src/frontends/xforms/Color.C

   1 /**
   2  * \file Color.C
   3  * This file is part of LyX, the document processor.
   4  * Licence details can be found in the file COPYING.
   5  *
   6  * \author Angus Leeming
   7  *
   8  * Full author contact details are available in file CREDITS
   9  */
  10
  11 #include <config.h>
  12
  13 #ifdef __GNUG__
  14 #pragma implementation
  15 #endif
  16
  17 #include "Color.h"
  18 #include <algorithm> // max
  19 #include <cmath> // floor
  20 #include FORMS_H_LOCATION
  21
  22 #ifndef CXX_GLOBAL_CSTD
  23 using std::floor;
  24 #endif
  25
  26 using std::max;
  27 using std::min;
  28
  29 namespace {
  30
  31 int const nohue = -1;
  32
  33 } // namespace anon
  34
  35 RGBColor::RGBColor(HSVColor const & hsv)
  36 {
  37         double h = hsv.h;
  38         double const s = hsv.s;
  39         double const v = hsv.v;
  40
  41         double rd, gd, bd;
  42
  43         if (h == nohue || s == 0.0) {
  44                 rd = gd = bd = v;
  45         } else {
  46                 if (h == 360.0) h = 0.0;
  47                 h /= 60.0;
  48
  49                 int const j = max(0, static_cast<int>(::floor(h)));
  50                 //if (j < 0) j = 0;
  51
  52                 double const f = h - j;
  53                 double const p = v * (1.0 - s);
  54                 double const q = v * (1.0 - (s * f));
  55                 double const t = v * (1.0 - (s * (1.0 - f)));
  56
  57                 switch (j) {
  58                 case 0:
  59                         rd = v;
  60                         gd = t;
  61                         bd = p;
  62                         break;
  63                 case 1:
  64                         rd = q;
  65                         gd = v;
  66                         bd = p;
  67                         break;
  68                 case 2:
  69                         rd = p;
  70                         gd = v;
  71                         bd = t;
  72                         break;
  73                 case 3:
  74                         rd = p;
  75                         gd = q;
  76                         bd = v;
  77                         break;
  78                 case 4:
  79                         rd = t;
  80                         gd = p;
  81                         bd = v;
  82                         break;
  83                 case 5:
  84                         rd = v;
  85                         gd = p;
  86                         bd = q;
  87                         break;
  88                 default:
  89                         rd = v;
  90                         gd = t;
  91                         bd = p;
  92                         break;  // should never happen.
  93                 }
  94         }
  95
  96         r = static_cast<int>(::floor((rd * 255.0) + 0.5));
  97         g = static_cast<int>(::floor((gd * 255.0) + 0.5));
  98         b = static_cast<int>(::floor((bd * 255.0) + 0.5));
  99 }
 100
 101
 102 HSVColor::HSVColor(RGBColor const & rgb)
 103 {
 104         double const r = rgb.r / 255.0;
 105         double const g = rgb.g / 255.0;
 106         double const b = rgb.b / 255.0;
 107
 108         double const maxval = max(max(r, g), b);
 109         double const minval = min(min(r, g), b);
 110
 111         v = maxval;
 112
 113         double const diff = maxval - minval;
 114         if (maxval != 0.0)
 115                 s = diff / maxval;
 116         else
 117                 s = 0.0;
 118
 119         h = nohue;
 120         if (s != 0.0) {
 121                 double const rc = (maxval - r) / diff;
 122                 double const gc = (maxval - g) / diff;
 123                 double const bc = (maxval - b) / diff;
 124
 125                 if (r == maxval)
 126                         h = bc - gc;
 127                 else if (g == maxval)
 128                         h = 2.0 + rc - bc;
 129                 else if (b == maxval)
 130                         h = 4.0 + gc - rc;
 131
 132                 h *= 60.0;
 133                 if (h < 0)
 134                         h += 360;
 135         }
 136 }