wxWidgets/include/wx/matrix.h

/////////////////////////////////////////////////////////////////////////////
// Name:        matrix.h
// Purpose:     wxTransformMatrix class. NOT YET USED
// Author:      Chris Breeze, Julian Smart
// Modified by:
// Created:     01/02/97
// RCS-ID:      $Id$
// Copyright:   (c) Julian Smart and Markus Holzem
// Licence:   	wxWindows licence
/////////////////////////////////////////////////////////////////////////////

#ifndef __MATRIXH__
#define __MATRIXH__

#ifdef __GNUG__
#pragma interface "matrix.h"
#endif

#include "wx/object.h"

// A simple 3x3 matrix. This may be replaced by a more general matrix
// class some day.
//
// Note: this is intended to be used in wxDC at some point to replace
// the current system of scaling/translation. It is not yet used.

class WXDLLEXPORT wxTransformMatrix: public wxObject
{
public:
	wxTransformMatrix(void);
	wxTransformMatrix(const wxTransformMatrix& mat);

	double GetValue(int row, int col) const;
	void SetValue(int row, int col, double value);

	void operator = (const wxTransformMatrix& mat);
	bool operator == (const wxTransformMatrix& mat);
	bool operator != (const wxTransformMatrix& mat);

	double& operator()(int row, int col);
	double operator()(int row, int col) const;

	// Invert matrix
	bool Invert(void);

	// Make into identity matrix
	bool Identity(void);

	// Is the matrix the identity matrix?
	// Only returns a flag, which is set whenever an operation
	// is done.
	inline bool IsIdentity(void) const { return m_isIdentity; };

	// This does an actual check.
	inline bool IsIdentity1(void) const ;

	// Isotropic scaling
	bool Scale(double scale);

	// Translate
	bool Translate(double x, double y);

	// Rotate
	bool Rotate(double angle);

	// Transform X value from logical to device
	inline double TransformX(double x) const;

	// Transform Y value from logical to device
	inline double TransformY(double y) const;

	// Transform a point from logical to device coordinates
	bool TransformPoint(double x, double y, double& tx, double& ty) const;

	// Transform a point from device to logical coordinates.

	// Example of use:
	//   wxTransformMatrix mat = dc.GetTransformation();
	//   mat.Invert();
	//   mat.InverseTransformPoint(x, y, x1, y1);
	// OR (shorthand:)
	//   dc.LogicalToDevice(x, y, x1, y1);
	// The latter is slightly less efficient if we're doing several
	// conversions, since the matrix is inverted several times.

	// N.B. 'this' matrix is the inverse at this point

	bool InverseTransformPoint(double x, double y, double& tx, double& ty) const;

public:
    double 	m_matrix[3][3];
	bool	m_isIdentity;
/*
	double m11, m21, m31;
	double m12, m22, m32;
	double m13, m23, m33;
*/
};

// Transform X value from logical to device
inline double wxTransformMatrix::TransformX(double x) const
{
//	return (m_isIdentity ? x : (x * m_matrix[0][0] + y * m_matrix[1][0] + m_matrix[2][0]));
  return 0;
}

// Transform Y value from logical to device
inline double wxTransformMatrix::TransformY(double y) const
{
//	return (m_isIdentity ? y : (x * m_matrix[0][1] + y * m_matrix[1][1] + m_matrix[2][1]));
  return 0;
}

// Is the matrix the identity matrix?
// Perhaps there's some kind of optimization we can do to make this
// a faster operation. E.g. each operation (scale, translate etc.)
// checks whether it's still the identity matrix and sets a flag.
inline bool wxTransformMatrix::IsIdentity1(void) const
{
	return
	 (m_matrix[0][0] == 1.0 &&
	  m_matrix[1][1] == 1.0 &&
	  m_matrix[2][2] == 1.0 &&
	  m_matrix[1][0] == 0.0 &&
	  m_matrix[2][0] == 0.0 &&
	  m_matrix[0][1] == 0.0 &&
	  m_matrix[2][1] == 0.0 &&
	  m_matrix[0][2] == 0.0 &&
	  m_matrix[1][2] == 0.0) ;
}

// Calculates the determinant of a 2 x 2 matrix
inline double wxCalculateDet(double a11, double a21, double a12, double a22)
{
	return a11 * a22 - a12 * a21;
}

#endif
	// __MATRIXH__