///Data structure representing RGB colors.

 ///Data structure representing RGB colors.

 ///\ingroup misc

 class Color

 {

   double _r,_g,_b;

 public:

   ///Default constructor

   Color() {}

   ///Constructor

   Color(double r,double g,double b) :_r(r),_g(g),_b(b) {};

   ///Returns the red component

   double & red() {return _r;}

   ///Returns the red component

   const double & red() const {return _r;}

   ///Returns the green component

   double & green() {return _g;}

   ///Returns the green component

   const double & green() const {return _g;}

   ///Returns the blue component

   double & blue() {return _b;}

   ///Returns the blue component

   const double & blue() const {return _b;}

   ///Set the color components

   void set(double r,double g,double b) { _r=r;_g=g;_b=b; };

 };

 ///Maps <tt>int</tt>s to different \ref Color "Color"s

 ///This map assigns one of the predefined \ref Color "Color"s

 ///to each <tt>int</tt>. It is possible to change the colors as well as their

 ///number. The integer range is cyclically mapped to the provided set of colors.

 ///

 ///This is a true \ref concept::ReferenceMap "reference map", so you can also

 ///change the actual colors.

 class ColorSet : public MapBase<int,Color>

 {

   std::vector<Color> colors;

 public:

   ///Constructor

   ///Constructor

   ///\param have_white indicates whether white is

   ///amongst the provided color (\c true) or not (\c false). If it is true,

   ///white will be assigned to \c 0.

   ///\param num the number of the allocated colors. If it is \c 0

   ///the default color configuration is set up (26 color plus the while).

   ///If \c num is less then 26/27 then the default color list is cut. Otherwise

   ///the color list is filled repeatedly with the default color list.

   ///(The colors can be changed later on.)

   ColorSet(bool have_white=false,int num=0)

   {

     do {

       if(have_white) colors.push_back(Color(1,1,1));

       colors.push_back(Color(0,0,0));

       colors.push_back(Color(1,0,0));

       colors.push_back(Color(0,1,0));

       colors.push_back(Color(0,0,1));

       colors.push_back(Color(1,1,0));

       colors.push_back(Color(1,0,1));

       colors.push_back(Color(0,1,1));

       colors.push_back(Color(.5,0,0));

       colors.push_back(Color(0,.5,0));

       colors.push_back(Color(0,0,.5));

       colors.push_back(Color(.5,.5,0));

       colors.push_back(Color(.5,0,.5));

       colors.push_back(Color(0,.5,.5));

       colors.push_back(Color(.5,.5,.5));

       colors.push_back(Color(1,.5,.5));

       colors.push_back(Color(.5,1,.5));

       colors.push_back(Color(.5,.5,1));

       colors.push_back(Color(1,1,.5));

       colors.push_back(Color(1,.5,1));

       colors.push_back(Color(.5,1,1));

       colors.push_back(Color(1,.5,0));

       colors.push_back(Color(.5,1,0));

       colors.push_back(Color(1,0,.5));

       colors.push_back(Color(0,1,.5));

       colors.push_back(Color(0,.5,1));

       colors.push_back(Color(.5,0,1));

     } while(int(colors.size())<num);

     //    colors.push_back(Color(1,1,1));

     if(num>0) colors.resize(num);

   }

   ///\e

   Color &operator[](int i)

   {

     return colors[i%colors.size()];

   }

   ///\e

   const Color &operator[](int i) const

   {

     return colors[i%colors.size()];

   }

   ///\e

   void set(int i,const Color &c)

   {

     colors[i%colors.size()]=c;

   }

   ///Sets the number of the exiting colors.

   void resize(int s) { colors.resize(s);}

   ///Returns the number of the existing colors.

   std::size_t size() const { return colors.size();}

 };

 ///Returns a visible distinct \ref Color

 ///Returns a \ref Color which is as different from the given parameter

 ///as it is possible.

 inline Color distantColor(const Color &c) 

 {

   return Color(c.red()<.5?1:0,c.green()<.5?1:0,c.blue()<.5?1:0);

 }

 ///Returns black for light colors and white for the dark ones.

 ///Returns black for light colors and white for the dark ones.

 inline Color distantBW(const Color &c){

   double v=(.2125*c.red()+.7154*c.green()+.0721*c.blue())<.5?1:0;

   return Color(v,v,v);

 }