[alt.graphics.pixutils] Colour Spectrum.

ee9jan@gdt.bath.ac.uk (J A Nicholls) (05/02/91)

	Does anybody know of any equations that will approximate to a colour
spectrum ? I am trying to generate a simulated spectrum based on temperature,
ie 0 degrees = Blue, 100 degrees = red with the intermediate temperatures
being shown by the appropriate colour of the spectrum.

	The format is in 24 bit raw bitmap so I need an equation for each of
the RGB components. At the moment I am using the following equations :-

	R = (char)(temp>=50.0 ? 255.0*(temp/50-1) : 0)

	G = (char)(temp<=50.0 ? 255.0*(temp/50) : 255.0*(2-temp/50))

	B = (char)(temp<=50.0 ? 255.0*(1-temp/50) : 0)

to calculate a value for each colour from 0 to 255. This does produce a
'spectrum' but it looks very false also it doesn't seem to develop the
secondary colours at all well.

Any help appreciated. Jez.

-- 
Jez Nicholls               
<ee9jan@gdt.bath.ac.uk>
                             "Marmalade, I like marmalade.", "Ooh me flakes."
#include "disclaimer.h"      These quotes courtesy of Alan. (APB AHM PF 1971)