generate coordinates circle,square,rectangle

Hello,

I have to generate points(matrix),so that i have view the points as a circle(square,rectagle), when i display points(matrix) through plot.

Could someone help me?

Thanks.

Answer 1

[Image Analyst]

For circle and ellipse, see the FAQ for code examples: http://matlab.wikia.com/wiki/FAQ?title=FAQ&cb=7341#How_do_I_create_a_circle.3F

For a square or rectangle, if you have x1, x2, y1, and y2, you can make it with plot by making coordinates of the box and calling plot

xBox = [x1 x2 x2 x1 x1];
yBox = [y1 y1 y2 y2 y1];
plot(xBox, yBox, 'r-', 'LineWidth', 2);

Of course that can ge generalized to any polygon, just list all the vertices.

Answer 2

[Giorgos Papakonstantinou]

% circle
r=1; % radius
C=[1 1];
theta=0:2*pi/360:2*pi; % the angle

m=r*[cos(theta')+C(1) sin(theta')+C(2)]; % the points you asked
plot(m(:,1), m(:,2))
axis equal
hold all
% Rectangle
a=1; % side a
b=.5; % side b
s=[0.5 0.75]; % bottom left start point
A=[s(1) s(1)+a s(1)+a s(1) s(1);s(2) s(2) s(2)+b s(2)+b s(2)];
plot(A(1,:), A(2,:))
axis equal

[Will Reeves]

nice... although the "r*" shouldn't apply to the centre coordinate offset:

m=r*[cos(theta') sin(theta')] + C; % the points you asked

instead of this:

m=r*[cos(theta')+C(1) sin(theta')+C(2)]; % the points you asked

Or am I being silly?!