How to draw a square with specific plot points

I'm trying to create two squares, one larger one, and the other within it.

I attempted to create one using matrices. I create one with x = [0 0 1 1] and y = [0 1 1 0]

I wanted a line to connect each one of the points, to thus create a line. However, when I did that, I only received three lines connect between the dots for some reason. The bottom points (0,0) and (1,0) for some reason were not connected. I then attempted to make a second square, and the same thing happened, with the two lower points in regards to their Y points did not connect. I tried using the rectangle function as well, but can't get a square within a square to appear. Any help would be great. Thanks

Answer 1

[Image Analyst]

You need 5 points - the last one is to "close off" the square, otherwise it won't be closed because you didn't draw the line back to the starting point. So, try this

% Draw first, outer rectangle.
x1=0;
x2=1;
y1=0;
y2=1;
x = [x1, x2, x2, x1, x1];
y = [y1, y1, y2, y2, y1];
plot(x, y, 'b-', 'LineWidth', 3);
hold on;

% Draw the second, inner rectangle.
x1=0.25;
x2=.75;
y1=0.25;
y2=.75;
x = [x1, x2, x2, x1, x1];
y = [y1, y1, y2, y2, y1];
plot(x, y, 'r-', 'LineWidth', 3);

% Define the plot region outer limits of the axes.
xlim([-0.5, 1.5]);
ylim([-0.5, 1.5]);
grid on;
axis equal % Make sure the aspect ratio is correct so that they look like squares.

[Paul]

perfect!

If you ever had to create two similar objects like this (for example two squares), would you recommend going about it another way? I tried with the rectangle function as well, it seemed potentially more convenient.

Once again, thanks for the response.

[Image Analyst]

I think the way I did it is easier to understand than rectangle. In my mind I just visualize starting at the upper left corner and marching around the square in a clockwise fashion. First I do the x's then I do the y's. And so it's really quick for me to construct the 5 element x and y matrices.

Answer 2

[Camilo Malagon Nieto]

Worth to say that there is a function now to make a rectangle and smooth the corners.

https://in.mathworks.com/help/matlab/ref/rectangle.html

Cheers,

[Tamar Hoory]

thanks for the useful answer!

Answer 3

[Steven Lord]

Depending on what you want to do with those shapes, creating a polyshape array may be useful.

 x = [0 0 1 1];
 y = [0 1 1 0];
 P1 = polyshape(x, y);
 plot(P1)
 axis square

 P2 = translate(scale(P1, 0.5), [0.25 0.25]);
 figure
 plot([P1, P2])
 axis square

Answer 4

[NAGENDRA KUMAR]

Please write this code

x = [0 0 1 1 0]; 
y = [0 1 1 0 0]; 
plot(x,y,'r', 'LineWidth',3)

Answer 5

[Pranav]

The IMAGE ANALYST did a great job at answering this question.

[Image Analyst]

Thanks! 🙂

[Pranav]

Anytime, Keep up the great work!!!