include/wx/matrix.h

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