// FILE: color.h
// written for the course 2172, 1999
//
#if !defined(_COLOR_H_)
#define _COLOR_H_

#include <iostream.h>


/* color: <red,green,blue>
 *
 * the color <-1,-1,-1> represents
 * "clear", "transparent" or "the eraser"
 *
 * <0,0,0>       :   black
 * <255,255,255> : white
 */
class color {

  protected:
    short _red,_green,_blue; // color components
                             // according to rgb
                             // scheme
  public:
    // color(r,g,b)
    // creates a color with specified comp
    color(short=0,short=0,short=0);
     
    short red() const;   // red component
    short green() const; // green component
    short blue() const;  // blue component
     
  // returns true if c1 == c2
  friend bool operator==(const color&,const color&);
  // returns true if c1 != c2
  friend bool operator!=(const color&,const color&);

  friend ostream& operator<<(ostream&, const color&);
};

extern const color clear; // the color <-1,-1,-1>

// some standard colors
extern const color black;
extern const color white;
extern const color red;
extern const color green;
extern const color blue;
extern const color yellow;
extern const color magenta;
extern const color cyan;

#endif