src/common/affinematrix2d.cpp

   1 ///////////////////////////////////////////////////////////////////////////////
   2 // Name:        affinematrix2d.cpp
   3 // Purpose:     implementation of wxAffineMatrix2D
   4 // Author:      Based on wxTransformMatrix by Chris Breeze, Julian Smart
   5 // Created:     2011-04-05
   6 // Copyright:   (c) wxWidgets team
   7 // Licence:     wxWindows licence
   8 ///////////////////////////////////////////////////////////////////////////////
   9
  10 #include "wx/wxprec.h"
  11
  12 #ifdef __BORLANDC__
  13     #pragma hdrstop
  14 #endif
  15
  16 #if wxUSE_GEOMETRY
  17
  18 #include "wx/affinematrix2d.h"
  19 #include "wx/math.h"
  20
  21 // sets the matrix to the respective values
  22 void wxAffineMatrix2D::Set(const wxMatrix2D &mat2D, const wxPoint2DDouble &tr)
  23 {
  24     m_11 = mat2D.m_11;
  25     m_12 = mat2D.m_12;
  26     m_21 = mat2D.m_21;
  27     m_22 = mat2D.m_22;
  28     m_tx = tr.m_x;
  29     m_ty = tr.m_y;
  30 }
  31
  32 // gets the component valuess of the matrix
  33 void wxAffineMatrix2D::Get(wxMatrix2D *mat2D, wxPoint2DDouble *tr) const
  34 {
  35     mat2D->m_11 = m_11;
  36     mat2D->m_12 = m_12;
  37     mat2D->m_21 = m_21;
  38     mat2D->m_22 = m_22;
  39
  40     if ( tr )
  41     {
  42         tr->m_x = m_tx;
  43         tr->m_y = m_ty;
  44     }
  45 }
  46
  47 // concatenates the matrix
  48 // | t.m_11  t.m_12  0 |   | m_11  m_12   0 |
  49 // | t.m_21  t.m_22  0 | x | m_21  m_22   0 |
  50 // | t.m_tx  t.m_ty  1 |   | m_tx  m_ty   1 |
  51 void wxAffineMatrix2D::Concat(const wxAffineMatrix2DBase &t)
  52 {
  53     wxMatrix2D mat;
  54     wxPoint2DDouble tr;
  55     t.Get(&mat, &tr);
  56
  57     m_tx += tr.m_x*m_11 + tr.m_y*m_21;
  58     m_ty += tr.m_x*m_12 + tr.m_y*m_22;
  59     wxDouble e11 = mat.m_11*m_11 + mat.m_12*m_21;
  60     wxDouble e12 = mat.m_11*m_12 + mat.m_12*m_22;
  61     wxDouble e21 = mat.m_21*m_11 + mat.m_22*m_21;
  62     m_22 = mat.m_21*m_12 + mat.m_22*m_22;
  63     m_11 = e11;
  64     m_12 = e12;
  65     m_21 = e21;
  66 }
  67
  68 // makes this its inverse matrix.
  69 // Invert
  70 // | m_11  m_12   0 |
  71 // | m_21  m_22   0 |
  72 // | m_tx  m_ty   1 |
  73 bool wxAffineMatrix2D::Invert()
  74 {
  75     const wxDouble det = m_11*m_22 - m_12*m_21;
  76
  77     if ( !det )
  78         return false;
  79
  80     wxDouble ex = (m_21*m_ty - m_22*m_tx) / det;
  81     m_ty = (-m_11*m_ty + m_12*m_tx) / det;
  82     m_tx = ex;
  83     wxDouble e11 = m_22 / det;
  84     m_12 = -m_12 / det;
  85     m_21 = -m_21 / det;
  86     m_22 = m_11 / det;
  87     m_11 = e11;
  88
  89     return true;
  90 }
  91
  92 // returns true if the elements of the transformation matrix are equal
  93 bool wxAffineMatrix2D::IsEqual(const wxAffineMatrix2DBase& t) const
  94 {
  95     wxMatrix2D mat;
  96     wxPoint2DDouble tr;
  97     t.Get(&mat, &tr);
  98
  99     return m_11 == mat.m_11 && m_12 == mat.m_12 &&
 100            m_21 == mat.m_21 && m_22 == mat.m_22 &&
 101            m_tx == tr.m_x && m_ty == tr.m_y;
 102 }
 103
 104 //
 105 // transformations
 106 //
 107
 108 // add the translation to this matrix
 109 void wxAffineMatrix2D::Translate(wxDouble dx, wxDouble dy)
 110 {
 111     m_tx += dx;
 112     m_ty += dy;
 113 }
 114
 115 // add the scale to this matrix
 116 // | xScale   0      0 |   | m_11  m_12   0 |
 117 // |   0    yScale   0 | x | m_21  m_22   0 |
 118 // |   0      0      1 |   | m_tx  m_ty   1 |
 119 void wxAffineMatrix2D::Scale(wxDouble xScale, wxDouble yScale)
 120 {
 121     m_11 *= xScale;
 122     m_12 *= xScale;
 123     m_21 *= yScale;
 124     m_22 *= yScale;
 125 }
 126
 127 // add the rotation to this matrix (counter clockwise, radians)
 128 // | cos   -sin   0 |   | m_11  m_12   0 |
 129 // | sin    cos   0 | x | m_21  m_22   0 |
 130 // |  0      0    1 |   | m_tx  m_ty   1 |
 131 void wxAffineMatrix2D::Rotate(wxDouble ccRadians)
 132 {
 133     wxDouble c = cos(ccRadians);
 134     wxDouble s = sin(ccRadians);
 135
 136     wxDouble e11 = c*m_11 - s*m_21;
 137     wxDouble e12 = c*m_12 - s*m_22;
 138     m_21 = s*m_11 + c*m_21;
 139     m_22 = s*m_12 + c*m_22;
 140     m_11 = e11;
 141     m_12 = e12;
 142 }
 143
 144 //
 145 // apply the transforms
 146 //
 147
 148 // applies that matrix to the point
 149 //                           | m_11  m_12   0 |
 150 // | src.m_x  src._my  1 | x | m_21  m_22   0 |
 151 //                           | m_tx  m_ty   1 |
 152 wxPoint2DDouble
 153 wxAffineMatrix2D::DoTransformPoint(const wxPoint2DDouble& src) const
 154 {
 155     if ( IsIdentity() )
 156         return src;
 157
 158     return wxPoint2DDouble(src.m_x * m_11 + src.m_y * m_21 + m_tx,
 159                            src.m_y * m_12 + src.m_y * m_22 + m_ty);
 160 }
 161
 162 // applies the matrix except for translations
 163 //                           | m_11  m_12   0 |
 164 // | src.m_x  src._my  0 | x | m_21  m_22   0 |
 165 //                           | m_tx  m_ty   1 |
 166 wxPoint2DDouble
 167 wxAffineMatrix2D::DoTransformDistance(const wxPoint2DDouble& src) const
 168 {
 169     if ( IsIdentity() )
 170         return src;
 171
 172     return wxPoint2DDouble(src.m_x * m_11 + src.m_y * m_21,
 173                            src.m_y * m_12 + src.m_y * m_22);
 174 }
 175
 176 bool wxAffineMatrix2D::IsIdentity() const
 177 {
 178     return m_11 == 1 && m_12 == 0 &&
 179            m_21 == 0 && m_22 == 1 &&
 180            m_tx == 0 && m_ty == 0;
 181 }
 182
 183 #endif // wxUSE_GEOMETRY