nsTransform2D.h (2284B)
1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ 2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */ 3 /* This Source Code Form is subject to the terms of the Mozilla Public 4 * License, v. 2.0. If a copy of the MPL was not distributed with this 5 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ 6 7 #ifndef nsTransform2D_h___ 8 #define nsTransform2D_h___ 9 10 #include "nsCoord.h" 11 12 class nsTransform2D { 13 private: 14 /** 15 * This represents the following matrix (note that the order of row/column 16 * indices is opposite to usual notation) 17 * 18 * / m00 0 m20 \ 19 * M = | 0 m11 m21 | 20 * \ 0 0 1 / 21 * 22 * Transformation of a coordinate (x, y) is obtained by setting 23 * v = (x, y, 1)^T and evaluating M . v 24 **/ 25 26 float m00, m11, m20, m21; 27 28 public: 29 nsTransform2D(void) { 30 m20 = m21 = 0.0f; 31 m00 = m11 = 1.0f; 32 } 33 34 ~nsTransform2D(void) = default; 35 36 /** 37 * set this transform to a translation 38 * 39 * @param tx, x translation 40 * @param ty, y translation 41 **/ 42 43 void SetToTranslate(float tx, float ty) { 44 m00 = m11 = 1.0f; 45 m20 = tx; 46 m21 = ty; 47 } 48 49 /** 50 * get the translation portion of this transform 51 * 52 * @param pt, Point to return translation values in 53 **/ 54 55 void GetTranslationCoord(nscoord* ptX, nscoord* ptY) const { 56 *ptX = NSToCoordRound(m20); 57 *ptY = NSToCoordRound(m21); 58 } 59 60 /** 61 * apply matrix to vector 62 * 63 * @param pt Point to transform 64 **/ 65 66 void TransformCoord(nscoord* ptX, nscoord* ptY) const; 67 68 /** 69 * apply matrix to rect 70 * 71 * @param rect Rect to transform 72 **/ 73 74 void TransformCoord(nscoord* aX, nscoord* aY, nscoord* aWidth, 75 nscoord* aHeight) const; 76 77 /** 78 * add a scale to a Transform via x, y pair 79 * 80 * @param ptX x value to add as x scale 81 * @param ptY y value to add as y scale 82 **/ 83 84 void AddScale(float ptX, float ptY) { 85 m00 *= ptX; 86 m11 *= ptY; 87 } 88 89 /** 90 * Set the scale (overriding any previous calls to AddScale, but leaving 91 * any existing translation). 92 * 93 * @param ptX x value to add as x scale 94 * @param ptY y value to add as y scale 95 **/ 96 97 void SetScale(float ptX, float ptY) { 98 m00 = ptX; 99 m11 = ptY; 100 } 101 }; 102 103 #endif