154 lines
3.4 KiB
C
154 lines
3.4 KiB
C
/* @#) line drawer. adapted to draw for graphics system
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* @(#) Modified to be compatible with the vasari library
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* @(#) In order to use this function, the input file should have been set by
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* @(#) im_mmapinrw()
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*
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* Copyright: N. Dessipris
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* Written: 02/01/1990
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* Modified :
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* 22/7/93 JC
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* - im_incheck() added
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* - externs removed
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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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*/
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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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int im_line(image, x1, y1, x2, y2, pelval)
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IMAGE *image;
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int x1, x2, y1, y2, pelval;
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{
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double x, y, dx, dy, m;
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long offset;
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double signx, signy;
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if( im_rwcheck( image ) )
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return( -1 );
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/* check coordinates */
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if ( (x1 > image->Xsize)||(x1<0)||(y1 > image->Ysize)||(y1<0)
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||(x2 > image->Xsize)||(x2<0)||(y2 > image->Ysize)||(y2<0) )
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{ im_errormsg("im_line: invalid line cooordinates"); return(-1); }
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if ((pelval > 255)||(pelval < 0))
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{im_errormsg("im_line: line intensity between 0 and 255"); return(-1); }
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if (image->Bands != 1)
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{ im_errormsg("im_line: image should have one band only");return(-1); }
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dx = (double)(x2 - x1);
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dy = (double)(y2 - y1);
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if (dx < 0.0)
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signx = -1.0;
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else
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signx = 1.0;
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if (dy < 0.0)
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signy = -1.0;
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else
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signy = 1.0;
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if (dx == 0.0)
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{
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x = x1; y = y1;
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while (y != y2)
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{
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offset = (int)(x+.5) + ((int)(y +.5)) * image->Xsize;
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*(image->data + offset) = (PEL)pelval;
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y += signy;
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}
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/* Draw point (x2, y2) */
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offset = x2 + y2 * image->Xsize;
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*(image->data + offset) = (PEL)pelval;
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return(0);
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}
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if (dy == 0.0)
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{
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y = y1; x = x1;
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while (x != x2)
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{
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offset = (int)(x+.5) + ((int)(y +.5)) * image->Xsize;
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*(image->data + offset) = (PEL)pelval;
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x += signx;
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}
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/* Draw point (x2, y2) */
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offset = x2 + y2 * image->Xsize;
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*(image->data + offset) = (PEL)pelval;
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return(0);
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}
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if (fabs(dy) < fabs(dx))
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{
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m = fabs(dy/dx)*signy;
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y = y1;
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x = x1;
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while (x != x2)
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{
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offset = (int)(x+.5) + ((int)(y +.5)) * image->Xsize;
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*(image->data + offset) = (PEL)pelval;
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x += signx;
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y += m;
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}
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}
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else
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{
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m = fabs(dx/dy)*signx;
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x = x1; y = y1;
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while (y != y2)
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{
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offset = (int)(x+.5) + ((int)(y +.5)) * image->Xsize;
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*(image->data + offset) = (PEL)pelval;
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x += m;
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y += signy;
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}
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}
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/* Draw point (x2, y2) */
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offset = x2 + y2 * image->Xsize;
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*(image->data + offset) = (PEL)pelval;
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im_invalidate( image );
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return(0);
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}
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