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// $Id: G4Colour.hh,v 1.9 2003/09/18 11:03:11 johna Exp $
// GEANT4 tag $Name: geant4-06-00-patch-01 $
//
// 
// John Allison 20th October 1996

// Class Description:
// Class G4Colour has 4 fields, which represent the RGBA (red, green, blue, 
// and alpha) components of colour. Each component takes a value between 
// 0 and 1. If an irrelevant value, i.e., a value less than 0 or greater 
// than 1, is given as an argument of the constructor, such a value is 
// automatically clipped to 0 or 1. Alpha is opacity (1 = opaque).
// 
// A G4Colour object is instantiated by giving red, green, and blue 
// components to its constructor, i.e., 
// 
//      G4Colour::G4Colour ( G4double r = 1.0, 
//                           G4double g = 1.0, 
//                           G4double b = 1.0, 
//                           G4double a = 1.0);
//                                   // 0<=red, green, blue <= 1.0 
// 
// The default value of each component is 1.0. That is to say, the default 
// colour is "white".  For example, colours which are often used can be 
// instantiated as follows: 
// 
//      G4Colour  white   ()              ;  // white
//      G4Colour  white   (1.0, 1.0, 1.0) ;  // white
//      G4Colour  gray    (0.5, 0.5, 0.5) ;  // gray
//      G4Colour  black   (0.0, 0.0, 0.0) ;  // black
//      G4Colour  red     (1.0, 0.0, 0.0) ;  // red
//      G4Colour  green   (0.0, 1.0, 0.0) ;  // green
//      G4Colour  blue    (0.0, 0.0, 1.0) ;  // blue
//      G4Colour  cyan    (0.0, 1.0, 1.0) ;  // cyan
//      G4Colour  magenta (1.0, 0.0, 1.0) ;  // magenta 
//      G4Colour  yellow  (1.0, 1.0, 0.0) ;  // yellow
// 
// After instantiation of a G4Colour object, you can access to its components 
// with the following access functions: 
// 
//      G4double G4Colour::GetRed   () const ; // Get the red   component. 
//      G4double G4Colour::GetGreen () const ; // Get the green component.
//      G4double G4Colour::GetBlue  () const ; // Get the blue  component.
//
// Class Description - End:

#ifndef G4COLOUR_HH
#define G4COLOUR_HH

#include "globals.hh"
#include "G4ThreeVector.hh"
#include <iostream>

class G4Colour {
  friend std::ostream& operator << (std::ostream& os, const G4Colour& c);

public: // With description

  G4Colour (G4double r = 1., G4double g = 1., G4double b = 1.,
	    G4double a = 1.);
  G4Colour (G4ThreeVector);
  // Converts the components of the 3-vector into red, green, blue.
  // The opacity, alpha = 1.
  operator G4ThreeVector();
  // Converts red, green, blue into the components of a 3-vector.
  G4bool operator != (const G4Colour& c) const;
  G4double GetRed   () const;
  G4double GetGreen () const;
  G4double GetBlue  () const;
  G4double GetAlpha () const;  // alpha = opacity = 1. - transparency.
private:
  G4double red, green, blue, alpha;
};

inline G4double G4Colour::GetRed   () const {return red;}
inline G4double G4Colour::GetGreen () const {return green;}
inline G4double G4Colour::GetBlue  () const {return blue;}
inline G4double G4Colour::GetAlpha () const {return alpha;}

#endif