1 files changed, 110 insertions, 0 deletions
diff --git a/pcl/pggeom.c b/pcl/pggeom.c
new file mode 100644
index 000000000..e804388bb
--- /dev/null
+++ b/pcl/pggeom.c
@@ -0,0 +1,110 @@
+/* Portions Copyright (C) 2001 artofcode LLC.
+   Portions Copyright (C) 1996, 2001 Artifex Software Inc.
+   Portions Copyright (C) 1988, 2000 Aladdin Enterprises.
+   This software is based in part on the work of the Independent JPEG Group.
+   All Rights Reserved.
+
+   This software is distributed under license and may not be copied, modified
+   or distributed except as expressly authorized under the terms of that
+   license.  Refer to licensing information at http://www.artifex.com/ or
+   contact Artifex Software, Inc., 101 Lucas Valley Road #110,
+   San Rafael, CA  94903, (415)492-9861, for further information. */
+/*$Id$ */
+
+/* pggeom.c */
+/* HP-GL/2 geometry routines */
+
+#include "stdio_.h"
+#include "pggeom.h"
+#include "gxfarith.h" /* for gs_sincos */
+
+/* HAS most of these computations require more error checking */
+
+/* ------ Lines, angles, arcs, and chords ------ */
+
+/* compute the angle between 0 and 2*PI given the slope */
+floatp
+hpgl_compute_angle(floatp dx, floatp dy)
+{
+	floatp alpha = atan2(dy, dx);
+
+	return (alpha < 0 ? alpha + M_PI * 2.0 : alpha);
+}
+
+/* compute the center of an arc given 3 points on the arc */
+int
+hpgl_compute_arc_center(floatp x1, floatp y1, floatp x2, floatp y2,
+			floatp x3, floatp y3, floatp *pcx, floatp *pcy)
+
+{
+	floatp px2, py2, dx2, dy2, px3, py3, dx3, dy3;
+	double denom, t2;
+
+	/*
+	 * The center is the intersection of the perpendicular bisectors
+	 * of the 3 chords.  Any two will do for the computation.
+	 * (For greatest numerical stability, we should probably choose
+	 * the two outside chords, but this is a refinement that we will
+	 * leave for the future.)
+	 * We define each bisector by a line with the equations
+	 *	xi = pxi + ti * dxi
+	 *	yi = pyi + ti * dyi
+	 * where i is 2 or 3.
+	 */
+
+#define compute_bisector(px, py, dx, dy, xa, ya, xb, yb)\
+  (px = (xa + xb) / 2, py = (ya + yb) / 2,\
+   dx = (ya - yb), dy = (xb - xa) /* 90 degree rotation (either way is OK) */)
+
+	compute_bisector(px2, py2, dx2, dy2, x1, y1, x2, y2);
+	compute_bisector(px3, py3, dx3, dy3, x1, y1, x3, y3);
+
+#undef compute_bisector
+
+	/*
+	 * Now find the intersections by solving for t2 or t3:
+	 *	px2 + t2 * dx2 = px3 + t3 * dx3
+	 *	py2 + t2 * dy2 = py3 + t3 * dy3
+	 * i.e., in standard form,
+	 *	t2 * dx2 - t3 * dx3 = px3 - px2
+	 *	t2 * dy2 - t3 * dy3 = py3 - py2
+	 * The solution of
+	 *	a*x + b*y = c
+	 *	d*x + e*y = f
+	 * is
+	 *	denom = a*e - b*d
+	 *	x = (c*e - b*f) / denom
+	 *	y = (a*f - c*d) / denom
+	 */
+	denom = dx3 * dy2 - dx2 * dy3;
+	if ( fabs(denom) < 1.0e-6 )
+	  return -1;		/* degenerate */
+
+	t2 = ((px3 - px2) * (-dy3) - (-dx3) * (py3 - py2)) / denom;
+	*pcx = px2 + t2 * dx2;
+	*pcy = py2 + t2 * dy2;
+	return 0;
+}
+
+/* compute the coordinates of a point on an arc */
+int
+hpgl_compute_arc_coords(floatp radius, floatp center_x, floatp center_y,
+			floatp angle, floatp *px, floatp *py)
+{
+	gs_sincos_t sincos;
+	gs_sincos_degrees(angle, &sincos);
+	*px = radius * sincos.cos + center_x;
+	*py = radius * sincos.sin + center_y;
+	return 0;
+}
+
+/* given a start point, angle (degrees) and magnitude of a vector compute its
+   endpoints */
+int
+hpgl_compute_vector_endpoints(floatp magnitude, floatp x, floatp y,
+			      floatp angle_degrees, floatp *endx, floatp *endy)
+
+{
+	return hpgl_compute_arc_coords(magnitude, x, y,
+				       angle_degrees, endx, endy);
+}