87 lines
2.1 KiB
C++
87 lines
2.1 KiB
C++
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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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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#ifndef nsTransform2D_h___
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#define nsTransform2D_h___
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#include "nsCoord.h"
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class nsTransform2D
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{
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private:
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/**
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* This represents the following matrix (note that the order of row/column
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* indices is opposite to usual notation)
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*
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* / m00 0 m20 \
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* M = | 0 m11 m21 |
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* \ 0 0 1 /
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*
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* Transformation of a coordinate (x, y) is obtained by setting
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* v = (x, y, 1)^T and evaluating M . v
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**/
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float m00, m11, m20, m21;
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public:
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nsTransform2D(void) { m20 = m21 = 0.0f; m00 = m11 = 1.0f; }
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~nsTransform2D(void) { }
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/**
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* set this transform to a translation
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*
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* @param tx, x translation
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* @param ty, y translation
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**/
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void SetToTranslate(float tx, float ty) { m00 = m11 = 1.0f; m20 = tx; m21 = ty; }
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/**
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* get the translation portion of this transform
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*
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* @param pt, Point to return translation values in
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**/
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void GetTranslationCoord(nscoord *ptX, nscoord *ptY) const { *ptX = NSToCoordRound(m20); *ptY = NSToCoordRound(m21); }
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/**
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* apply matrix to vector
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*
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* @param pt Point to transform
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**/
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void TransformCoord(nscoord *ptX, nscoord *ptY) const;
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/**
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* apply matrix to rect
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*
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* @param rect Rect to transform
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**/
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void TransformCoord(nscoord *aX, nscoord *aY, nscoord *aWidth, nscoord *aHeight) const;
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/**
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* add a scale to a Transform via x, y pair
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*
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* @param ptX x value to add as x scale
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* @param ptY y value to add as y scale
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**/
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void AddScale(float ptX, float ptY) { m00 *= ptX; m11 *= ptY; }
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/**
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* Set the scale (overriding any previous calls to AddScale, but leaving
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* any existing translation).
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*
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* @param ptX x value to add as x scale
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* @param ptY y value to add as y scale
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**/
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void SetScale(float ptX, float ptY) { m00 = ptX; m11 = ptY; }
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};
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#endif
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