offapi/com/sun/star/geometry/Matrix2D.idl

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  28 #ifndef __com_sun_star_geometry_Matrix2D_idl__
  29 #define __com_sun_star_geometry_Matrix2D_idl__
  30
  31 module com {  module sun {  module star {  module geometry {
  32
  33 /** This structure defines a 2 by 2 matrix.<p>
  34
  35     This constitutes a linear mapping of a point in 2D to another
  36     point in 2D.<p>
  37
  38     The matrix defined by this structure constitutes a linear
  39     mapping of a point in 2D to another point in 2D. In contrast to
  40     the <type>com.sun.star.geometry.AffineMatrix2D</type>, this
  41     matrix does not include any translational components.<p>
  42
  43     A linear mapping, as performed by this matrix, can be written out
  44     as follows, where <code>xs</code> and <code>ys</code> are the source, and
  45     <code>xd</code> and <code>yd</code> the corresponding result coordinates:
  46
  47     <code>
  48         xd = m00*xs + m01*ys;
  49         yd = m10*xs + m11*ys;
  50     </code><p>
  51
  52     Thus, in common matrix language, with M being the
  53     <type>Matrix2D</type> and vs=[xs,ys]^T, vd=[xd,yd]^T two 2D
  54     vectors, the linear mapping is written as
  55     vd=M*vs. Concatenation of transformations amounts to
  56     multiplication of matrices, i.e. a scaling, given by S,
  57     followed by a rotation, given by R, is expressed as vd=R*(S*vs) in
  58     the above notation. Since matrix multiplication is associative,
  59     this can be shortened to vd=(R*S)*vs=M'*vs. Therefore, a set of
  60     consecutive transformations can be accumulated into a single
  61     Matrix2D, by multiplying the current transformation with the
  62     additional transformation from the left.<p>
  63
  64     Due to this transformational approach, all geometry data types are
  65     points in abstract integer or real coordinate spaces, without any
  66     physical dimensions attached to them. This physical measurement
  67     units are typically only added when using these data types to
  68     render something onto a physical output device, like a screen or a
  69     printer. Then, the total transformation matrix and the device
  70     resolution determine the actual measurement unit.<p>
  71
  72     @since OOo 2.0
  73  */
  74 struct Matrix2D
  75 {
  76     /// The top, left matrix entry.
  77     double m00;
  78
  79     /// The top, right matrix entry.
  80     double m01;
  81
  82     /// The bottom, left matrix entry.
  83     double m10;
  84
  85     /// The bottom, right matrix entry.
  86     double m11;
  87 };
  88
  89 }; }; }; };
  90
  91 #endif
  92
  93 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */