gfx/src/nsTransform2D.h

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  23  *      michaelp   09-25-97 1:56pm
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  38
  39 #ifndef nsTransform2D_h___
  40 #define nsTransform2D_h___
  41
  42 #include "gfxCore.h"
  43 #include "nsCoord.h"
  44
  45 class NS_GFX nsTransform2D
  46 {
  47 private:
  48  /**
  49   * This represents the following matrix (note that the order of row/column
  50   * indices is opposite to usual notation)
  51   *
  52   *      / m00   0   m20  \
  53   * M =  |  0   m11  m21  |
  54   *      \  0    0    1   /
  55   *
  56   * Transformation of a coordinate (x, y) is obtained by setting
  57   * v = (x, y, 1)^T and evaluating  M . v
  58   **/
  59
  60   float     m00, m11, m20, m21;
  61
  62 public:
  63   nsTransform2D(void)                         { m20 = m21 = 0.0f; m00 = m11 = 1.0f; }
  64   nsTransform2D(nsTransform2D *aTransform2D)  {
  65     m00 = aTransform2D->m00;
  66     m11 = aTransform2D->m11;
  67     m20 = aTransform2D->m20;
  68     m21 = aTransform2D->m21;
  69   }
  70
  71   ~nsTransform2D(void)                        { }
  72
  73  /**
  74   * set this transform to a translation
  75   *
  76   * @param      tx, x translation
  77   * @param      ty, y translation
  78   **/
  79
  80   void SetToTranslate(float tx, float ty)    { m00 = m11 = 1.0f; m20 = tx; m21 = ty; }
  81
  82  /**
  83   * get the translation portion of this transform
  84   *
  85   * @param      pt, Point to return translation values in
  86   **/
  87
  88   void GetTranslationCoord(nscoord *ptX, nscoord *ptY) const { *ptX = NSToCoordRound(m20); *ptY = NSToCoordRound(m21); }
  89
  90  /**
  91   * apply matrix to vector
  92   *
  93   * @param    pt Point to transform
  94   **/
  95
  96   void TransformCoord(nscoord *ptX, nscoord *ptY) const;
  97
  98  /**
  99   * apply matrix to rect
 100   *
 101   * @param    rect Rect to transform
 102   **/
 103
 104   void TransformCoord(nscoord *aX, nscoord *aY, nscoord *aWidth, nscoord *aHeight) const;
 105
 106  /**
 107   * add a scale to a Transform via x, y pair
 108   *
 109   * @param    ptX x value to add as x scale
 110   * @param    ptY y value to add as y scale
 111   **/
 112
 113   void AddScale(float ptX, float ptY) { m00 *= ptX; m11 *= ptY; }
 114
 115  /**
 116   * Set the scale (overriding any previous calls to AddScale, but leaving
 117   * any existing translation).
 118   *
 119   * @param    ptX x value to add as x scale
 120   * @param    ptY y value to add as y scale
 121   **/
 122
 123   void SetScale(float ptX, float ptY) { m00 = ptX; m11 = ptY; }
 124 };
 125
 126 #endif