include/wx/matrix.h

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        matrix.h
   3 // Purpose:     wxTransformMatrix class. NOT YET USED
   4 // Author:      Chris Breeze, Julian Smart
   5 // Modified by:  Klaas Holwerda
   6 // Created:     01/02/97
   7 // RCS-ID:      $Id$
   8 // Copyright:   (c) Julian Smart, Chris Breeze
   9 // Licence:     wxWindows licence
  10 /////////////////////////////////////////////////////////////////////////////
  11
  12 #ifndef _WX_MATRIXH__
  13 #define _WX_MATRIXH__
  14
  15 //! headerfiles="matrix.h wx/object.h"
  16 #include "wx/object.h"
  17
  18 //! codefiles="matrix.cpp"
  19
  20 // A simple 3x3 matrix. This may be replaced by a more general matrix
  21 // class some day.
  22 //
  23 // Note: this is intended to be used in wxDC at some point to replace
  24 // the current system of scaling/translation. It is not yet used.
  25
  26 //:definition
  27 //  A 3x3 matrix to do 2D transformations.
  28 //  It can be used to map data to window coordinates,
  29 //  and also for manipulating your own data.
  30 //  For example drawing a picture (composed of several primitives)
  31 //  at a certain coordinate and angle within another parent picture.
  32 //  At all times m_isIdentity is set if the matrix itself is an Identity matrix.
  33 //  It is used where possible to optimize calculations.
  34 class WXDLLEXPORT wxTransformMatrix: public wxObject
  35 {
  36 public:
  37     wxTransformMatrix(void);
  38     wxTransformMatrix(const wxTransformMatrix& mat);
  39
  40     //get the value in the matrix at col,row
  41     //rows are horizontal (second index of m_matrix member)
  42     //columns are vertical (first index of m_matrix member)
  43     double GetValue(int col, int row) const;
  44
  45     //set the value in the matrix at col,row
  46     //rows are horizontal (second index of m_matrix member)
  47     //columns are vertical (first index of m_matrix member)
  48     void SetValue(int col, int row, double value);
  49
  50     void operator = (const wxTransformMatrix& mat);
  51     bool operator == (const wxTransformMatrix& mat) const;
  52     bool operator != (const wxTransformMatrix& mat) const;
  53
  54     //multiply every element by t
  55     wxTransformMatrix&          operator*=(const double& t);
  56     //divide every element by t
  57     wxTransformMatrix&          operator/=(const double& t);
  58     //add matrix m to this t
  59     wxTransformMatrix&          operator+=(const wxTransformMatrix& m);
  60     //subtract matrix m from this
  61     wxTransformMatrix&          operator-=(const wxTransformMatrix& m);
  62     //multiply matrix m with this
  63     wxTransformMatrix&          operator*=(const wxTransformMatrix& m);
  64
  65     // constant operators
  66
  67     //multiply every element by t  and return result
  68     wxTransformMatrix           operator*(const double& t) const;
  69     //divide this matrix by t and return result
  70     wxTransformMatrix           operator/(const double& t) const;
  71     //add matrix m to this and return result
  72     wxTransformMatrix           operator+(const wxTransformMatrix& m) const;
  73     //subtract matrix m from this and return result
  74     wxTransformMatrix           operator-(const wxTransformMatrix& m) const;
  75     //multiply this by matrix m and return result
  76     wxTransformMatrix           operator*(const wxTransformMatrix& m) const;
  77     wxTransformMatrix           operator-() const;
  78
  79     //rows are horizontal (second index of m_matrix member)
  80     //columns are vertical (first index of m_matrix member)
  81     double& operator()(int col, int row);
  82
  83     //rows are horizontal (second index of m_matrix member)
  84     //columns are vertical (first index of m_matrix member)
  85     double operator()(int col, int row) const;
  86
  87     // Invert matrix
  88     bool Invert(void);
  89
  90     // Make into identity matrix
  91     bool Identity(void);
  92
  93     // Is the matrix the identity matrix?
  94     // Only returns a flag, which is set whenever an operation
  95     // is done.
  96     inline bool IsIdentity(void) const { return m_isIdentity; };
  97
  98     // This does an actual check.
  99     inline bool IsIdentity1(void) const ;
 100
 101     //Scale by scale (isotropic scaling i.e. the same in x and y):
 102     //!ex:
 103     //!code:           | scale  0      0      |
 104     //!code: matrix' = |  0     scale  0      | x matrix
 105     //!code:           |  0     0      scale  |
 106     bool Scale(double scale);
 107
 108     //Scale with center point and x/y scale
 109     //
 110     //!ex:
 111     //!code:           |  xs    0      xc(1-xs) |
 112     //!code: matrix' = |  0    ys      yc(1-ys) | x matrix
 113     //!code:           |  0     0      1        |
 114     wxTransformMatrix&  Scale(const double &xs, const double &ys,const double &xc, const double &yc);
 115
 116     // mirror a matrix in x, y
 117     //!ex:
 118     //!code:           | -1     0      0 |
 119     //!code: matrix' = |  0    -1      0 | x matrix
 120     //!code:           |  0     0      1 |
 121     wxTransformMatrix&  Mirror(bool x=true, bool y=false);
 122     // Translate by dx, dy:
 123     //!ex:
 124     //!code:           | 1  0 dx |
 125     //!code: matrix' = | 0  1 dy | x matrix
 126     //!code:           | 0  0  1 |
 127     bool Translate(double x, double y);
 128
 129     // Rotate clockwise by the given number of degrees:
 130     //!ex:
 131     //!code:           |  cos sin 0 |
 132     //!code: matrix' = | -sin cos 0 | x matrix
 133     //!code:           |   0   0  1 |
 134     bool Rotate(double angle);
 135
 136     //Rotate counter clockwise with point of rotation
 137     //
 138     //!ex:
 139     //!code:           |  cos(r) -sin(r)    x(1-cos(r))+y(sin(r)|
 140     //!code: matrix' = |  sin(r)  cos(r)    y(1-cos(r))-x(sin(r)| x matrix
 141     //!code:           |   0          0                       1 |
 142     wxTransformMatrix&  Rotate(const double &r, const double &x, const double &y);
 143
 144     // Transform X value from logical to device
 145     inline double TransformX(double x) const;
 146
 147     // Transform Y value from logical to device
 148     inline double TransformY(double y) const;
 149
 150     // Transform a point from logical to device coordinates
 151     bool TransformPoint(double x, double y, double& tx, double& ty) const;
 152
 153     // Transform a point from device to logical coordinates.
 154     // Example of use:
 155     //   wxTransformMatrix mat = dc.GetTransformation();
 156     //   mat.Invert();
 157     //   mat.InverseTransformPoint(x, y, x1, y1);
 158     // OR (shorthand:)
 159     //   dc.LogicalToDevice(x, y, x1, y1);
 160     // The latter is slightly less efficient if we're doing several
 161     // conversions, since the matrix is inverted several times.
 162     // N.B. 'this' matrix is the inverse at this point
 163     bool InverseTransformPoint(double x, double y, double& tx, double& ty) const;
 164
 165     double Get_scaleX();
 166     double Get_scaleY();
 167     double GetRotation();
 168     void   SetRotation(double rotation);
 169
 170
 171 public:
 172     double  m_matrix[3][3];
 173     bool    m_isIdentity;
 174 };
 175
 176
 177 /*
 178 Chris Breeze reported, that
 179 some functions of wxTransformMatrix cannot work because it is not
 180 known if he matrix has been inverted. Be careful when using it.
 181 */
 182
 183 // Transform X value from logical to device
 184 // warning: this function can only be used for this purpose
 185 // because no rotation is involved when mapping logical to device coordinates
 186 // mirror and scaling for x and y will be part of the matrix
 187 // if you have a matrix that is rotated, eg a shape containing a matrix to place
 188 // it in the logical coordinate system, use TransformPoint
 189 inline double wxTransformMatrix::TransformX(double x) const
 190 {
 191     //normally like this, but since no rotation is involved (only mirror and scale)
 192     //we can do without Y -> m_matrix[1]{0] is -sin(rotation angle) and therefore zero
 193     //(x * m_matrix[0][0] + y * m_matrix[1][0] + m_matrix[2][0]))
 194     return (m_isIdentity ? x : (x * m_matrix[0][0] +  m_matrix[2][0]));
 195 }
 196
 197 // Transform Y value from logical to device
 198 // warning: this function can only be used for this purpose
 199 // because no rotation is involved when mapping logical to device coordinates
 200 // mirror and scaling for x and y will be part of the matrix
 201 // if you have a matrix that is rotated, eg a shape containing a matrix to place
 202 // it in the logical coordinate system, use TransformPoint
 203 inline double wxTransformMatrix::TransformY(double y) const
 204 {
 205     //normally like this, but since no rotation is involved (only mirror and scale)
 206     //we can do without X -> m_matrix[0]{1] is sin(rotation angle) and therefore zero
 207     //(x * m_matrix[0][1] + y * m_matrix[1][1] + m_matrix[2][1]))
 208     return (m_isIdentity ? y : (y * m_matrix[1][1] + m_matrix[2][1]));
 209 }
 210
 211
 212 // Is the matrix the identity matrix?
 213 // Each operation checks whether the result is still the identity matrix and sets a flag.
 214 inline bool wxTransformMatrix::IsIdentity1(void) const
 215 {
 216     return
 217     ( wxIsSameDouble(m_matrix[0][0], 1.0) &&
 218       wxIsSameDouble(m_matrix[1][1], 1.0) &&
 219       wxIsSameDouble(m_matrix[2][2], 1.0) &&
 220       wxIsSameDouble(m_matrix[1][0], 0.0) &&
 221       wxIsSameDouble(m_matrix[2][0], 0.0) &&
 222       wxIsSameDouble(m_matrix[0][1], 0.0) &&
 223       wxIsSameDouble(m_matrix[2][1], 0.0) &&
 224       wxIsSameDouble(m_matrix[0][2], 0.0) &&
 225       wxIsSameDouble(m_matrix[1][2], 0.0) );
 226 }
 227
 228 // Calculates the determinant of a 2 x 2 matrix
 229 inline double wxCalculateDet(double a11, double a21, double a12, double a22)
 230 {
 231     return a11 * a22 - a12 * a21;
 232 }
 233
 234 #endif // _WX_MATRIXH__