A color is represented by a CLX color object, in which each of the red,
      green, and blue values is specified by an
      rgb-val
      -- a floating point number between 0.0 and 1.0. (see
      paragrpah
      1.6, Data Types). The value 0.0
      represents the minimum intensity, while 1.0 represents the maximum
      intensity. CLX automatically converts
      rgb-val
      values into 16-bit integers when sending colors to an X server. The X
      server, in turn, scales 16-bit color values to match the actual
      intensity range supported by the screen. 
    
      Colors used on :gray-scale screens must have the same value for
      each of red, green, and blue. Only one of these values is used by screen
      hardware to determine intensity; however, CLX does not define which of
      red, green, or blue is actually used. 
    
      The following paragraphs describe the CLX functions used to create,
      access, and modify colors. 
    
      
      
      
      
        
          
          
          
        
          | make-color | &key
            (:blue 1.0) (:green 1.0)
            (:red 1.0) &allow-other-keys | Function | 
      
      
        
          |  | 
              
                :blue, :green, :red 
              
                rgb-val
                values that specify the saturation for each primary.
             
              Creates, initializes, and returns a new
              color
              object with the specified values for red, green, and blue. 
             
              
                color 
              
                Type
                color. 
             | 
      
     
     
    
      
      
      
      
        
          
          
          
        
          | color-blue | color | Function | 
      
      
        
          |  | 
              
                color 
              
                A
                color object.
             
              Returns and (with setf) sets the value for blue in the
              color. 
             
              
                blue-intensity 
              
                Type
                rgb-val. 
             | 
      
     
     
    
      
      
      
      
        
          
          
          
        
          | color-green | color | Function | 
      
      
        
          |  | 
              
                color 
              
                A
                color object.
             
              Returns and (with setf) sets the value for green in the
              color. 
             
              
                green-intensity 
              
                Type
                rgb-val. 
             | 
      
     
     
    
      
      
      
      
      
        
          |  | 
              Returns non-nil if the argument is a
              color
              object and nil otherwise.
             
              
                color-p 
              
                Type
                boolean. 
             | 
      
     
     
    
      
      
      
      
      
        
          |  | 
              
                color 
              
                A
                color object.
             
              Returns and (with setf) sets the value for red in the
              color. 
             
              
                red-intensity 
              
                Type
                rgb-val. 
             | 
      
     
     
    
      
      
      
      
      
        
          |  | 
              
                color 
              
                A
                color object.
             
              Returns the values for red, green, and blue in the color. 
             
              
                red, green, blue 
              
                Type
                rgb-val. 
             |