1 /* 2 * affine.h -- ePiX::affine class (affine screen maps) 3 * 4 * This file is part of ePiX, a C++ library for creating high-quality 5 * figures in LaTeX 6 * 7 * Version 1.1.21 8 * Last Change: September 23, 2007 9 * 10 * 11 * Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007 12 * Andrew D. Hwang <rot 13 nujnat at zngupf dot ubylpebff dot rqh> 13 * Department of Mathematics and Computer Science 14 * College of the Holy Cross 15 * Worcester, MA, 01610-2395, USA 16 * 17 * 18 * ePiX is free software; you can redistribute it and/or modify it 19 * under the terms of the GNU General Public License as published by 20 * the Free Software Foundation; either version 2 of the License, or 21 * (at your option) any later version. 22 * 23 * ePiX is distributed in the hope that it will be useful, but WITHOUT 24 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 25 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public 26 * License for more details. 27 * 28 * You should have received a copy of the GNU General Public License 29 * along with ePiX; if not, write to the Free Software Foundation, Inc., 30 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 31 */ 32 33 /* 34 * An affine map is constructed from the images of the "standard 35 * triple" (0,0), (1,0), and (0,1). 36 * 37 * An affine map may be (post)-composed with translation, rotation, 38 * reflection, scaling along either or both coordinate axes, shearing, 39 * and may be inverted. An optional pair argument, defaulting to 40 * (0,0), gives the center of the operation (if appropriate). 41 * 42 * An affine map may be post-composed via member function, and 43 * pre-composed with operator syntax. The evaluation operator 44 * returns the image of the argument. 45 */ 46 47 #ifndef EPIX_AFFINE 48 #define EPIX_AFFINE 49 50 #include "pairs.h" 51 #include "triples.h" 52 53 namespace ePiX { 54 55 class affine { 56 public: 57 // the identity map 58 affine(); 59 60 // images of (1,0), (0,1), (0,0) 61 affine(const pair&, const pair&, const pair& loc=pair(0,0)); 62 affine(const P&, const P&, const P& loc=P(0,0)); 63 64 // post-operations 65 // translate by arg 66 affine& shift(const pair& arg); 67 affine& shift(const P& arg); 68 69 // rotate by theta about ctr 70 affine& rotate(double theta, const pair& ctr = pair(0,0)); 71 affine& rotate(double theta, const P& ctr); 72 73 // reflect in angle-theta line through ctr 74 affine& reflect(double theta, const pair& ctr = pair(0,0)); 75 affine& reflect(double theta, const P& ctr); 76 77 // scale coord direction(s) fixing ctr 78 affine& h_scale(double, const pair& ctr=pair(0,0)); 79 affine& v_scale(double, const pair& ctr=pair(0,0)); 80 affine& scale(double, const pair& ctr=pair(0,0)); 81 82 affine& h_scale(double, const P& ctr); 83 affine& v_scale(double, const P& ctr); 84 affine& scale(double, const P& ctr); 85 86 // shear, fixing ctr 87 affine& h_shear(double, const pair& ctr=pair(0,0)); 88 affine& v_shear(double, const pair& ctr=pair(0,0)); 89 90 affine& h_shear(double, const P& ctr); 91 affine& v_shear(double, const P& ctr); 92 93 // post-compose 94 affine& postcomp(const affine&); 95 96 affine& invert(); 97 98 // evaluation 99 pair operator() (const pair&) const; 100 pair operator() (const P&) const; 101 102 // pre-compose 103 affine operator() (const affine&) const; 104 105 bool reverses_orientation() const; 106 107 private: 108 pair m_00; 109 pair m_10; 110 pair m_01; 111 }; 112 } // end of ePiX namespace 113 114 #endif /* EPIX_AFFINE */ 115