168 lines
3.6 KiB
C
168 lines
3.6 KiB
C
/* Simple rectangle algebra. Should build rectangle list algebra on top of
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* this.
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*
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* J. Cupitt, 8/4/93.
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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 <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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/* Move the margins of a rect. +1 means out one pixel.
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*/
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void
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im_rect_marginadjust( Rect *r, int n )
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{
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r->left -= n;
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r->top -= n;
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r->width += 2 * n;
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r->height += 2 * n;
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}
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/* Does rect contain a point?
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*/
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int
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im_rect_includespoint( Rect *r, int x, int y )
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{
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return( r->left <= x &&
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r->top <= y &&
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r->left + r->width > x &&
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r->top + r->height > y );
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}
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/* Is r2 a subset of r1?
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*/
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int
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im_rect_includesrect( Rect *r1, Rect *r2 )
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{
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return( r1->left <= r2->left &&
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r1->top <= r2->top &&
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r1->left + r1->width >= r2->left + r2->width &&
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r1->top + r1->height >= r2->top + r2->height );
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}
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/* Fill r3 with the intersection of r1 and r2. r3 can equal r1 or r2.
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*/
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void
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im_rect_intersectrect( Rect *r1, Rect *r2, Rect *r3 )
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{
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int left = IM_MAX( r1->left, r2->left );
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int top = IM_MAX( r1->top, r2->top );
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int right = IM_MIN( IM_RECT_RIGHT( r1 ), IM_RECT_RIGHT( r2 ) );
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int bottom = IM_MIN( IM_RECT_BOTTOM( r1 ), IM_RECT_BOTTOM( r2 ) );
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int width = IM_MAX( 0, right - left );
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int height = IM_MAX( 0, bottom - top );
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r3->left = left;
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r3->top = top;
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r3->width = width;
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r3->height = height;
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}
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/* Is a rect empty? ie. zero width or height.
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*/
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int
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im_rect_isempty( Rect *r )
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{
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return( r->width <= 0 || r->height <= 0 );
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}
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/* Fill r3 with the set union of r1 and r2. Can't do this very well, as can
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* only have rectangular areas. Just set to smallest box that encloses both r1
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* and r2. If either is empty, can just return the other.
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*/
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void
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im_rect_unionrect( Rect *r1, Rect *r2, Rect *r3 )
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{
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if( im_rect_isempty( r1 ) )
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*r3 = *r2;
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else if( im_rect_isempty( r2 ) )
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*r3 = *r1;
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else {
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int left = IM_MIN( r1->left, r2->left );
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int top = IM_MIN( r1->top, r2->top );
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int width = IM_MAX( IM_RECT_RIGHT( r1 ),
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IM_RECT_RIGHT( r2 ) ) - left;
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int height = IM_MAX( IM_RECT_BOTTOM( r1 ),
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IM_RECT_BOTTOM( r2 ) )- top;
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r3->left = left;
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r3->top = top;
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r3->width = width;
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r3->height = height;
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}
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}
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/* Test for equality.
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*/
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int
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im_rect_equalsrect( Rect *r1, Rect *r2 )
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{
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return( r1->left == r2->left && r1->top == r2->top &&
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r1->width == r2->width && r1->height == r2->height );
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}
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/* DUP a rect.
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*/
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Rect *
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im_rect_dup( Rect *r )
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{
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Rect *out = IM_NEW( NULL, Rect );
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if( !out )
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return( NULL );
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*out = *r;
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return( out );
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}
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/* Make sure width and height are >0.
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*/
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void
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im_rect_normalise( Rect *r )
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{
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if( r->width < 0 ) {
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r->left += r->width;
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r->width *= -1;
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}
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if( r->height < 0 ) {
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r->top += r->height;
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r->height *= -1;
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}
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}
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