vcl/aqua/source/gdi/salmathutils.cxx

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  30
  31 // MARKER(update_precomp.py): autogen include statement, do not remove
  32 #include "precompiled_vcl.hxx"
  33
  34 #include "salmathutils.hxx"
  35
  36 #include <stdlib.h>
  37
  38 // =======================================================================
  39
  40 // =======================================================================
  41
  42 #define Swap( x, y ) { x ^= y; y ^= x; x ^= y; }
  43
  44 // =======================================================================
  45
  46 // =======================================================================
  47
  48 // Storage free swapping using XOR
  49
  50 void CSwap ( char &rX, char &rY )
  51 {
  52     Swap( rX, rY );
  53 } // CSwap
  54
  55 // -----------------------------------------------------------------------
  56
  57 // Storage free swapping using XOR
  58
  59 void UCSwap ( unsigned char &rX, unsigned char &rY )
  60 {
  61     Swap( rX, rY );
  62 } // UCSwap
  63
  64 // -----------------------------------------------------------------------
  65
  66 // Storage free swapping using XOR
  67
  68 void SSwap ( short &rX, short &rY )
  69 {
  70     Swap( rX, rY );
  71 } // SSwap
  72
  73 // -----------------------------------------------------------------------
  74
  75 // Storage free swapping using XOR
  76
  77 void USSwap ( unsigned short &rX, unsigned short &rY )
  78 {
  79     Swap( rX, rY );
  80 } // USSwap
  81
  82 // -----------------------------------------------------------------------
  83
  84 // Storage free swapping using XOR
  85
  86 void LSwap ( long &rX, long &rY )
  87 {
  88     Swap( rX, rY );
  89 } // LSwap
  90
  91 // -----------------------------------------------------------------------
  92
  93 // Storage free swapping using XOR
  94
  95 void ULSwap ( unsigned long &rX, unsigned long &rY )
  96 {
  97     Swap( rX, rY );
  98 } // ULSwap
  99
 100 // =======================================================================
 101
 102 // =======================================================================
 103
 104 // -----------------------------------------------------------------------
 105 //
 106 // This way of measuring distance is also called the "Manhattan distance."
 107 // Manhattan distance takes advantage of the fact that the sum of the
 108 // lengths of the three components of a 3D vector is a rough approxima-
 109 // tion of the vector's length.
 110 //
 111 // -----------------------------------------------------------------------
 112
 113 unsigned long  Euclidian2Norm ( const LRectCoorVector  pVec )
 114 {
 115     unsigned long  ndist = 0;
 116
 117     if ( pVec )
 118     {
 119         long           nDX  = 0;
 120         long           nDY  = 0;
 121         long           nDZ  = 0;
 122         unsigned long  nMax = 0;
 123         unsigned long  nMed = 0;
 124         unsigned long  nMin = 0;
 125
 126         // Find |x'-x|, |y'-y|, and |z'-z| from (x,y,z) and (x',y',z')
 127
 128         nDX = pVec[1].x - pVec[0].x;
 129         nDY = pVec[1].y - pVec[0].y;
 130         nDZ = pVec[1].z - pVec[0].z;
 131
 132         nMax = (unsigned long)abs( nDX );
 133         nMed = (unsigned long)abs( nDY );
 134         nMin = (unsigned long)abs( nDZ );
 135
 136         // Sort them (3 compares, 0-3 swaps)
 137
 138         if ( nMax < nMed )
 139         {
 140             Swap( nMax, nMed );
 141         } // if
 142
 143         if ( nMax < nMin )
 144         {
 145             Swap( nMax, nMin );
 146         } // if
 147
 148         // Approximate Euclidian distance:
 149         //
 150         //    d = max + (11/32)*med + (1/4)*min
 151         //
 152         // with +/- 8% error, where the exact formulae for d is
 153         //
 154         //  || (x',y',z') - (x,y,z) || = { |x'-x|^2 + |y'-y|^2 + |z'-z|^2 }^(1/2)
 155
 156         ndist = nMax + ( nMin >> 2UL )
 157                      + ( ( ( nMed << 3UL ) + ( nMed << 1UL ) + nMed ) >> 5UL );
 158     } // if
 159
 160     return ndist;
 161 } // RGBDistance
 162
 163 // =======================================================================
 164
 165 // =======================================================================
 166