R RGB color

所有的颜色都是基于red, blue, green 调出来的。如果想知道你需要的颜色，在R中输入col2rgb('specific color', alpha=T)

详细说明：

It's the usual #RRGGBB color notation, w/ the last two digits   

apparently defining the amount of opacity. 

#0000FFFF is blue w/ full opacity 

To figure out how to define your color with RGB notation, use a mix of   
col2rgb and rgb functions: 

R> col2rgb('blue', alpha=T) 
       [,1] 
red      0 
green    0 
blue   255 
alpha  255 

R> rgb(red=0, green=0, blue=255, alpha=255, max=255) 
[1] "#0000FFFF" 

Play with different values of alpha (0 < alpha <= 255) in the above   
call to get different levels of opacity for your points. 

R> rgb(red=0, green=0, blue=255, alpha=10, max=255) 
[1] "#0000FF0A"