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[ctsim.git] / libctsupport / xform.cpp

diff --git a/libctsupport/xform.cpp b/libctsupport/xform.cpp
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+/*****************************************************************************
+**  This is part of the CTSim program
+**  Copyright (C) 1983-2000 Kevin Rosenberg
+**
+**  $Id: xform.cpp,v 1.1 2000/06/19 02:58:08 kevin Exp $
+**
+**  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
+******************************************************************************/
+
+#include "kmath.h"
+
+/* NAME
+ *   rotate2d          Rotates an array of 2 dimensional vectors
+ *
+ * SYNOPSIS
+ *   rotate2d (x, y, n, angle)
+ *   double x[], y[]   Array of points
+ *   int n             Number of points in array
+ *   double angle      Rotation angle (counter-clockwise)
+ */
+
+void 
+rotate2d (double x[], double y[], int n, double angle)
+{
+  double cos_theta = cos (angle);
+  double sin_theta = sin (angle);
+
+  for (int i = 0; i < n; i++) {
+    double xrot = x[i] * cos_theta - y[i] * sin_theta;
+    double yrot = x[i] * sin_theta + y[i] * cos_theta;
+    x[i] = xrot;
+    y[i] = yrot;
+  }
+}
+
+
+/* NAME
+ *   xlat2d                    Translates an array of 2 dimensional vectors
+ *
+ * SYNOPSIS
+ *   xlat2d (x, y, n, xoffset, yoffset)
+ *   double x[], y[]           Array of points
+ *   int n                     Number of points in array
+ *   double xoffset, yoffset   Offset to translate points by
+ */
+
+void 
+xlat2d (double x[], double y[], int n, double xoffset, double yoffset)
+{
+  for (int i = 0; i < n; i++) {
+    x[i] += xoffset;
+    y[i] += yoffset;
+  }
+}
+
+
+/* NAME
+ *   scale2d                   Scale an array of 2 dimensional vectors
+ *
+ * SYNOPSIS
+ *   scale2d (x, y, n, xoffset, yoffset)
+ *   double x[], y[]           Array of points
+ *   int n                     Number of points in array
+ *   double xfact, yfact       x & y scaling factors
+ */
+
+void 
+scale2d (double x[], double y[], int n, double xfact, double yfact)
+{
+  for (int i = 0; i < n; i++) {
+    x[i] *= xfact;
+    y[i] *= yfact;
+  }
+}
+
+
+void 
+indent_mtx2 (GRFMTX_2D m)
+{
+  m[0][0] = 1.0;  m[0][1] = 0.0;  m[0][2] = 0.0;
+  m[1][0] = 0.0;  m[1][1] = 1.0;  m[1][2] = 0.0;
+  m[2][0] = 0.0;  m[2][1] = 0.0;  m[2][2] = 1.0;
+}
+
+void 
+xlat_mtx2 (GRFMTX_2D m, const double x, const double y)
+{
+  indent_mtx2 (m);
+  m[2][0] = x;
+  m[2][1] = y;
+}
+
+void 
+scale_mtx2 (GRFMTX_2D m, const double sx, const double sy)
+{
+  indent_mtx2 (m);
+  m[0][0] = sx;
+  m[1][1] = sy;
+}
+
+void 
+rot_mtx2 (GRFMTX_2D m, const double theta)
+{
+  double c = cos(theta);
+  double s = sin(theta);
+
+  indent_mtx2 (m);
+  m[0][0] =  c;  m[0][1] = s;
+  m[1][0] = -s;  m[1][1] = c;
+}
+
+void 
+mult_mtx2 (GRFMTX_2D m1, GRFMTX_2D m2, GRFMTX_2D result)
+{
+  GRFMTX_2D temp;
+
+  for (int row = 0; row < 3; row++)
+    for (int col = 0; col < 3; col++) {
+      temp[row][col] = 0;
+      for (int calc = 0; calc < 3; calc++)
+       temp[row][col] += m1[row][calc] * m2[calc][col];
+    }
+
+  for (int row = 0; row < 3; row++)
+    for (int col = 0; col < 3; col++)
+      result[row][col] = temp[row][col];
+}
+
+void 
+xform_mtx2 (GRFMTX_2D m, double& x, double& y)
+{
+  double xt = x * m[0][0] + y * m[1][0] + m[2][0];
+  double yt = x * m[0][1] + y * m[1][1] + m[2][1];
+
+  x = xt;
+  y = yt;
+}