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 )

x=input('Size: ') X=triu(ones(x),1) imshow(X)

[Kenneth Phang]

Is there anyway for me to make a matrix to this?

1 1 1 1 1 1 1 0 1 1 1 1 1 1 1
1 1 1 1 1 1 0 0 0 1 1 1 1 1 1
1 1 1 1 1 0 0 0 0 0 1 1 1 1 1
1 1 1 1 0 0 0 0 0 0 0 1 1 1 1
1 1 1 0 0 0 0 0 0 0 0 0 1 1 1
1 1 0 0 0 0 0 0 0 0 0 0 0 1 1
1 0 0 0 0 0 0 0 0 0 0 0 0 0 1
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

[Matthew Eicholtz]

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);

Answer 1

[Matthew Eicholtz]

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]

It helps a lot with that code, i know how to basically start with it, thanks!