314 lines
7.4 KiB
C
314 lines
7.4 KiB
C
/* @(#) Shrink any non-complex image by some x, y, factor. No interpolation!
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* @(#) Just average an area. Suitable for making quicklooks only!
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* @(#)
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* @(#) int
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* @(#) im_shrink( in, out, xshrink, yshrink )
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* @(#) IMAGE *in, *out;
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* @(#) double xshrink, yshrink;
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* @(#)
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* @(#) Returns either 0 (success) or -1 (fail)
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* @(#)
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*
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* Copyright: 1990, N. Dessipris.
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*
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* Authors: Nicos Dessipris and Kirk Martinez
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* Written on: 29/04/1991
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* Modified on: 2/11/92, 22/2/93 Kirk Martinez - Xres Yres & cleanup
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incredibly inefficient for box filters as LUTs are used instead of +
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Needs converting to a smoother filter: eg Gaussian! KM
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* 15/7/93 JC
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* - rewritten for partial v2
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* - ANSIfied
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* - now shrinks any non-complex type
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* - no longer cloned from im_convsub()
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* - could be much better! see km comments above
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* 3/8/93 JC
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* - rounding bug fixed
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* 11/1/94 JC
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* - problems with .000001 and round up/down ignored! Try shrink 3738
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* pixel image by 9.345000000001
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* 7/10/94 JC
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* - IM_NEW and IM_ARRAY added
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* - more typedef
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* 3/7/95 JC
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* - IM_CODING_LABQ handling added here
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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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/* Our main parameter struct.
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*/
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typedef struct {
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double xshrink; /* Shrink factors */
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double yshrink;
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int mw; /* Size of area we average */
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int mh;
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int np; /* Number of pels we average */
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} ShrinkInfo;
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/* Our per-sequence parameter struct. We hold an offset for each pel we
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* average.
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*/
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typedef struct {
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REGION *ir;
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int *off;
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} SeqInfo;
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/* Free a sequence value.
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*/
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static int
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shrink_stop( SeqInfo *seq, IMAGE *in, ShrinkInfo *st )
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{
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if( seq->ir ) {
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im_region_free( seq->ir );
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seq->ir = NULL;
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}
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return( 0 );
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}
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/* Make a sequence value.
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*/
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static void *
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shrink_start( IMAGE *out, IMAGE *in, ShrinkInfo *st )
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{
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SeqInfo *seq = IM_NEW( out, SeqInfo );
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if( !seq )
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return( NULL );
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/* Init!
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*/
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seq->ir = NULL;
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seq->off = NULL;
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seq->ir = im_region_create( in );
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seq->off = IM_ARRAY( out, st->np, int );
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if( !seq->off || !seq->ir ) {
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shrink_stop( seq, in, st );
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return( NULL );
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}
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return( (void *) seq );
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}
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/* Integer shrink.
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*/
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#define ishrink(TYPE) \
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for( y = to; y < bo; y++ ) { \
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TYPE *q = (TYPE *) IM_REGION_ADDR( or, le, y ); \
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\
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for( x = le; x < ri; x++ ) { \
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int ix = x * st->xshrink; \
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int iy = y * st->yshrink; \
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TYPE *p = (TYPE *) IM_REGION_ADDR( ir, ix, iy ); \
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\
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for( b = 0; b < ir->im->Bands; b++ ) { \
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int sum = 0; \
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int *t = seq->off; \
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\
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for( z = 0; z < st->np; z++ ) \
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sum += p[*t++]; \
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\
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*q++ = sum / st->np; \
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p++; \
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} \
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} \
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}
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/* FP shrink.
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*/
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#define fshrink(TYPE) \
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for( y = to; y < bo; y++ ) { \
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TYPE *q = (TYPE *) IM_REGION_ADDR( or, le, y ); \
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\
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for( x = le; x < ri; x++ ) { \
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int ix = x * st->xshrink; \
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int iy = y * st->yshrink; \
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TYPE *p = (TYPE *) IM_REGION_ADDR( ir, ix, iy ); \
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\
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for( b = 0; b < ir->im->Bands; b++ ) { \
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double sum = 0; \
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int *t = seq->off; \
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\
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for( z = 0; z < st->np; z++ ) \
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sum += p[*t++]; \
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\
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*q++ = sum / st->np; \
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p++; \
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} \
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} \
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}
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/* Shrink a REGION.
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*/
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static int
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shrink_gen( REGION *or, SeqInfo *seq, IMAGE *in, ShrinkInfo *st )
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{
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REGION *ir = seq->ir;
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Rect *r = &or->valid;
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Rect s;
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int le = r->left;
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int ri = IM_RECT_RIGHT( r );
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int to = r->top;
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int bo = IM_RECT_BOTTOM(r);
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int x, y, z, b;
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/* What part of the input image do we need? Very careful: round left
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* down, round right up.
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*/
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s.left = r->left * st->xshrink;
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s.top = r->top * st->yshrink;
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s.width = ceil( IM_RECT_RIGHT( r ) * st->xshrink ) - s.left;
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s.height = ceil( IM_RECT_BOTTOM( r ) * st->yshrink ) - s.top;
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if( im_prepare( ir, &s ) )
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return( -1 );
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/* Init offsets for pel addressing. Note that offsets must be for the
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* type we will address the memory array with.
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*/
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for( z = 0, y = 0; y < st->mh; y++ )
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for( x = 0; x < st->mw; x++ )
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seq->off[z++] = (IM_REGION_ADDR( ir, x, y ) - IM_REGION_ADDR( ir, 0, 0 )) /
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IM_IMAGE_SIZEOF_ELEMENT( ir->im );
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switch( ir->im->BandFmt ) {
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case IM_BANDFMT_UCHAR: ishrink(unsigned char); break;
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case IM_BANDFMT_CHAR: ishrink(char); break;
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case IM_BANDFMT_USHORT: ishrink(unsigned short); break;
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case IM_BANDFMT_SHORT: ishrink(short); break;
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case IM_BANDFMT_UINT: ishrink(unsigned int); break;
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case IM_BANDFMT_INT: ishrink(int); break;
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case IM_BANDFMT_FLOAT: fshrink(float); break;
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case IM_BANDFMT_DOUBLE: fshrink(double); break;
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default:
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im_errormsg( "im_shrink: unsupported input format" );
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return( -1 );
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}
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return( 0 );
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}
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static int
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shrink( IMAGE *in, IMAGE *out, double xshrink, double yshrink )
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{
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ShrinkInfo *st;
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/* Check parameters.
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*/
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if( !in || im_iscomplex( in ) ) {
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im_errormsg( "im_shrink: non-complex input only" );
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return( -1 );
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}
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if( xshrink < 1.0 || yshrink < 1.0 ) {
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im_errormsg( "im_shrink: shrink factors should both be >1" );
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return( -1 );
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}
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if( im_piocheck( in, out ) )
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return( -1 );
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/* Prepare output. Note: we round the output width down!
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*/
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if( im_cp_desc( out, in ) )
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return( -1 );
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out->Xsize = in->Xsize / xshrink;
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out->Ysize = in->Ysize / yshrink;
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out->Xres = in->Xres / xshrink;
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out->Yres = in->Yres / yshrink;
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if( out->Xsize <= 0 || out->Ysize <= 0 ) {
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im_errormsg( "im_shrink: image has shrunk to nothing" );
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return( -1 );
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}
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/* Build and attach state struct.
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*/
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if( !(st = IM_NEW( out, ShrinkInfo )) )
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return( -1 );
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st->xshrink = xshrink;
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st->yshrink = yshrink;
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st->mw = ceil( xshrink );
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st->mh = ceil( yshrink );
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st->np = st->mw * st->mh;
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/* Set demand hints. We want THINSTRIP, as we will be demanding a
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* large area of input for each output line.
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*/
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if( im_demand_hint( out, IM_THINSTRIP, in, NULL ) )
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return( -1 );
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/* Generate!
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*/
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if( im_generate( out,
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shrink_start, shrink_gen, shrink_stop, in, st ) )
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return( -1 );
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return( 0 );
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}
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/* Wrap up the above: do IM_CODING_LABQ as well.
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*/
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int
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im_shrink( IMAGE *in, IMAGE *out, double xshrink, double yshrink )
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{
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if( in->Coding == IM_CODING_LABQ ) {
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IMAGE *t[2];
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if( im_open_local_array( out, t, 2, "im_shrink:1", "p" ) ||
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im_LabQ2LabS( in, t[0] ) ||
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shrink( t[0], t[1], xshrink, yshrink ) ||
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im_LabS2LabQ( t[1], out ) )
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return( -1 );
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}
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else if( in->Coding == IM_CODING_NONE ) {
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if( shrink( in, out, xshrink, yshrink ) )
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return( -1 );
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}
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else {
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im_errormsg( "im_shrink: unknown coding type" );
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return( -1 );
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}
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return( 0 );
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}
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