# How to write a Matlab script that is able to output images of triangles based on the size input? The following shows the half of a triangle but i can't find a way to make an isolated triangle. (The size you can put at range 3 - 8 )

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Kenneth Phang on 5 Oct 2016
Commented: Kenneth Phang on 6 Oct 2016
x=input('Size: ') X=triu(ones(x),1) imshow(X)
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Matthew Eicholtz on 5 Oct 2016
See the second option in my answer below (insertShape). More specifically for the matrix above, use:
x = ones(8,15);
x = insertShape(x,'filledpolygon',[1 8 8 1 15 8],'Color','black','Opacity',1);
x = (x(:,:,1)==1);

Matthew Eicholtz on 5 Oct 2016
Edited: Matthew Eicholtz on 5 Oct 2016
What types of triangles do you need? And what will they be used for?
If you need very basic triangles, you could use the triangular marker types for scatter plots:
[y,x] = meshgrid(1:4);
z = 250:200:1000; %size of markers
figure;
axis([0 5 0 5]);
hold on;
scatter(x(1,:),y(1,:),z,'r^','FaceColor','r');
scatter(x(2,:),y(2,:),z,'gv','FaceColor','g');
scatter(x(3,:),y(3,:),z,'b<','FaceColor','b');
scatter(x(4,:),y(4,:),z,'m>','FaceColor','m');
hold off;
Or, if you need to create triangles with more variation in size, shape, and vertex position, try using insertShape:
figure;
I = zeros(100,'uint8');
J = insertShape(I,'filledpolygon',randi([10 90],1,6),'Color','white','Opacity',1);
imshow(J);
Note that this option actually embeds the triangle in an image. If you want to have a triangle "object", try using patch:
figure;
x = randi([0 10],1,3); %random x-coordinates
y = randi([0 10],1,3); %random y-coordinates
patch(x,y,'green');
Kenneth Phang on 6 Oct 2016
It helps a lot with that code, i know how to basically start with it, thanks!

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