Patch color error "Vectors must be the same length."

I am trying to plot 2 patchs with different color. " patch(x, y, c, 'FaceColor', 'flat');" shows error "Vectors must be the same length.". How to setup the color?

x =[ 1     2
     1     2
     2     3
     2     3];
 
y =[1     2
    2     3
    2     3
    1     2];
 
c=[0    0.7344
   0    1.0000
   0.5156    0.2656];
 
figure;
patch(x, y, 'r');
figure;
patch(x, y, c, 'FaceColor', 'flat');

Thanks,

cfy30

[Geoff Hayes]

cfy30 - which of the effects from C - polygon colours are you interested in? Because that will tell you what the dimensions for C should be.

[cfy30]

Hi Geoff,

I want to set the face color of the patch by the RGB color. Any easy way to do so?

Thanks,

cfy30

Answer 1

[Tommy]

The docs linked by Geoff mention that you can specify an n-by-1-by-3 array of RGB values (for n number of faces). I've defined c to be an n-by-3 array of RGB values and then used reshape() to get the dimensions right:

c=[0    0   0.5156           % <- RGB of first color
   0.7344   1.0000  0.2656]; % <- RGB of second color

figure;
patch(x, y, reshape(c,[],1,3), 'FaceColor', 'flat');

[cfy30]

Thanks Tommy! It works!

Answer 2

[Ameer Hamza]

Using for-loop seems to be the simplest solution in this case.

x =[ 1     2
     1     2
     2     3
     2     3];
 
y =[1     2
    2     3
    2     3
    1     2];
 
c=[0    0.7344
   0    1.0000
   0.5156    0.2656];


figure;
for i=1:size(x,2)
    patch(x(:,i), y(:,i), c(:,i).');
end

[cfy30]

Thanks Ameer. I used for-loop but want to experiment without it. When I plot up to like 1000 patchs, copy and paste the figure in emf formatting to Word/Powerpoint becomes very big. I want to see if the issue is because of the for-loop used.