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/* pgmnorm.c - read a portable graymap and normalize the contrast
**
** 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 "pgm.h"
static int hist[PGM_MAXMAXVAL+1];
int
main( argc, argv )
int argc;
char* argv[];
{
FILE* ifp;
gray maxval;
gray** grays;
gray* grayrow;
register gray* gP;
int argn, rows, cols, format, row;
register int col;
int i, size, cutoff, count, val;
float bpercent, wpercent;
int bvalue, wvalue, range;
int specbpercent, specbvalue, specwpercent, specwvalue;
char* usage = "[-bpercent N | -bvalue N] [-wpercent N | -wvalue N] [pgmfile]";
pgm_init( &argc, argv );
argn = 1;
bpercent = 2.0;
wpercent = 1.0;
specbpercent = specbvalue = specwpercent = specwvalue = 0;
while ( argn < argc && argv[argn][0] == '-' && argv[argn][1] != '\0' )
{
if ( pm_keymatch( argv[argn], "-bpercent", 3 ) )
{
if ( specbvalue )
pm_error( "only one of -bpercent and -bvalue may be specified" );
++argn;
if ( argn == argc || sscanf( argv[argn], "%f", &bpercent ) != 1 )
pm_usage( usage );
if ( bpercent < 0.0 || bpercent > 100.0 )
pm_error( "black percentage must between 0 and 100" );
specbpercent = 1;
}
else if ( pm_keymatch( argv[argn], "-bvalue", 3 ) )
{
if ( specbpercent )
pm_error( "only one of -bpercent and -bvalue may be specified" );
++argn;
if ( argn == argc || sscanf( argv[argn], "%d", &bvalue ) != 1 )
pm_usage( usage );
if ( bvalue < 0 )
pm_error( "black value must be >= 0" );
specbvalue = 1;
}
else if ( pm_keymatch( argv[argn], "-wpercent", 3 ) )
{
if ( specwvalue )
pm_error( "only one of -wpercent and -wvalue may be specified" );
++argn;
if ( argn == argc || sscanf( argv[argn], "%f", &wpercent ) != 1 )
pm_usage( usage );
if ( wpercent < 0.0 || wpercent > 100.0 )
pm_error( "white percentage must be between 0 and 100" );
specwpercent = 1;
}
else if ( pm_keymatch( argv[argn], "-wvalue", 3 ) )
{
if ( specwpercent )
pm_error( "only one of -wpercent and -wvalue may be specified" );
++argn;
if ( argn == argc || sscanf( argv[argn], "%d", &wvalue ) != 1 )
pm_usage( usage );
if ( wvalue < 0 )
pm_error( "white value must be >= 0" );
specwvalue = 1;
}
else
pm_usage( usage );
++argn;
}
if ( argn < argc )
{
ifp = pm_openr( argv[argn] );
++argn;
}
else
ifp = stdin;
if ( argn != argc )
pm_usage( usage );
if ( specbvalue && specwvalue )
{
/* Rescale so that bvalue maps to 0, wvalue maps to maxval. */
pgm_readpgminit( ifp, &cols, &rows, &maxval, &format );
grayrow = pgm_allocrow( cols );
pgm_writepgminit( stdout, cols, rows, maxval, 0 );
for ( i = 0; i <= bvalue; ++i )
hist[i] = 0;
for ( i = wvalue; i <= maxval; ++i )
hist[i] = maxval;
range = wvalue - bvalue;
for ( i = bvalue+1, val = maxval; i < wvalue; ++i, val += maxval )
hist[i] = val / range;
for ( row = 0; row < rows; ++row )
{
pgm_readpgmrow( ifp, grayrow, cols, maxval, format );
for ( col = 0, gP = grayrow; col < cols; ++col, ++gP )
*gP = hist[*gP];
pgm_writepgmrow( stdout, grayrow, cols, maxval, 0 );
}
pm_close( ifp );
}
else
{
grays = pgm_readpgm( ifp, &cols, &rows, &maxval );
pm_close( ifp );
/* Build histogram. */
for ( i = 0; i <= maxval; ++i )
hist[i] = 0;
for ( row = 0; row < rows; ++row )
for ( col = 0, gP = grays[row]; col < cols; ++col, ++gP )
++hist[*gP];
size = rows * cols;
if ( ! specbvalue )
{ /* Compute bvalue from bpercent. */
cutoff = size * bpercent / 100.0;
count = 0;
for ( bvalue = 0; bvalue <= maxval; ++bvalue )
{
count += hist[bvalue];
if ( count > cutoff )
break;
}
}
if ( ! specwvalue )
{ /* Compute wvalue from wpercent. */
cutoff = size * wpercent / 100.0;
count = 0;
for ( wvalue = maxval; wvalue >= 0; wvalue-- )
{
count += hist[wvalue];
if ( count > cutoff )
break;
}
}
/* Now rescale so that bvalue maps to 0, wvalue maps to maxval. */
pm_message(
"remapping %d..%d to %d..%d", bvalue, wvalue, 0, maxval, 0 );
pgm_writepgminit( stdout, cols, rows, maxval, 0 );
for ( i = 0; i <= bvalue; ++i )
hist[i] = 0;
for ( i = wvalue; i <= maxval; ++i )
hist[i] = maxval;
range = wvalue - bvalue;
for ( i = bvalue + 1, val = maxval; i < wvalue; ++i, val += maxval )
hist[i] = val / range;
for ( row = 0; row < rows; ++row )
{
for ( col = 0, gP = grays[row]; col < cols; ++col, ++gP )
*gP = hist[*gP];
pgm_writepgmrow( stdout, grays[row], cols, maxval, 0 );
}
}
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.