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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef nsTransform2D_h___
#define nsTransform2D_h___
#include "nsCoord.h"
class nsTransform2D
{
private:
/**
* This represents the following matrix (note that the order of row/column
* indices is opposite to usual notation)
*
* / m00 0 m20 \
* M = | 0 m11 m21 |
* \ 0 0 1 /
*
* Transformation of a coordinate (x, y) is obtained by setting
* v = (x, y, 1)^T and evaluating M . v
**/
float m00, m11, m20, m21;
public:
nsTransform2D(void) { m20 = m21 = 0.0f; m00 = m11 = 1.0f; }
~nsTransform2D(void) { }
/**
* set this transform to a translation
*
* @param tx, x translation
* @param ty, y translation
**/
void SetToTranslate(float tx, float ty) { m00 = m11 = 1.0f; m20 = tx; m21 = ty; }
/**
* get the translation portion of this transform
*
* @param pt, Point to return translation values in
**/
void GetTranslationCoord(nscoord *ptX, nscoord *ptY) const { *ptX = NSToCoordRound(m20); *ptY = NSToCoordRound(m21); }
/**
* apply matrix to vector
*
* @param pt Point to transform
**/
void TransformCoord(nscoord *ptX, nscoord *ptY) const;
/**
* apply matrix to rect
*
* @param rect Rect to transform
**/
void TransformCoord(nscoord *aX, nscoord *aY, nscoord *aWidth, nscoord *aHeight) const;
/**
* add a scale to a Transform via x, y pair
*
* @param ptX x value to add as x scale
* @param ptY y value to add as y scale
**/
void AddScale(float ptX, float ptY) { m00 *= ptX; m11 *= ptY; }
/**
* Set the scale (overriding any previous calls to AddScale, but leaving
* any existing translation).
*
* @param ptX x value to add as x scale
* @param ptY y value to add as y scale
**/
void SetScale(float ptX, float ptY) { m00 = ptX; m11 = ptY; }
};
#endif
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