80 lines
3 KiB
Text
80 lines
3 KiB
Text
/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
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/*
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* This file is part of the LibreOffice project.
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*
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/.
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*
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* This file incorporates work covered by the following license notice:
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed
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* with this work for additional information regarding copyright
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* ownership. The ASF licenses this file to you under the Apache
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* License, Version 2.0 (the "License"); you may not use this file
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* except in compliance with the License. You may obtain a copy of
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* the License at http://www.apache.org/licenses/LICENSE-2.0 .
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*/
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module com { module sun { module star { module geometry {
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/** This structure defines a 2 by 2 matrix.<p>
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This constitutes a linear mapping of a point in 2D to another
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point in 2D.<p>
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The matrix defined by this structure constitutes a linear
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mapping of a point in 2D to another point in 2D. In contrast to
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the com.sun.star.geometry.AffineMatrix2D, this
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matrix does not include any translational components.<p>
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A linear mapping, as performed by this matrix, can be written out
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as follows, where <code>xs</code> and <code>ys</code> are the source, and
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<code>xd</code> and <code>yd</code> the corresponding result coordinates:
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<code>
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xd = m00*xs + m01*ys;
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yd = m10*xs + m11*ys;
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</code><p>
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Thus, in common matrix language, with M being the
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Matrix2D and vs=[xs,ys]^T, vd=[xd,yd]^T two 2D
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vectors, the linear mapping is written as
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vd=M*vs. Concatenation of transformations amounts to
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multiplication of matrices, i.e. a scaling, given by S,
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followed by a rotation, given by R, is expressed as vd=R*(S*vs) in
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the above notation. Since matrix multiplication is associative,
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this can be shortened to vd=(R*S)*vs=M'*vs. Therefore, a set of
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consecutive transformations can be accumulated into a single
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Matrix2D, by multiplying the current transformation with the
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additional transformation from the left.<p>
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Due to this transformational approach, all geometry data types are
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points in abstract integer or real coordinate spaces, without any
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physical dimensions attached to them. This physical measurement
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units are typically only added when using these data types to
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render something onto a physical output device, like a screen or a
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printer. Then, the total transformation matrix and the device
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resolution determine the actual measurement unit.<p>
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@since OOo 2.0
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*/
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struct Matrix2D
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{
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/// The top, left matrix entry.
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double m00;
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/// The top, right matrix entry.
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double m01;
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/// The bottom, left matrix entry.
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double m10;
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/// The bottom, right matrix entry.
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double m11;
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};
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}; }; }; };
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/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
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