Added template MATRIX3x3 for handling general 3x3 matrices (for future usage in GAL)

include/math/matrix3x3.h

+/*
+ * This program source code file is part of KICAD, a free EDA CAD application.
+ *
+ * Copyright (C) 2012 Torsten Hueter, torstenhtr <at> gmx.de
+ * Copyright (C) 2012 Kicad Developers, see change_log.txt for contributors.
+ *
+ * Matrix class (3x3)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, you may find one here:
+ * http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
+ * or you may search the http://www.gnu.org website for the version 2 license,
+ * or you may write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
+ */
+
+#ifndef MATRIX3X3_H_
+#define MATRIX3X3_H_
+
+#include <math/vector2d.h>
+
+/**
+ * Class MATRIX3x3 describes a general 3x3 matrix.
+ *
+ * Any linear transformation in 2D can be represented
+ * by a homogeneous 3x3 transformation matrix. Given a vector x, the linear transformation
+ * with the transformation matrix M is given as
+ *
+ * x' = M * x
+ *
+ * To represent an affine transformation, homogeneous coordinates have to be used. That means
+ * the 2D-vector (x, y) has to be extended to a 3D-vector by a third component (x, y, 1).
+ *
+ * Transformations can be easily combined by matrix multiplication.
+ *
+ * A * (B * x ) = (A * B) * x
+ * ( A, B: transformation matrices, x: vector )
+ *
+ * This class was implemented using templates, so flexible type combinations are possible.
+ *
+ */
+
+// Forward declaration for template friends
+template <class T> class MATRIX3x3;
+template <class T> std::ostream& operator<<( std::ostream& stream, const MATRIX3x3<T>& matrix );
+
+template <class T>
+class MATRIX3x3
+{
+public:
+    T m_data[3][3];
+
+    /**
+     * @brief Constructor
+     *
+     * Initialize all matrix members to zero.
+     */
+    MATRIX3x3();
+
+    /**
+     * @brief Constructor
+     *
+     * Initialize with given matrix members
+     *
+     * @param a00 is the component [0,0].
+     * @param a01 is the component [0,1].
+     * @param a02 is the component [0,2].
+     * @param a11 is the component [1,1].
+     * @param a12 is the component [1,2].
+     * @param a13 is the component [1,3].
+     * @param a20 is the component [2,0].
+     * @param a21 is the component [2,1].
+     * @param a00 is the component [2,2].
+     */
+    MATRIX3x3( T a00, T a01, T a02, T a10, T a11, T a12, T a20, T a21, T a22 );
+
+    /**
+     * @brief Set the matrix to the identity matrix.
+     *
+     * The diagonal components of the matrix are set to 1.
+     */
+    void SetIdentity( void );
+
+    /**
+     * @brief Set the translation components of the matrix.
+     *
+     * @param aTranslation is the translation, specified as 2D-vector.
+     */
+    void SetTranslation( VECTOR2<T> aTranslation );
+
+    /**
+     * @brief Get the translation components of the matrix.
+     *
+     * @return is the translation (2D-vector).
+     */
+    VECTOR2<T> GetTranslation( void ) const;
+
+    /**
+     * @brief Set the rotation components of the matrix.
+     *
+     * The angle needs to have a positive value for an anti-clockwise rotation.
+     *
+     * @param aAngle is the rotation angle in [rad].
+     */
+    void SetRotation( T aAngle );
+
+    /**
+     * @brief Set the scale components of the matrix.
+     *
+     * @param aScale contains the scale factors, specified as 2D-vector.
+     */
+    void SetScale( VECTOR2<T> aScale );
+
+    /**
+     * @brief Get the scale components of the matrix.
+     *
+     * @return the scale factors, specified as 2D-vector.
+     */
+    VECTOR2<T> GetScale( void ) const;
+
+    /**
+     * @brief Compute the determinant of the matrix.
+     *
+     * @return the determinant value.
+     */
+    T Determinant( void ) const;
+
+    /**
+     * @brief Determine the inverse of the matrix.
+     *
+     * The inverse of a transformation matrix can be used to revert a transformation.
+     *
+     * x = Minv * ( M * x )
+     * ( M: transformation matrix, Minv: inverse transformation matrix, x: vector)
+     *
+     * @return the inverse matrix.
+     */
+    MATRIX3x3 Inverse( void ) const;
+
+    /**
+     * @brief Get the transpose of the matrix.
+     *
+     * @return the transpose matrix.
+     */
+    MATRIX3x3 Transpose( void ) const;
+
+    /**
+     * @brief Output to a stream.
+     */
+    friend std::ostream& operator<<<T>( std::ostream& stream, const MATRIX3x3<T>& matrix );
+
+};
+
+// Operators
+
+//! @brief Matrix multiplication
+template<class T> MATRIX3x3<T> const operator*( MATRIX3x3<T> const& a, MATRIX3x3<T> const& b );
+
+//! @brief Multiplication with a 2D vector, the 3rd z-component is assumed to be 1
+template<class T> VECTOR2<T> const operator*( MATRIX3x3<T> const& a, VECTOR2<T> const& b );
+
+//! @brief Multiplication with a scalar
+template<class T, class S> MATRIX3x3<T> const operator*( MATRIX3x3<T> const& a, T scalar );
+template<class T, class S> MATRIX3x3<T> const operator*( T scalar, MATRIX3x3<T> const& matrix );
+
+// ----------------------
+// --- Implementation ---
+// ----------------------
+
+template<class T> MATRIX3x3<T>::MATRIX3x3()
+{
+    for( int j = 0; j < 3; j++ )
+    {
+        for( int i = 0; i < 3; i++ )
+        {
+            m_data[i][j] = 0.0;
+        }
+    }
+}
+
+
+template<class T> MATRIX3x3<T>::MATRIX3x3( T a00, T a01, T a02, T a10, T a11, T a12, T a20, T a21,
+                                           T a22 )
+{
+    m_data[0][0] = a00;
+    m_data[0][1] = a01;
+    m_data[0][2] = a02;
+
+    m_data[1][0] = a10;
+    m_data[1][1] = a11;
+    m_data[1][2] = a12;
+
+    m_data[2][0] = a20;
+    m_data[2][1] = a21;
+    m_data[2][2] = a22;
+}
+
+
+template<class T> void MATRIX3x3<T>::SetIdentity( void )
+{
+    for( int j = 0; j < 3; j++ )
+    {
+        for( int i = 0; i < 3; i++ )
+        {
+            if( i == j )
+                m_data[i][j] = 1.0;
+            else
+                m_data[i][j] = 0.0;
+        }
+    }
+}
+
+
+template<class T> void MATRIX3x3<T>::SetTranslation( VECTOR2<T> aTranslation )
+{
+    m_data[0][2] = aTranslation.x;
+    m_data[1][2] = aTranslation.y;
+}
+
+
+template<class T> VECTOR2<T> MATRIX3x3<T>::GetTranslation( void ) const
+{
+    VECTOR2<T> result;
+    result.x = m_data[0][2];
+    result.y = m_data[1][2];
+    return result;
+}
+
+
+template<class T> void MATRIX3x3<T>::SetRotation( T aAngle )
+{
+    T cosValue = cos( aAngle );
+    T sinValue = sin( aAngle );
+    m_data[0][0] = cosValue;
+    m_data[0][1] = -sinValue;
+    m_data[1][0] = sinValue;
+    m_data[1][1] = cosValue;
+}
+
+
+template<class T> void MATRIX3x3<T>::SetScale( VECTOR2<T> aScale )
+{
+    m_data[0][0] = aScale.x;
+    m_data[1][1] = aScale.y;
+}
+
+
+template<class T> VECTOR2<T> MATRIX3x3<T>::GetScale( void ) const
+{
+    VECTOR2<T> result( m_data[0][0], m_data[1][1] );
+    return result;
+}
+
+
+template<class T> MATRIX3x3<T> const operator*( MATRIX3x3<T> const& a, MATRIX3x3<T> const& b )
+{
+    MATRIX3x3<T> result;
+
+    for( int i = 0; i < 3; i++ )
+    {
+        for( int j = 0; j < 3; j++ )
+        {
+            result.m_data[i][j] = a.m_data[i][0] * b.m_data[0][j] + a.m_data[i][1] * b.m_data[1][j]
+                                  + a.m_data[i][2] * b.m_data[2][j];
+        }
+    }
+
+    return result;
+}
+
+
+template<class T> VECTOR2<T> const operator*( MATRIX3x3<T> const& matrix,
+                                              VECTOR2<T> const& vector )
+{
+    VECTOR2<T> result( 0, 0 );
+    result.x = matrix.m_data[0][0] * vector.x + matrix.m_data[0][1] * vector.y
+               + matrix.m_data[0][2];
+    result.y = matrix.m_data[1][0] * vector.x + matrix.m_data[1][1] * vector.y
+               + matrix.m_data[1][2];
+
+    return result;
+}
+
+
+template<class T> T MATRIX3x3<T>::Determinant( void ) const
+{
+    return m_data[0][0] * ( m_data[1][1] * m_data[2][2] - m_data[1][2] * m_data[2][1] )
+           - m_data[0][1] * ( m_data[1][0] * m_data[2][2] - m_data[1][2] * m_data[2][0] )
+           + m_data[0][2] * ( m_data[1][0] * m_data[2][1] - m_data[1][1] * m_data[2][0] );
+}
+
+
+template<class T, class S> MATRIX3x3<T> const operator*( MATRIX3x3<T> const& matrix, S scalar )
+{
+    MATRIX3x3<T> result;
+
+    for( int i = 0; i < 3; i++ )
+    {
+        for( int j = 0; j < 3; j++ )
+        {
+            result.m_data[i][j] = matrix.m_data[i][j] * scalar;
+        }
+    }
+
+    return result;
+}
+
+
+template<class T, class S> MATRIX3x3<T> const operator*( S scalar, MATRIX3x3<T> const& matrix )
+{
+    return matrix * scalar;
+}
+
+
+template<class T> MATRIX3x3<T> MATRIX3x3<T>::Inverse( void ) const
+{
+    MATRIX3x3<T> result;
+
+    result.m_data[0][0] = m_data[1][1] * m_data[2][2] - m_data[2][1] * m_data[1][2];
+    result.m_data[0][1] = m_data[0][2] * m_data[2][1] - m_data[2][2] * m_data[0][1];
+    result.m_data[0][2] = m_data[0][1] * m_data[1][2] - m_data[1][1] * m_data[0][2];
+
+    result.m_data[1][0] = m_data[1][2] * m_data[2][0] - m_data[2][2] * m_data[1][0];
+    result.m_data[1][1] = m_data[0][0] * m_data[2][2] - m_data[2][0] * m_data[0][2];
+    result.m_data[1][2] = m_data[0][2] * m_data[1][0] - m_data[1][2] * m_data[0][0];
+
+    result.m_data[2][0] = m_data[1][0] * m_data[2][1] - m_data[2][0] * m_data[1][1];
+    result.m_data[2][1] = m_data[0][1] * m_data[2][0] - m_data[2][1] * m_data[0][0];
+    result.m_data[2][2] = m_data[0][0] * m_data[1][1] - m_data[1][0] * m_data[0][1];
+
+    return result * ( 1.0 / Determinant() );
+}
+
+
+template<class T> MATRIX3x3<T> MATRIX3x3<T>::Transpose( void ) const
+{
+    MATRIX3x3<T> result;
+
+    for( int i = 0; i < 3; i++ )
+    {
+        for( int j = 0; j < 3; j++ )
+        {
+            result.m_data[j][i] = m_data[i][j];
+        }
+    }
+
+    return result;
+}
+
+
+template<class T> std::ostream& operator<<( std::ostream& aStream, const MATRIX3x3<T>& aMatrix )
+{
+    for( int i = 0; i < 3; i++ )
+    {
+        aStream << "| ";
+
+        for( int j = 0; j < 3; j++ )
+        {
+            aStream << aMatrix.m_data[i][j];
+            aStream << " ";
+        }
+
+        aStream << "|";
+        aStream << "\n";
+    }
+
+    return aStream;
+}
+
+/* Default specializations */
+typedef MATRIX3x3<double> MATRIX3x3D;
+
+#endif /* MATRIX3X3_H_ */