# Concentric circles with different colors

32 views (last 30 days)
Siddhartha on 13 Feb 2018
Answered: Jos (10584) on 16 Feb 2018
I'm trying to make concentric circles that have different edge colors like this:
I have made the concentric circles but I only can do it with one unified edge colors for all the circles. How do I specify each one with a different color?
Here is my code so far:
for
i=30:-5:5
rectangle('Position',[-i,-i,2*i,2*i],'Curvature',[1 1],...
'EdgeColor','y', 'LineWidth',4)
end
Thanks!

Gayatri Menon on 16 Feb 2018
Hi,
Instead of using color option for specifying the color, you could use RGB triplets to specify them.You could use rand command to generate random values for RGB triplets in each iteration
rectangle('Position',[-i,-i,2*i,2*i],'Curvature',[1 1],'EdgeColor',rand(1,3), 'LineWidth',4)
Hope the above helps
Thanks

Jos (10584) on 16 Feb 2018
You can specify a colormap beforehand:
R = 30:-5:5 ; % radii
N = numel(R) ; %
Cmap = parula(N) ; % one of the many available maps, see the help
% now loop over the radii and colormaps using indexing
for k = 1:N
pos = R(k) * [-1 -1 2 2] ; % position
clr = Cmap(k,:) ; % RGB triplet
rectangle('Position', pos, 'Curvature', [1 1], ...
'EdgeColor',clr, 'LineWidth', 4)
end