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/* @#) line drawer. adapted to draw for graphics system
* @(#) Modified to be compatible with the vasari library
* @(#) In order to use this function, the input file should have been set by
* @(#) im_mmapinrw()
*
* Copyright: N. Dessipris
* Written: 02/01/1990
* Modified :
* 22/7/93 JC
* - im_incheck() added
* - externs removed
* 16/8/94 JC
* - im_incheck() changed to im_makerw()
* 5/12/06
* - im_invalidate() after paint
*/
/*
This file is part of VIPS.
VIPS is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301 USA
*/
/*
These files are distributed with VIPS - http://www.vips.ecs.soton.ac.uk
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif /*HAVE_CONFIG_H*/
#include <glib/gi18n-lib.h>
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <vips/vips.h>
int
im_line(IMAGE *image, int x1, int y1, int x2, int y2, int pelval)
{
double x, y, dx, dy, m;
long offset;
double signx, signy;
if (im_rwcheck(image))
return -1;
/* check coordinates */
if ((x1 > image->Xsize) || (x1 < 0) ||
(y1 > image->Ysize) || (y1 < 0) ||
(x2 > image->Xsize) || (x2 < 0) ||
(y2 > image->Ysize) || (y2 < 0)) {
im_error("im_line", "%s", _("invalid line cooordinates"));
return -1;
}
if ((pelval > 255) || (pelval < 0)) {
im_error("im_line", "%s", _("line intensity between 0 and 255"));
return -1;
}
if (image->Bands != 1) {
im_error("im_line", "%s", _("image should have one band only"));
return -1;
}
dx = (double) (x2 - x1);
dy = (double) (y2 - y1);
if (dx < 0.0)
signx = -1.0;
else
signx = 1.0;
if (dy < 0.0)
signy = -1.0;
else
signy = 1.0;
if (dx == 0.0) {
x = x1;
y = y1;
while (y != y2) {
offset = (int) (x + .5) + ((int) (y + .5)) * image->Xsize;
*(image->data + offset) = (PEL) pelval;
y += signy;
}
/* Draw point (x2, y2) */
offset = x2 + y2 * image->Xsize;
*(image->data + offset) = (PEL) pelval;
return 0;
}
if (dy == 0.0) {
y = y1;
x = x1;
while (x != x2) {
offset = (int) (x + .5) + ((int) (y + .5)) * image->Xsize;
*(image->data + offset) = (PEL) pelval;
x += signx;
}
/* Draw point (x2, y2) */
offset = x2 + y2 * image->Xsize;
*(image->data + offset) = (PEL) pelval;
return 0;
}
if (fabs(dy) < fabs(dx)) {
m = fabs(dy / dx) * signy;
y = y1;
x = x1;
while (x != x2) {
offset = (int) (x + .5) + ((int) (y + .5)) * image->Xsize;
*(image->data + offset) = (PEL) pelval;
x += signx;
y += m;
}
}
else {
m = fabs(dx / dy) * signx;
x = x1;
y = y1;
while (y != y2) {
offset = (int) (x + .5) + ((int) (y + .5)) * image->Xsize;
*(image->data + offset) = (PEL) pelval;
x += m;
y += signy;
}
}
/* Draw point (x2, y2) */
offset = x2 + y2 * image->Xsize;
*(image->data + offset) = (PEL) pelval;
im_invalidate(image);
return 0;
}
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