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/* libpnm3.c - pnm utility library part 3
**
** 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 "pnm.h"
#include "ppm.h"
#include "libppm.h"
#include "pgm.h"
#include "libpgm.h"
#include "pbm.h"
#include "libpbm.h"
xel
pnm_backgroundxel( xel** xels, int cols, int rows, xelval maxval, int format )
{
xel bgxel, ul, ur, ll, lr;
/* Guess a good background value. */
ul = xels[0][0];
ur = xels[0][cols-1];
ll = xels[rows-1][0];
lr = xels[rows-1][cols-1];
/* First check for three corners equal. */
if ( PNM_EQUAL( ul, ur ) && PNM_EQUAL( ur, ll ) )
bgxel = ul;
else if ( PNM_EQUAL( ul, ur ) && PNM_EQUAL( ur, lr ) )
bgxel = ul;
else if ( PNM_EQUAL( ul, ll ) && PNM_EQUAL( ll, lr ) )
bgxel = ul;
else if ( PNM_EQUAL( ur, ll ) && PNM_EQUAL( ll, lr ) )
bgxel = ur;
/* Nope, check for two corners equal. */
else if ( PNM_EQUAL( ul, ur ) || PNM_EQUAL( ul, ll ) ||
PNM_EQUAL( ul, lr ) )
bgxel = ul;
else if ( PNM_EQUAL( ur, ll ) || PNM_EQUAL( ur, lr ) )
bgxel = ur;
else if ( PNM_EQUAL( ll, lr ) )
bgxel = ll;
else
{
/* Nope, we have to average the four corners. This breaks the
** rules of pnm, but oh well. Let's try to do it portably. */
switch ( PNM_FORMAT_TYPE(format) )
{
case PPM_TYPE:
PPM_ASSIGN( bgxel,
PPM_GETR(ul) + PPM_GETR(ur) + PPM_GETR(ll) + PPM_GETR(lr) / 4,
PPM_GETG(ul) + PPM_GETG(ur) + PPM_GETG(ll) + PPM_GETG(lr) / 4,
PPM_GETB(ul) + PPM_GETB(ur) + PPM_GETB(ll) + PPM_GETB(lr) / 4 );
break;
case PGM_TYPE:
{
gray gul, gur, gll, glr;
gul = (gray) PNM_GET1( ul );
gur = (gray) PNM_GET1( ur );
gll = (gray) PNM_GET1( ll );
glr = (gray) PNM_GET1( lr );
PNM_ASSIGN1( bgxel, ( ( gul + gur + gll + glr ) / 4 ) );
break;
}
case PBM_TYPE:
pm_error(
"pnm_backgroundxel: four bits no two of which equal each other??" );
default:
pm_error( "Invalid format passed to pnm_backgroundxel()");
}
}
return bgxel;
}
xel
pnm_backgroundxelrow( xel* xelrow, int cols, xelval maxval, int format )
{
xel bgxel, l, r;
/* Guess a good background value. */
l = xelrow[0];
r = xelrow[cols-1];
/* First check for both corners equal. */
if ( PNM_EQUAL( l, r ) )
bgxel = l;
else
{
/* Nope, we have to average the two corners. This breaks the
** rules of pnm, but oh well. Let's try to do it portably. */
switch ( PNM_FORMAT_TYPE(format) )
{
case PPM_TYPE:
PPM_ASSIGN( bgxel, PPM_GETR(l) + PPM_GETR(r) / 2,
PPM_GETG(l) + PPM_GETG(r) / 2, PPM_GETB(l) + PPM_GETB(r) / 2 );
break;
case PGM_TYPE:
{
gray gl, gr;
gl = (gray) PNM_GET1( l );
gr = (gray) PNM_GET1( r );
PNM_ASSIGN1( bgxel, ( ( gl + gr ) / 2 ) );
break;
}
case PBM_TYPE:
{
int col, blacks;
/* One black, one white. Gotta count. */
for ( col = 0, blacks = 0; col < cols; ++col )
{
if ( PNM_GET1( xelrow[col] ) == 0 )
++blacks;
}
if ( blacks >= cols / 2 )
PNM_ASSIGN1( bgxel, 0 );
else
PNM_ASSIGN1( bgxel, maxval );
break;
}
default:
pm_error( "Invalid format passed to pnm_backgroundxelrow()");
}
}
return bgxel;
}
xel
pnm_whitexel( xelval maxval, int format )
{
xel x;
switch ( PNM_FORMAT_TYPE(format) )
{
case PPM_TYPE:
PPM_ASSIGN( x, maxval, maxval, maxval );
break;
case PGM_TYPE:
PNM_ASSIGN1( x, maxval );
break;
case PBM_TYPE:
PNM_ASSIGN1( x, maxval );
break;
default:
pm_error( "Invalid format passed to pnm_whitexel()");
}
return x;
}
xel
pnm_blackxel( xelval maxval, int format )
{
xel x;
switch ( PNM_FORMAT_TYPE(format) )
{
case PPM_TYPE:
PPM_ASSIGN( x, 0, 0, 0 );
break;
case PGM_TYPE:
PNM_ASSIGN1( x, (xelval) 0 );
break;
case PBM_TYPE:
PNM_ASSIGN1( x, (xelval) 0 );
break;
default:
pm_error( "Invalid format passed to pnm_blackxel(): %d", format);
}
return x;
}
void
pnm_invertxel(xel* const xP,
xelval const maxval,
int const format) {
switch (PNM_FORMAT_TYPE(format)) {
case PPM_TYPE:
PPM_ASSIGN(*xP,
maxval - PPM_GETR(*xP),
maxval - PPM_GETG(*xP),
maxval - PPM_GETB(*xP));
break;
case PGM_TYPE:
PNM_ASSIGN1(*xP, maxval - PNM_GET1(*xP));
break;
case PBM_TYPE:
PNM_ASSIGN1(*xP, (PNM_GET1(*xP) == 0) ? maxval : 0);
break;
default:
pm_error("Invalid format passed to pnm_invertxel()");
}
}
void
pnm_promoteformat( xel** xels, int cols, int rows, xelval maxval, int format, xelval newmaxval, int newformat )
{
int row;
for ( row = 0; row < rows; ++row )
pnm_promoteformatrow(
xels[row], cols, maxval, format, newmaxval, newformat );
}
void
pnm_promoteformatrow( xel* xelrow, int cols, xelval maxval, int format, xelval newmaxval, int newformat )
{
register int col;
register xel* xP;
if ( ( PNM_FORMAT_TYPE(format) == PPM_TYPE &&
( PNM_FORMAT_TYPE(newformat) == PGM_TYPE ||
PNM_FORMAT_TYPE(newformat) == PBM_TYPE ) ) ||
( PNM_FORMAT_TYPE(format) == PGM_TYPE &&
PNM_FORMAT_TYPE(newformat) == PBM_TYPE ) )
pm_error( "pnm_promoteformatrow: can't promote downwards!" );
/* Are we promoting to the same type? */
if ( PNM_FORMAT_TYPE(format) == PNM_FORMAT_TYPE(newformat) )
{
if ( PNM_FORMAT_TYPE(format) == PBM_TYPE )
return;
if ( newmaxval < maxval )
pm_error(
"pnm_promoteformatrow: can't decrease maxval - try using pnmdepth" );
if ( newmaxval == maxval )
return;
/* Increase maxval. */
switch ( PNM_FORMAT_TYPE(format) )
{
case PGM_TYPE:
for ( col = 0, xP = xelrow; col < cols; ++col, ++xP )
PNM_ASSIGN1(
*xP, (int) PNM_GET1(*xP) * newmaxval / maxval );
break;
case PPM_TYPE:
for ( col = 0, xP = xelrow; col < cols; ++col, ++xP )
PPM_DEPTH( *xP, *xP, maxval, newmaxval );
break;
default:
pm_error( "Invalid old format passed to pnm_promoteformatrow()" );
}
return;
}
/* We must be promoting to a higher type. */
switch ( PNM_FORMAT_TYPE(format) )
{
case PBM_TYPE:
switch ( PNM_FORMAT_TYPE(newformat) )
{
case PGM_TYPE:
for ( col = 0, xP = xelrow; col < cols; ++col, ++xP )
if ( PNM_GET1(*xP) == 0 )
PNM_ASSIGN1( *xP, 0 );
else
PNM_ASSIGN1( *xP, newmaxval );
break;
case PPM_TYPE:
for ( col = 0, xP = xelrow; col < cols; ++col, ++xP )
if ( PNM_GET1(*xP) == 0 )
PPM_ASSIGN( *xP, 0, 0, 0 );
else
PPM_ASSIGN( *xP, newmaxval, newmaxval, newmaxval );
break;
default:
pm_error( "Invalid new format passed to pnm_promoteformatrow()" );
}
break;
case PGM_TYPE:
switch ( PNM_FORMAT_TYPE(newformat) )
{
case PPM_TYPE:
if ( newmaxval < maxval )
pm_error(
"pnm_promoteformatrow: can't decrease maxval - try using pnmdepth" );
if ( newmaxval == maxval )
{
for ( col = 0, xP = xelrow; col < cols; ++col, ++xP )
PPM_ASSIGN(
*xP, PNM_GET1(*xP), PNM_GET1(*xP), PNM_GET1(*xP) );
}
else
{ /* Increase maxval. */
for ( col = 0, xP = xelrow; col < cols; ++col, ++xP )
PPM_ASSIGN(
*xP, (int) PNM_GET1(*xP) * newmaxval / maxval,
(int) PNM_GET1(*xP) * newmaxval / maxval,
(int) PNM_GET1(*xP) * newmaxval / maxval );
}
break;
default:
pm_error( "Invalid new format passed to pnm_promoteformatrow()" );
}
break;
default:
pm_error( "Invalid old format passed to pnm_promoteformatrow()" );
}
}
pixel
xeltopixel(xel const inputxel) {
pixel outputpixel;
PPM_ASSIGN(outputpixel,
PNM_GET1(inputxel), PNM_GET1(inputxel), PNM_GET1(inputxel));
return outputpixel;
}
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