326 lines
7.1 KiB
C
326 lines
7.1 KiB
C
/* @(#) Function which erodes a binary VASARI format picture with a mask.
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* @(#) The mask coefficients are either 255 (object) or 0 (bk) or 128 (any).
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* @(#) Input image are binary images with either 0 or 255 values, one channel
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* @(#) only. The program erodes a white object on a black background.
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* @(#) The center of the mask is at location (m->xsize/2, m->ysize/2)
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* @(#) integer division. The mask is expected to have an odd width and
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* @(#) height.
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* @(#)
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* @(#) int im_erode(in, out, m)
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* @(#) IMAGE *in, *out;
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* @(#) INTMASK *m;
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* @(#)
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* @(#) Returns either 0 (sucess) or -1 (fail)
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*
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* 19/9/95 JC
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* - rewrite
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* 6/7/99 JC
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* - checks and small tidies
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* 7/4/04
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* - now uses im_embed() with edge stretching on the input, not
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* the output
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* - sets Xoffset / Yoffset
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* 21/4/08
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* - only rebuild the buffer offsets if bpl changes
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* - small cleanups
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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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/*
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#define DEBUG
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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 <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 sequence value.
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*/
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typedef struct {
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REGION *ir; /* Input region */
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int *soff; /* Offsets we check for set */
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int ss; /* ... and number we check for set */
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int *coff; /* Offsets we check for clear */
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int cs; /* ... and number we check for clear */
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int last_bpl; /* Avoid recalcing offsets, if we can */
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} SeqInfo;
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/* Stop function.
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*/
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static int
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erode_stop( void *vseq, void *a, void *b )
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{
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SeqInfo *seq = (SeqInfo *) vseq;
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IM_FREEF( im_region_free, seq->ir );
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return( 0 );
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}
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/* Start function.
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*/
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static void *
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erode_start( IMAGE *out, void *a, void *b )
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{
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IMAGE *in = (IMAGE *) a;
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INTMASK *msk = (INTMASK *) b;
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SeqInfo *seq;
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int sz = msk->xsize * msk->ysize;
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if( !(seq = IM_NEW( out, SeqInfo )) )
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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->soff = NULL;
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seq->ss = 0;
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seq->coff = NULL;
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seq->cs = 0;
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seq->last_bpl = -1;
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/* Attach region and arrays.
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*/
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seq->ir = im_region_create( in );
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seq->soff = IM_ARRAY( out, sz, int );
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seq->coff = IM_ARRAY( out, sz, int );
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if( !seq->ir || !seq->soff || !seq->coff ) {
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erode_stop( seq, in, NULL );
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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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/* Erode!
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*/
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static int
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erode_gen( REGION *or, void *vseq, void *a, void *b )
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{
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SeqInfo *seq = (SeqInfo *) vseq;
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INTMASK *msk = (INTMASK *) b;
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REGION *ir = seq->ir;
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int *soff = seq->soff;
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int *coff = seq->coff;
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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 to = r->top;
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int bo = IM_RECT_BOTTOM(r);
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int sz = IM_REGION_N_ELEMENTS( or );
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int *t;
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int x, y;
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int result, i;
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/* Prepare the section of the input image we need. A little larger
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* than the section of the output image we are producing.
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*/
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s = *r;
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s.width += msk->xsize - 1;
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s.height += msk->ysize - 1;
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if( im_prepare( ir, &s ) )
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return( -1 );
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#ifdef DEBUG
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printf( "erode_gen: preparing %dx%d pixels\n", s.width, s.height );
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#endif /*DEBUG*/
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/* Scan mask, building offsets we check when processing. Only do this
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* if the bpl has changed since the previous im_prepare().
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*/
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if( seq->last_bpl != IM_REGION_LSKIP( ir ) ) {
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seq->last_bpl = IM_REGION_LSKIP( ir );
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seq->ss = 0;
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seq->cs = 0;
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for( t = msk->coeff, y = 0; y < msk->ysize; y++ )
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for( x = 0; x < msk->xsize; x++, t++ )
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switch( *t ) {
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case 255:
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soff[seq->ss++] =
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IM_REGION_ADDR( ir,
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x + le, y + to ) -
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IM_REGION_ADDR( ir, le, to );
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break;
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case 128:
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break;
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case 0:
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coff[seq->cs++] =
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IM_REGION_ADDR( ir,
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x + le, y + to ) -
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IM_REGION_ADDR( ir, le, to );
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break;
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default:
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im_error( "im_erode",
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_( "bad mask element (%d "
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"should be 0, 128 or 255)" ),
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*t );
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return( -1 );
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}
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}
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/* Erode!
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*/
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for( y = to; y < bo; y++ ) {
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PEL *p = (PEL *) IM_REGION_ADDR( ir, le, y );
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PEL *q = (PEL *) IM_REGION_ADDR( or, le, y );
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/* Loop along line.
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*/
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for( x = 0; x < sz; x++, q++, p++ ) {
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/* Check all set pixels are set.
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*/
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result = 255;
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for( i = 0; i < seq->ss; i++ )
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if( !p[soff[i]] ) {
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/* Found a mismatch!
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*/
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result = 0;
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break;
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}
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/* Check all clear pixels are clear.
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*/
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if( result )
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for( i = 0; i < seq->cs; i++ )
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if( p[coff[i]] ) {
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result = 0;
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break;
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}
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*q = result;
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}
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}
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return( 0 );
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}
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/* Erode an image.
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*/
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int
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im_erode_raw( IMAGE *in, IMAGE *out, INTMASK *m )
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{
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INTMASK *msk;
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/* Check mask has odd number of elements in width and height.
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*/
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if( m->xsize < 1 || !(m->xsize & 0x1) ||
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m->ysize < 1 || !(m->ysize & 0x1) ) {
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im_error( "im_erode", _( "mask size not odd" ) );
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return( -1 );
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}
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/* Standard checks.
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*/
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if( im_piocheck( in, out ) )
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return( -1 );
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if( in->Coding != IM_CODING_NONE || in->Bbits != 8 ||
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in->BandFmt != IM_BANDFMT_UCHAR ) {
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im_error( "im_erode", _( "1-band uchar uncoded only" ) );
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return( -1 );
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}
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if( im_cp_desc( out, in ) )
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return( -1 );
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/* Prepare output. Consider a 7x7 mask and a 7x7 image --- the output
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* would be 1x1.
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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 -= m->xsize - 1;
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out->Ysize -= m->ysize - 1;
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if( out->Xsize <= 0 || out->Ysize <= 0 ) {
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im_error( "im_erode", _( "image too small for mask" ) );
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return( -1 );
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}
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/* Take a copy of m.
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*/
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if( !(msk = im_dup_imask( m, "conv_mask" )) )
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return( -1 );
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if( im_add_close_callback( out,
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(im_callback_fn) im_free_imask, msk, NULL ) ) {
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im_free_imask( msk );
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return( -1 );
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}
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/* Set demand hints. FATSTRIP is good for us, as THINSTRIP will cause
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* too many recalculations on overlaps.
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*/
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if( im_demand_hint( out, IM_FATSTRIP, 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, erode_start, erode_gen, erode_stop, in, msk ) )
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return( -1 );
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out->Xoffset = -m->xsize / 2;
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out->Yoffset = -m->ysize / 2;
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return( 0 );
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}
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/* The above, with a border to make out the same size as in.
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*/
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int
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im_erode( IMAGE *in, IMAGE *out, INTMASK *m )
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{
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IMAGE *t1 = im_open_local( out, "im_erode:1", "p" );
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if( !t1 ||
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im_embed( in, t1, 1, m->xsize / 2, m->ysize / 2,
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in->Xsize + m->xsize - 1,
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in->Ysize + m->ysize - 1 ) ||
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im_erode_raw( t1, out, m ) )
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return( -1 );
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out->Xoffset = 0;
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out->Yoffset = 0;
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return( 0 );
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}
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