Line data    Source code

       1             : /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
       2             : /* This Source Code Form is subject to the terms of the Mozilla Public
       3             :  * License, v. 2.0. If a copy of the MPL was not distributed with this
       4             :  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
       5             : 
       6             : #ifndef nsTransform2D_h___
       7             : #define nsTransform2D_h___
       8             : 
       9             : #include "nsCoord.h"
      10             : 
      11             : class nsTransform2D
      12             : {
      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           0 :   nsTransform2D(void)                         { m20 = m21 = 0.0f; m00 = m11 = 1.0f; }
      30             : 
      31           0 :   ~nsTransform2D(void)                        { }
      32             : 
      33             :  /**
      34             :   * set this transform to a translation
      35             :   *
      36             :   * @param      tx, x translation
      37             :   * @param      ty, y translation
      38             :   **/
      39             : 
      40           0 :   void SetToTranslate(float tx, float ty)    { m00 = m11 = 1.0f; m20 = tx; m21 = ty; }
      41             :   
      42             :  /**
      43             :   * get the translation portion of this transform
      44             :   *
      45             :   * @param      pt, Point to return translation values in
      46             :   **/
      47             : 
      48             :   void GetTranslationCoord(nscoord *ptX, nscoord *ptY) const { *ptX = NSToCoordRound(m20); *ptY = NSToCoordRound(m21); }
      49             : 
      50             :  /**
      51             :   * apply matrix to vector
      52             :   *
      53             :   * @param    pt Point to transform
      54             :   **/
      55             : 
      56             :   void TransformCoord(nscoord *ptX, nscoord *ptY) const;
      57             : 
      58             :  /**
      59             :   * apply matrix to rect
      60             :   *
      61             :   * @param    rect Rect to transform
      62             :   **/
      63             : 
      64             :   void TransformCoord(nscoord *aX, nscoord *aY, nscoord *aWidth, nscoord *aHeight) const;
      65             : 
      66             :  /**
      67             :   * add a scale to a Transform via x, y pair
      68             :   *
      69             :   * @param    ptX x value to add as x scale
      70             :   * @param    ptY y value to add as y scale
      71             :   **/
      72             : 
      73             :   void AddScale(float ptX, float ptY) { m00 *= ptX; m11 *= ptY; }
      74             : 
      75             :  /**
      76             :   * Set the scale (overriding any previous calls to AddScale, but leaving
      77             :   * any existing translation).
      78             :   *
      79             :   * @param    ptX x value to add as x scale
      80             :   * @param    ptY y value to add as y scale
      81             :   **/
      82             : 
      83           0 :   void SetScale(float ptX, float ptY) { m00 = ptX; m11 = ptY; }
      84             : };
      85             : 
      86             : #endif