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[ctsim.git] / libctgraphics / transformmatrix.cpp

diff --git a/libctgraphics/transformmatrix.cpp b/libctgraphics/transformmatrix.cpp
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+++ b/libctgraphics/transformmatrix.cpp
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+/*****************************************************************************
+** FILE IDENTIFICATION
+**
+**     Name:       transformmatrix.cpp
+**     Function:   Transform Matrix routine for graphic library
+**     Programmer: Kevin Rosenberg
+**     Date Started:   1-22-85
+**
+**  This is part of the CTSim program
+**  Copyright (C) 1983-2000 Kevin Rosenberg
+**
+**  $Id: transformmatrix.cpp,v 1.1 2000/07/28 08:28:08 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 "ctsupport.h"
+#include "transformmatrix.h"
+#include <iostream>
+
+
+TransformationMatrix2D::TransformationMatrix2D (double m[3][3])
+{
+  mtx[0][0] = m[0][0]; mtx[0][1] = m[0][1]; mtx[0][2] = m[0][2];
+  mtx[1][0] = m[1][0]; mtx[1][1] = m[1][1]; mtx[1][2] = m[1][2];
+  mtx[2][0] = m[2][0]; mtx[2][1] = m[2][1]; mtx[2][2] = m[2][2];
+}
+
+void 
+TransformationMatrix2D::setTranslate (double x, double y)
+{
+  setIdentity();
+  mtx[2][0] = x;
+  mtx[2][1] = y;
+}
+
+
+void 
+TransformationMatrix2D::setScale (double sx, double sy)
+{
+  setIdentity();
+  mtx[0][0] = sx;
+  mtx[1][1] = sy;
+}
+
+
+void 
+TransformationMatrix2D::setShear (double shrx, double shry)
+{
+  setIdentity();
+  mtx[1][0] = shrx;
+  mtx[0][1] = shry;
+}
+
+void 
+TransformationMatrix2D::setRotate (double theta)
+{
+    double s = sin (theta);
+    double c = cos (theta);
+
+    setIdentity();
+
+    mtx[0][0] =  c;  mtx[0][1] = s;
+    mtx[1][0] = -s;  mtx[1][1] = c;
+}
+
+
+void 
+TransformationMatrix2D::setIdentity ()
+{
+    mtx[0][0] = 1.;  mtx[0][1] = 0.;  mtx[0][2] = 0.;
+    mtx[1][0] = 0.;  mtx[1][1] = 1.;  mtx[1][2] = 0.;
+    mtx[2][0] = 0.;  mtx[2][1] = 0.;  mtx[2][2] = 1.;
+}
+
+
+const TransformationMatrix2D
+TransformationMatrix2D::invert () const
+{
+  double b[3][3];
+
+  double determ = determinant ();
+  if (fabs(determ) < 1E-6) {
+    sys_error (ERR_WARNING, "Determinant = %g [TransformationMatrix2D::invert]", determ);
+    print (cout);
+    cout << endl;
+  }
+
+  b[0][0] =  (mtx[1][1] * mtx[2][2] - mtx[2][1] * mtx[1][2]) / determ;
+  b[1][0] = -(mtx[1][0] * mtx[2][2] - mtx[2][0] * mtx[1][2]) / determ;
+  b[2][0] =  (mtx[1][0] * mtx[2][1] - mtx[2][0] * mtx[1][1]) / determ;
+  
+  b[0][1] = -(mtx[0][1] * mtx[2][2] - mtx[2][1] * mtx[0][2]) / determ;
+  b[1][1] =  (mtx[0][0] * mtx[2][2] - mtx[2][0] * mtx[0][2]) / determ;
+  b[2][1] = -(mtx[0][0] * mtx[2][1] - mtx[2][0] * mtx[0][1]) / determ;
+      
+  b[0][2] =  (mtx[0][1] * mtx[1][2] - mtx[1][1] * mtx[0][2]) / determ;
+  b[1][2] = -(mtx[0][0] * mtx[1][2] - mtx[1][0] * mtx[0][2]) / determ;
+  b[2][2] =  (mtx[0][0] * mtx[1][1] - mtx[1][0] * mtx[0][1]) / determ;
+
+  return TransformationMatrix2D (b);
+}
+
+
+double 
+TransformationMatrix2D::determinant () const
+{
+  return
+    (mtx[0][0] * mtx[1][1] * mtx[2][2] - mtx[0][0] * mtx[2][1] * mtx[1][2] -
+     mtx[0][1] * mtx[1][0] * mtx[2][2] + mtx[0][1] * mtx[2][0] * mtx[1][2] +
+     mtx[0][2] * mtx[1][0] * mtx[2][1] - mtx[0][2] * mtx[2][0] * mtx[1][1]);
+}
+
+
+void 
+TransformationMatrix2D::transformPoint (double* pX, double *pY) const
+{
+  double x = *pX * mtx[0][0] + *pY * mtx[1][0] + mtx[2][0];
+  double y = *pX * mtx[0][1] + *pY * mtx[1][1] + mtx[2][1];
+
+  *pX = x;
+  *pY = y;
+}
+
+void
+TransformationMatrix2D::print (ostream& ostr) const
+{
+    cout << mtx[0][0] << " " << mtx[0][1] << " " << mtx[0][2] << endl;
+    cout << mtx[1][0] << " " << mtx[1][1] << " " << mtx[1][2] << endl;
+    cout << mtx[2][0] << " " << mtx[2][1] << " " << mtx[2][2] << endl;
+}
+
+
+// Friend of TransformMatrix2D
+
+const TransformationMatrix2D operator* (const TransformationMatrix2D& a, const TransformationMatrix2D& b)
+{
+    double c[3][3];
+
+    for (int row = 0; row < 3; row++)
+      for (int col = 0; col < 3; col++) {
+       c[row][col] = 0.;
+       for (int calc = 0; calc < 3; calc++)
+         c[row][col] += a.mtx[row][calc] * b.mtx[calc][col];
+      }
+
+    return TransformationMatrix2D (c);
+}