rwbmap.m

function rwb = rwbmap(ncolors);
%function rwb = rwbmap(ncolors);
%	Returns a colormap going from Red to White to Blue using ncolors.

if nargin<1
	ncolors=256;
end
ncolors = 2*floor(ncolors/2);

nmax = ncolors/2 - 1;
r = [repmat(nmax,1,ncolors/2),nmax:-1:0]/nmax;
g = [0:nmax,nmax:-1:0]/nmax;
b = [0:nmax,repmat(nmax,1,ncolors/2)]/nmax;

rwb = [r;g;b]';