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

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
   2 /*
   3  * This file is part of the LibreOffice project.
   4  *
   5  * This Source Code Form is subject to the terms of the Mozilla Public
   6  * License, v. 2.0. If a copy of the MPL was not distributed with this
   7  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
   8  *
   9  * This file incorporates work covered by the following license notice:
  10  *
  11  *   Licensed to the Apache Software Foundation (ASF) under one or more
  12  *   contributor license agreements. See the NOTICE file distributed
  13  *   with this work for additional information regarding copyright
  14  *   ownership. The ASF licenses this file to you under the Apache
  15  *   License, Version 2.0 (the "License"); you may not use this file
  16  *   except in compliance with the License. You may obtain a copy of
  17  *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
  18  */
  19 #ifndef __com_sun_star_geometry_Matrix2D_idl__
  20 #define __com_sun_star_geometry_Matrix2D_idl__
  21
  22 module com {  module sun {  module star {  module geometry {
  23
  24 /** This structure defines a 2 by 2 matrix.<p>
  25
  26     This constitutes a linear mapping of a point in 2D to another
  27     point in 2D.<p>
  28
  29     The matrix defined by this structure constitutes a linear
  30     mapping of a point in 2D to another point in 2D. In contrast to
  31     the com.sun.star.geometry.AffineMatrix2D, this
  32     matrix does not include any translational components.<p>
  33
  34     A linear mapping, as performed by this matrix, can be written out
  35     as follows, where <code>xs</code> and <code>ys</code> are the source, and
  36     <code>xd</code> and <code>yd</code> the corresponding result coordinates:
  37
  38     <code>
  39         xd = m00*xs + m01*ys;
  40         yd = m10*xs + m11*ys;
  41     </code><p>
  42
  43     Thus, in common matrix language, with M being the
  44     Matrix2D and vs=[xs,ys]^T, vd=[xd,yd]^T two 2D
  45     vectors, the linear mapping is written as
  46     vd=M*vs. Concatenation of transformations amounts to
  47     multiplication of matrices, i.e. a scaling, given by S,
  48     followed by a rotation, given by R, is expressed as vd=R*(S*vs) in
  49     the above notation. Since matrix multiplication is associative,
  50     this can be shortened to vd=(R*S)*vs=M'*vs. Therefore, a set of
  51     consecutive transformations can be accumulated into a single
  52     Matrix2D, by multiplying the current transformation with the
  53     additional transformation from the left.<p>
  54
  55     Due to this transformational approach, all geometry data types are
  56     points in abstract integer or real coordinate spaces, without any
  57     physical dimensions attached to them. This physical measurement
  58     units are typically only added when using these data types to
  59     render something onto a physical output device, like a screen or a
  60     printer. Then, the total transformation matrix and the device
  61     resolution determine the actual measurement unit.<p>
  62
  63     @since OOo 2.0
  64  */
  65 struct Matrix2D
  66 {
  67     /// The top, left matrix entry.
  68     double m00;
  69
  70     /// The top, right matrix entry.
  71     double m01;
  72
  73     /// The bottom, left matrix entry.
  74     double m10;
  75
  76     /// The bottom, right matrix entry.
  77     double m11;
  78 };
  79
  80 }; }; }; };
  81
  82 #endif
  83
  84 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */