How can I fill the inside circle with any color?

too long code

Answer 1

[Star Strider]

Try something like this —

imshow(imread('st1.jpg'))

a = linspace(0, 2*pi, 500).';
r = [1 2];
x = r.*cos(a);
y = r.*sin(a);

figure
hp1 = plot(x, y);
hold on
patch(hp1(1).XData, hp1(1).YData, [0.1 0.5 0.9])
hold off
axis('equal')

You will need to choose the correct (x,y) data for the inner circle. Then use the patch function to fill it.

.

[Shreen El-Sapa]

I did not send my code. When I sent it I got a meassage it is maximum.

So I cut a code from it such that the following:

a =1 ; %RADIUS

epsilon=.7;L=(1-epsilon).^(1/2);

m1=100;

r1=ones(1,m1+1)*a;

r2=ones(1,m1+1)./L;

th=[0:2*pi/m1:2*pi];

set(polar(th,r1,'-k'),'LineWidth',1.2);

set(polar(th,r2,'-k'),'LineWidth',1.2);

How can I fill this circle?

Thanks

[Star Strider]

The patch, fill, and similar functions will not work with the polar or polarplot functions (axes), and it is not possible to plot Cartesian axes over them. It will be necessary for you to create the circles as I did (in Cartesian coordinates) to fill the circle.

I do not know how you calculated the original figure, however it will be necessary to create it in Cartesian coordinates to use patch with it. One option is to use the pol2cart function to get the data from polar to Cartesian coordinates. Once you plot them in Cartesian coordinates, you can use patch.

[Shreen El-Sapa]

you saw the attached

[Star Strider]

I ran the code you posted, however it did not overplot the polar axes, so they do not appear as the circles do in my example code. (I also saw your other post, however there are so many missing variables in it that it is not possible to run it.)

If you want to use patch, you need to do everything in Cartesian coordinates. You cannot use patch with polar or polarplot.

[Shreen El-Sapa]

thanks

[Star Strider]

My pleasure!

The entire code may be too long, however saving the data that created that plot to a .mat file, and posting the code that plotted it from those data might be enough.

A less favorable option for me would be to upload the .jpg image as a .fig file instead. I may be able to work with it in that context, since I might be able to get the data from it. Some plots are relatively straightforward to work with and others can be incredibly difficult.