157 lines
3.4 KiB
C
157 lines
3.4 KiB
C
/* grey ramps
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*
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* Copyright: 1990, N. Dessipris.
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*
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* Author: Nicos Dessipris
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* Written on: 02/02/1990
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* Modified on:
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* 22/7/93 JC
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* - im_outcheck() added
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* - externs removed
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* 8/2/95 JC
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* - ANSIfied
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* - im_fgrey() made from im_grey()
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* 31/8/95 JC
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* - now makes [0,1], rather than [0,256)
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* - im_grey() now defined in terms of im_fgrey()
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* 2/3/98 JC
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* - partialed
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* 1/2/11
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* - gtk-doc
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*/
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/*
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This file is part of VIPS.
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VIPS is free software; you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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/*
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These files are distributed with VIPS - http://www.vips.ecs.soton.ac.uk
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*/
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#ifdef HAVE_CONFIG_H
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#include <config.h>
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#endif /*HAVE_CONFIG_H*/
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#include <vips/intl.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <math.h>
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#include <vips/vips.h>
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#ifdef WITH_DMALLOC
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#include <dmalloc.h>
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#endif /*WITH_DMALLOC*/
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/* Generate function.
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*/
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static int
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fgrey_gen( REGION *or, void *seq, void *a, void *b )
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{
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Rect *r = &or->valid;
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int le = r->left;
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int to = r->top;
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int iwm = or->im->Xsize - 1;
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int x, y;
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for( y = 0; y < r->height; y++ ) {
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float *q = (float *) IM_REGION_ADDR( or, le, y + to );
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for( x = 0; x < r->width; x++ )
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q[x] = (float) (x + le) / iwm;
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}
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return( 0 );
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}
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/**
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* im_fgrey:
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* @out: output image
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* @xsize: image size
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* @ysize: image size
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*
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* Create a one-band float image with the left-most column zero and the
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* right-most 1. Intermediate pixels are a linear ramp.
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*
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* See also: im_grey(), im_make_xy(), im_identity().
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*
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* Returns: 0 on success, -1 on error
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*/
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int
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im_fgrey( IMAGE *out, const int xsize, const int ysize )
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{
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/* Check args.
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*/
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if( xsize <=0 || ysize <= 0 ) {
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im_error( "im_fgrey", "%s", _( "bad size" ) );
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return( -1 );
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}
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if( im_poutcheck( out ) )
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return( -1 );
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/* Set image.
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*/
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im_initdesc( out, xsize, ysize, 1, IM_BBITS_FLOAT, IM_BANDFMT_FLOAT,
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IM_CODING_NONE, IM_TYPE_B_W, 1.0, 1.0, 0, 0 );
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/* Set hints - ANY is ok with us.
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*/
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if( im_demand_hint( out, IM_ANY, NULL ) )
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return( -1 );
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/* Generate image.
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*/
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if( im_generate( out, NULL, fgrey_gen, NULL, NULL, NULL ) )
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return( -1 );
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return( 0 );
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}
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/**
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* im_grey:
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* @out: output image
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* @xsize: image size
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* @ysize: image size
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*
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* Create a one-band uchar image with the left-most column zero and the
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* right-most 255. Intermediate pixels are a linear ramp.
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*
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* See also: im_fgrey(), im_make_xy(), im_identity().
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*
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* Returns: 0 on success, -1 on error
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*/
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int
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im_grey( IMAGE *out, const int xsize, const int ysize )
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{
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IMAGE *t[2];
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/* Change range to [0,255].
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*/
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if( im_open_local_array( out, t, 2, "im_grey", "p" ) ||
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im_fgrey( t[0], xsize, ysize ) ||
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im_lintra( 255.0, t[0], 0.0, t[1] ) ||
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im_clip2fmt( t[1], out, IM_BANDFMT_UCHAR ) )
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return( -1 );
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return( 0 );
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}
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