% 
% Draws a grid filled with hollow or filled non-overlapping squares 
% positioned at random
% Not programmed with efficiency in mind, thus it gets fairly slow for
% larger Ns.
%
% Anders Hoff February 2010

clear;
clc;
close all;
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

N = 700;   %size of grid
minSize=2; %minimum square size. 1 is not recommended

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
M=N+2; %size of matrix
rep=1000000; %break off number of repetitions
breakOff = 200; %number of unsuccessfull loops before termination
mSize=ceil(N/5); %max size of square

%create MxM matrix boreder by 3s
A = zeros(M); one=ones(1,M);
A(:,1)=one; A(:,M)=one; A(1,:)=one'; A(M,:)=one';

sizes=0;
count=0;
for a=1:1:rep
    count = count +1;
    tup = findTuple(A,N);
    x=tup(1,1);y=tup(1,2);
    size=randSqr(x,y,A,mSize);
    if size >= minSize
        A = drawSqr(x,y,size,A);
        sizes=[sizes size];
        count = 0;
    end
    if count >= breakOff
        break;
    end
end

%remove internal points
%i have a feeling there is a more efficient way of doing this
for c = 1:1:M
    for d=1:1:M
       if A(c,d) == 1;
            A(c,d)=0;
        end
    end
end

figure(1);
imshow(A,[0 3]);