src/frontends/xforms/Color.C

   1 /* This file is part of
   2  * ======================================================
   3  *
   4  *           LyX, The Document Processor
   5  *
   6  *          Copyright 1995 Matthias Ettrich
   7  *          Copyright 1995-2001 The LyX Team.
   8  *
   9  *======================================================*/
  10
  11 #include <config.h>
  12
  13 #include <algorithm> // max
  14 #include <cmath> // floor
  15
  16 #include FORMS_H_LOCATION
  17
  18 #ifdef __GNUG_
  19 #pragma implementation
  20 #endif
  21
  22 #include "Color.h"
  23
  24 using std::max;
  25 using std::min;
  26
  27 namespace {
  28
  29 int const nohue = -1;
  30
  31 } // namespace anon
  32
  33 RGBColor::RGBColor(HSVColor const & hsv)
  34 {
  35         double h = hsv.h;
  36         double const s = hsv.s;
  37         double const v = hsv.v;
  38
  39         double rd, gd, bd;
  40
  41         if (h == nohue || s == 0.0) {
  42                 rd = gd = bd = v;
  43         } else {
  44                 if (h == 360.0) h = 0.0;
  45                 h /= 60.0;
  46
  47                 int const j = max(0, static_cast<int>(::floor(h)));
  48                 //if (j < 0) j = 0;
  49
  50                 double const f = h - j;
  51                 double const p = v * (1.0 - s);
  52                 double const q = v * (1.0 - (s * f));
  53                 double const t = v * (1.0 - (s * (1.0 - f)));
  54
  55                 switch (j) {
  56                 case 0:
  57                         rd = v;
  58                         gd = t;
  59                         bd = p;
  60                         break;
  61                 case 1:
  62                         rd = q;
  63                         gd = v;
  64                         bd = p;
  65                         break;
  66                 case 2:
  67                         rd = p;
  68                         gd = v;
  69                         bd = t;
  70                         break;
  71                 case 3:
  72                         rd = p;
  73                         gd = q;
  74                         bd = v;
  75                         break;
  76                 case 4:
  77                         rd = t;
  78                         gd = p;
  79                         bd = v;
  80                         break;
  81                 case 5:
  82                         rd = v;
  83                         gd = p;
  84                         bd = q;
  85                         break;
  86                 default:
  87                         rd = v;
  88                         gd = t;
  89                         bd = p;
  90                         break;  // should never happen.
  91                 }
  92         }
  93
  94         r = static_cast<int>(::floor((rd * 255.0) + 0.5));
  95         g = static_cast<int>(::floor((gd * 255.0) + 0.5));
  96         b = static_cast<int>(::floor((bd * 255.0) + 0.5));
  97 }
  98
  99
 100 HSVColor::HSVColor(RGBColor const & rgb)
 101 {
 102         double const r = rgb.r / 255.0;
 103         double const g = rgb.g / 255.0;
 104         double const b = rgb.b / 255.0;
 105
 106         double const maxval = max( max( r, g), b);
 107         double const minval = min( min( r, g), b);
 108
 109         v = maxval;
 110
 111         double const diff = maxval - minval;
 112         if (maxval != 0.0)
 113                 s = diff / maxval;
 114         else
 115                 s = 0.0;
 116
 117         h = nohue;
 118         if (s != 0.0) {
 119                 double const rc = (maxval - r) / diff;
 120                 double const gc = (maxval - g) / diff;
 121                 double const bc = (maxval - b) / diff;
 122
 123                 if (r == maxval)
 124                         h = bc - gc;
 125                 else if (g == maxval)
 126                         h = 2.0 + rc - bc;
 127                 else if (b == maxval)
 128                         h = 4.0 + gc - rc;
 129
 130                 h *= 60.0;
 131                 if (h < 0)
 132                         h += 360;
 133         }
 134 }