# How to get sub-circles from orignal circle

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Mekala balaji on 22 Mar 2019
Answered: Image Analyst on 24 Mar 2019
Hi,
I have circle with diameter 1, I use below code:
meshgrid(x,y)
Fig,surf(x,y,z,'facecolor','interp','edgecolor',none);view(2)
xlim([0 1]),ylim([0 1))
colorbar;colormap(hot);
Now I want plot a circle
figure2. Keep original circle diameter 0-0.39 from bottom as it is, and fill rest of the original area with black color
Figure3: Keep original circle diameter 0.39~1 (up or top) as it is, and fill rest of the original area with black color
Figure4: Keep original circle diameter 0~63 from left as it is, and fill rest of the original area with black color
Figure5: Keep original circel diameter 0.4~1 to right as it is,and fill rest of the original area with black color
Kindly some help to do this.
Mekala balaji on 24 Mar 2019
N = 256;
c = colormap(jet(N));
th = linspace(0, 2*pi, N);
r = 0:0.5:1;
[TH,R] = meshgrid(th,r);
[X,Y] = pol2cart(TH,R);
C = bsxfun(@times,(X + Y),th);
figure(1)
surf(X,Y,C)
view([0 90])
axis square
grid off
I want keep the circle as it is as above in 0.39~0.6 diameter range, and fill rest of the area in black color

Image Analyst on 24 Mar 2019
See this color wheel example. Adapt as needed.

R2016a

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