How can i create random rectangles (automatically)?

I want to create many rectangles. This should be done automatically. How can i do this without typing thousands of values in my code? Is there an solution?

• In my code i wrote every single coordinate point (4 points of each rectangle) manually in my vector "V".
• Also how to connect them. "F"
• And the value of each rectangle. "C"

Thank you for your input/help. I really appreciate it.

clc
clear all
figure;
V = [0,0;1,0;1,1;0,1;5,5;10,5;10,10;5,10;2,2;4,2;4,4;2,4];
F = [1,2,3,4;5,6,7,8;9,10,11,12];%Dieser Vektor sagt mir in welcher Reihenfolge die Punkte
C = [50;24;99]; 
patch('Faces',F,'Vertices',V,'FaceVertexCData',C,'FaceColor','flat','EdgeColor','none') %Befehl fürs "zeichnen"
colormap(parula)
colorbar

Answer 1

[Guillaume]

This will create as many rectangles as you want in any range you want:

numrects = 100;         %choose your own value
minx = -10; maxx = 10;  %choose your own values
miny = -5; maxy = 8;    %choose your own values

rectpos = rand(numrects, 4) .* repmat([maxx - minx, maxy - miny], numrects, 2) + repmat([minx, miny], numrects, 2);  %get random corner coordinates
rectpos = [min(rectpos(:, [1, 2]), rectpos(:, [3, 4])), abs(rectpos(:, [3, 4]) - rectpos(:, [1, 2]))];  %transform in [x, y, width, height]
rectcolour = rand(numrects, 3);
figure;
for row = 1:numrects
    rectangle('Position', rectpos(row, :), 'EdgeColor', rectcolour(row, :));
end
xlim([minx, maxx]);
ylim([miny, maxy]);

[Philipp Mueller]

ok it works thank you and how can i combine it with my code.... sorry i am really bad in matlab

[Guillaume]

Not knowing what your code is, I assume you just need to copy/paste the above, and change the inputs (first three lines) to what you want.

Answer 2

[Adam]

Using

doc rectangle

would be simpler than defining a patch like that I would think. Then if you want random positions it is just a case of creating random numbers and because you are defining a top left location and height, width you will always have a rectangle rather than using patch with random numbers.

[Philipp Mueller]

@adam ... sorry i can understand you cause my english is not the best and i am new in matlab. what do you mean? how should i modify my code?

i just want to test my code with many rectangles.

[KSSV]

Adam wants to say...you read the command named rectangle in matlab.

Type help rectangle

[Guillaume]

@Siva, as per Adam's post

doc rectangle

instead of help rectange. You get nicer documentation.

Answer 3

[KSSV]

clc; clear all
for i = 1:10
    ver = RandRect(rand(1,2),rand(1,2)) ;
    patch(ver(:,1),ver(:,2),'r')
    hold on
end

function vertices = RandRect(P1,P3)
x1 = P1(1) ; y1 = P1(2) ;
x2 = P3(1) ; y2 = P3(2) ;
L = x2-x1 ; 
B = y2-y1 ;
P2 = [x1+L y1] ;
P4 = [x1 y1+B] ;
vertices = [P1 ; P2; P3; P4] ;

[Philipp Mueller]

@dr. siva, thank you for your help. I think its a stupid question but you know i have just worked some hours with matlab. I saw this function from you creates rectangles but how can i combine your part with my code part so that it works. I want to have these colorful rectangles in my plot. so sorry for this question

[KSSV]

Copy the lines:

for i = 1:10
    ver = RandRect(rand(1,2),rand(1,2)) ;
    patch(ver(:,1),ver(:,2),'r')
    hold on
end

where you want to use in your code. and keep the function RandRect.m in the same folder.