Ferret "how to": controllong colors

[hankin@xxxxxxxxxxxxxxxxxxx (Steve Hankin)]

Ferret how-to:  exact control over colors

On Sep 13,  4:53pm, Stefan Rahmstorf, IfM Kiel 13-SEP-1995 15:41:24.61 wrote:



	> ... is there a script that produces a colour chart
	>    in r-g-b space as a test chart, to see which colours look good on
a
	> printer?



(try    yes? GO try_palette rnb2      for a quick example)


Basically there are 2 controls that effect the colors used by FILL and SHADE:
 the qualifier /PALETTE= and the qualifier /LEVELS=.

The Unix command Fpalette shows you the palettes that are available by default
(you can create others -- see Chapter 6 section 5.2 on palette files).

There are several scripts to help you control colors:

	> Fhelp palette

	try_palette [pal]    displays palette appearance for various
			     numbers of color levels
     	try_centered_palette displays centered palette appearance for
        	 	     various numbers of levels
     	exact_colors         sets up FERRET and PPLUS to modify individual
                             colors in a color palette
     	squeeze_colors       modifies a color palette by squeezing and
                             stretching the color scale

These allow you to view a given palette and to create a new one in which you
can specify the RGB value to be used for each individual color on the plot.

I hope this helps - steve





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