MATLAB: How to fill a rectangle (or circle) in a matrix

circlecoordinatesfillpolygonrectangle

Imagine the following matrix.
     1     1     1     1     1     1     1     1     1     1
     1     1    10    10    10    10    10     1     1     1
     1     1    10     1     1     1    10     1     1     1
     1     1    10     1     1     1    10     1     1     1
     1     1    10     1     1     1    10     1     1     1
     1     1    10    10    10    10    10     1     1     1
     1     1     1     1     1     1     1     1     1     1
     1     1     1     1     1     1     1     1     1     1
     1     1     1     1     1     1     1     1     1     1
I know the coordinates of the 10's. they are stored in A and B. How do I use the known coordinates of 10's to fill in the 1's within the square of 10's? thanx for help.
I have simplified my problem here. I have extracted the essence of the problem above. But for those interested I'll explain the following. I want to create a filled circle inside a bigger matrix. Since I have the coordinates of the outer circle, I need a way to fill in the inside. My code:
k=zeros(300,300)+200
for theta=0:.001:7;
  radius=10
  [X,Y] = pol2cart(theta,radius);
  A=[round(X)+radius];
  B=[round(Y)+radius];
  ring = sub2ind(size(K),A,B);
  kleur=90;
  K(A,B) = kleur;
end

Best Answer

Here's one way to fill the space between the top row of 10s and the bottom row of 10s:
K=  [1     1     1     1     1     1     1     1     1     1
     1     1    10    10    10    10    10     1     1     1
     1     1    10     1     1     1    10     1     1     1
     1     1    10     1     1     1    10     1     1     1
     1     1    10     1     1     1    10     1     1     1
     1     1    10    10    10    10    10     1     1     1
     1     1     1     1     1     1     1     1     1     1
     1     1     1     1     1     1     1     1     1     1
     1     1     1     1     1     1     1     1     1     1]; 
for cols = 1:size(K,2); 
   K(find(K(:,cols)==10,1,'first'):find(K(:,cols)==10,1,'last'),cols) = 10; 
end
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