220 lines
5.1 KiB
C
220 lines
5.1 KiB
C
/* draw a circle on an image
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*
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* Author N. Dessipris
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* Written on 30/05/1990
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* Updated on:
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* 22/7/93 JC
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* - im_incheck() call added
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* 16/8/94 JC
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* - im_incheck() changed to im_makerw()
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* 5/12/06
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* - im_invalidate() after paint
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* 6/3/10
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* - don't im_invalidate() after paint, this now needs to be at a higher
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* level
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* 18/8/10
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* - gtkdoc
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* - rewritten: clips, fills, any bands, any format
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* 27/9/10
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* - break base out to Draw
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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 <string.h>
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#include <vips/vips.h>
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#include "draw.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 state.
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*/
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typedef struct {
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Draw draw;
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/* Parameters.
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*/
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int cx, cy;
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int radius;
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gboolean fill;
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/* Derived stuff.
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*/
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PEL *centre;
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} Circle;
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static void
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circle_octants( Circle *circle, int x, int y )
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{
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Draw *draw = DRAW( circle );
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if( circle->fill ) {
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const int cx = circle->cx;
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const int cy = circle->cy;
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im__draw_scanline( draw, cy + y, cx - x, cx + x );
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im__draw_scanline( draw, cy - y, cx - x, cx + x );
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im__draw_scanline( draw, cy + x, cx - y, cx + y );
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im__draw_scanline( draw, cy - x, cx - y, cx + y );
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}
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else if( DRAW( circle )->noclip ) {
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const size_t lsize = draw->lsize;
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const size_t psize = draw->psize;
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PEL *centre = circle->centre;
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im__draw_pel( draw, centre + lsize * y - psize * x );
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im__draw_pel( draw, centre + lsize * y + psize * x );
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im__draw_pel( draw, centre - lsize * y - psize * x );
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im__draw_pel( draw, centre - lsize * y + psize * x );
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im__draw_pel( draw, centre + lsize * x - psize * y );
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im__draw_pel( draw, centre + lsize * x + psize * y );
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im__draw_pel( draw, centre - lsize * x - psize * y );
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im__draw_pel( draw, centre - lsize * x + psize * y );
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}
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else {
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const int cx = circle->cx;
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const int cy = circle->cy;
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im__draw_pel_clip( draw, cx + y, cy - x );
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im__draw_pel_clip( draw, cx + y, cy + x );
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im__draw_pel_clip( draw, cx - y, cy - x );
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im__draw_pel_clip( draw, cx - y, cy + x );
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im__draw_pel_clip( draw, cx + x, cy - y );
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im__draw_pel_clip( draw, cx + x, cy + y );
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im__draw_pel_clip( draw, cx - x, cy - y );
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im__draw_pel_clip( draw, cx - x, cy + y );
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}
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}
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static void
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circle_free( Circle *circle )
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{
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im__draw_free( DRAW( circle ) );
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im_free( circle );
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}
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static Circle *
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circle_new( IMAGE *im, int cx, int cy, int radius, gboolean fill, PEL *ink )
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{
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Circle *circle;
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if( !(circle = IM_NEW( NULL, Circle )) )
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return( NULL );
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if( !im__draw_init( DRAW( circle ), im, ink ) ) {
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circle_free( circle );
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return( NULL );
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}
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circle->cx = cx;
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circle->cy = cy;
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circle->radius = radius;
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circle->fill = fill;
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circle->centre = (PEL *) IM_IMAGE_ADDR( im, cx, cy );
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if( cx - radius >= 0 && cx + radius < im->Xsize &&
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cy - radius >= 0 && cy + radius < im->Ysize )
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DRAW( circle )->noclip = TRUE;
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return( circle );
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}
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static void
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circle_draw( Circle *circle )
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{
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int x, y, d;
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y = circle->radius;
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d = 3 - 2 * circle->radius;
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for( x = 0; x < y; x++ ) {
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circle_octants( circle, x, y );
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if( d < 0 )
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d += 4 * x + 6;
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else {
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d += 4 * (x - y) + 10;
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y--;
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}
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}
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if( x == y )
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circle_octants( circle, x, y );
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}
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/**
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* im_draw_circle:
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* @image: image to draw on
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* @cx: centre of circle
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* @cy: centre of circle
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* @radius: circle radius
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* @fill: fill the circle
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* @ink: value to draw
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*
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* Draws a circle on @image. If @fill is %TRUE then the circle is filled,
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* otherwise a 1-pixel-wide perimeter is drawn.
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*
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* @ink is an array of bytes containing a valid pixel for the image's format.
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* It must have at least IM_IMAGE_SIZEOF_PEL( @image ) bytes.
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*
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* This an inplace operation, so @image is changed. It does not thread and will
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* not work well as part of a pipeline. On 32-bit machines it will be limited
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* to 2GB images.
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*
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* See also: im_draw_line().
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*
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* Returns: 0 on success, or -1 on error.
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*/
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int
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im_draw_circle( VipsImage *image,
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int cx, int cy, int radius, gboolean fill, PEL *ink )
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{
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if( cx + radius >= 0 && cx - radius < image->Xsize &&
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cy + radius >= 0 && cy - radius < image->Ysize ) {
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Circle *circle;
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if( im_check_coding_known( "im_draw_circle", image ) ||
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!(circle = circle_new( image,
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cx, cy, radius, fill, ink )) )
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return( -1 );
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circle_draw( circle );
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circle_free( circle );
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}
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return( 0 );
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}
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