X-Git-Url: http://git.kpe.io/?a=blobdiff_plain;f=libctgraphics%2Fcircle.cpp;fp=libctgraphics%2Fcircle.cpp;h=373edae463bacb178d98ec8cb9739655c9b5238a;hb=bf7295a63667dcca309389ee6dd5328a3a25f22b;hp=0000000000000000000000000000000000000000;hpb=1eb1fcf291b39a016864d78a4060e83cd9046437;p=ctsim.git

diff --git a/libctgraphics/circle.cpp b/libctgraphics/circle.cpp
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+++ b/libctgraphics/circle.cpp
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+/*****************************************************************************
+**  This is part of the CTSim program
+**  Copyright (C) 1983-2000 Kevin Rosenberg
+**
+**  $Id: circle.cpp,v 1.1 2000/06/19 18:05:03 kevin Exp $
+**  $Log: circle.cpp,v $
+**  Revision 1.1  2000/06/19 18:05:03  kevin
+**  initial cvs import
+**
+**  Revision 1.1  2000/06/13 16:20:31  kevin
+**  finished c++ conversions
+**
+**  Revision 1.2  2000/05/24 22:49:01  kevin
+**  Updated SGP: first function X-windows version
+**
+**  Revision 1.1.1.1  2000/04/28 13:02:44  kevin
+**  Initial CVS import for first public release
+**
+**
+**
+**  This program is free software; you can redistribute it and/or modify
+**  it under the terms of the GNU General Public License (version 2) as
+**  published by the Free Software Foundation.
+**
+**  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 General Public License for more details.
+**
+**  You should have received a copy of the GNU General Public License
+**  along with this program; if not, write to the Free Software
+**  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+******************************************************************************/
+
+/* FUNCTION
+ * sgp2_circle - draw circle of radius r at current center		
+ */
+
+#include "math.h"
+#include "kmath.h"
+#include "sgp.h"
+
+void 
+sgp2_draw_circle (const double r)
+{
+	sgp2_draw_arc (0.0, 7.0, r);
+}
+
+/*==============================================================*/
+/* draw arc around current center.  pass angles and radius	*/
+/*==============================================================*/
+
+void 
+sgp2_draw_arc (double start, double stop, const double r)
+{
+	double c, s, theta, angle;
+	float x, y, xp, yp;
+
+	if ((stop-start) > 2 * PI)
+	    stop = start + 2 * PI;
+	if ((start-stop) > 2 * PI)
+	    stop = start + 2 * PI;
+	while (start >= stop)
+	    stop += 2*PI;
+
+	x = r * cos ((double) start);
+	y = r * sin ((double) start);
+	sgp2_move_rel (x, y);          /* move from center to start of arc */
+
+	theta = 5 * PI / 180;
+	c = cos(theta);
+	s = sin(theta);
+
+	for (angle = start; angle < stop - theta; angle += theta) {
+	    xp = c * x - s * y;
+	    yp = s * x + c * y;
+	    sgp2_line_rel (xp - x, yp - y);
+	    x = xp; y = yp;
+	}
+
+	c = cos (stop - angle);
+	s = sin (stop - angle);
+	xp = c * x - s * y;
+	yp = s * x + c * y;
+	sgp2_line_rel (xp - x, yp - y);
+
+	x = r * cos ((double) stop);
+	y = r * sin ((double) stop);
+	sgp2_move_rel (-x, -y);		/* move back to center of circle */
+}