxelrow; col < newcols; ++col, ++nxP )
*nxP = bgxel;
prevxel = bgxel;
for ( col = 0, nxP = &(newxelrow[intnew0]), xP = xelrow; col < cols; ++col, ++nxP, ++xP )
{
switch ( PNM_FORMAT_TYPE(format) )
{
case PPM_TYPE:
PPM_ASSIGN( *nxP,
( fracnew0 * PPM_GETR(prevxel) + omfracnew0 * PPM_GETR(*xP) + HALFSCALE ) / SCALE,
( fracnew0 * PPM_GETG(prevxel) + omfracnew0 * PPM_GETG(*xP) + HALFSCALE ) / SCALE,
( fracnew0 * PPM_GETB(prevxel) + omfracnew0 * PPM_GETB(*xP) + HALFSCALE ) / SCALE );
break;
default:
PNM_ASSIGN1( *nxP,
( fracnew0 * PNM_GET1(prevxel) + omfracnew0 * PNM_GET1(*xP) + HALFSCALE ) / SCALE );
break;
}
prevxel = *xP;
}
if ( fracnew0 > 0 )
{
nxP = &(newxelrow[intnew0 + cols]);
switch ( PNM_FORMAT_TYPE(format) )
{
case PPM_TYPE:
PPM_ASSIGN( *nxP,
( fracnew0 * PPM_GETR(prevxel) + omfracnew0 * PPM_GETR(bgxel) + HALFSCALE ) / SCALE,
( fracnew0 * PPM_GETG(prevxel) + omfracnew0 * PPM_GETG(bgxel) + HALFSCALE ) / SCALE,
( fracnew0 * PPM_GETB(prevxel) + omfracnew0 * PPM_GETB(bgxel) + HALFSCALE ) / SCALE );
break;
default:
PNM_ASSIGN1( *nxP,
( fracnew0 * PNM_GET1(prevxel) + omfracnew0 * PNM_GET1(bgxel) + HALFSCALE ) / SCALE );
break;
}
}
}
else
{
for ( col = 0, nxP = newxelrow; col < intnew0; ++col, ++nxP )
*nxP = bgxel;
for ( col = 0, xP = xelrow; col < cols; ++col, ++nxP, ++xP )
*nxP = *xP;
for ( col = intnew0 + cols; col < newcols; ++col, ++nxP )
*nxP = bgxel;
}
pnm_writepnmrow( stdout, newxelrow, newcols, maxval, newformat, 0 );
}
pm_close( ifp );
pm_close( stdout );
exit( 0 );
}
These are the contents of the former NiCE NeXT User Group NeXTSTEP/OpenStep software archive, currently hosted by Netfuture.ch.