137 lines
3.2 KiB
C
137 lines
3.2 KiB
C
/* find percent of pixels
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* Copyright: 1990, N. Dessipris
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*
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* Author: N. Dessipris
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* Written on: 02/08/1990
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* Modified on : 29/4/93 K.Martinez for Sys5
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* 20/2/95 JC
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* - now returns result through parameter
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* - ANSIfied a little
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* 19/1/07
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* - redone with the vips hist operators
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* 25/3/10
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* - gtkdoc
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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 <string.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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/**
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* im_mpercent_hist:
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* @hist: input histogram image
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* @percent: threshold percentage
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* @out: output threshold value
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*
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* Just like im_mpercent(), except it works on an image histogram. Handy if
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* you want to run im_mpercent() several times without having to recompute the
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* histogram each time.
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*
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* See also: im_mpercent().
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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_mpercent_hist( IMAGE *hist, double percent, int *out )
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{
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IMAGE *base;
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IMAGE *t[6];
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double pos;
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if( im_check_hist( "im_mpercent", hist ) )
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return( -1 );
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if( !(base = im_open( "im_mpercent", "p" )) )
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return( -1 );
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if( im_open_local_array( base, t, 6, "im_mpercent", "p" ) ) {
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im_close( base );
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return( -1 );
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}
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if( im_histcum( hist, t[1] ) ||
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im_histnorm( t[1], t[2] ) ||
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im_lessconst( t[2], t[3], percent * t[2]->Xsize ) ||
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im_fliphor( t[3], t[4] ) ||
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im_profile( t[4], t[5], 1 ) ||
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im_avg( t[5], &pos ) ) {
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im_close( base );
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return( -1 );
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}
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im_close( base );
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*out = pos;
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return( 0 );
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}
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/**
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* im_mpercent:
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* @in: input image
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* @percent: threshold percentage
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* @out: output threshold value
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*
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* im_mpercent() returns (through the @out parameter) the threshold above
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* which there are @percent values of @in. If for example percent=.1, the
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* number of pels of the input image with values greater than the returned
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* int will correspond to 10% of all pels of the image.
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*
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* The function works for uchar and ushort images only. It can be used
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* to threshold the scaled result of a filtering operation.
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*
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* See also: im_histgr(), im_profile().
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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_mpercent( IMAGE *in, double percent, int *out )
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{
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IMAGE *t;
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if( !(t = im_open( "im_mpercent1", "p" )) )
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return( -1 );
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if( im_histgr( in, t, -1 ) ||
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im_mpercent_hist( t, percent, out ) ) {
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im_close( t );
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return( -1 );
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}
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im_close( t );
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return( 0 );
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}
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