calc_width_ngon.m

function W = calc_width_ngon(a,b)
if length(a) == length(b) && length(a) >= 2
    % SIDES
    v = zeros(length(a)+1,1);
    v(1) = abs(a(1)+1i*b(1));
    for i = 2:length(a)
        v(i) = abs((a(i)-a(i-1))+1i*(b(i)-b(i-1)));
    end
    v(length(a)+1) = abs(a(length(a))+1i*b(length(a)));
    % HEIGHTS
    h = zeros(length(a)+1,1);
    % h1
    j = 1;
    while j <= length(a)
        h1 = abs(a(j)*(b(1)-b(j))-b(j)*(a(1)-a(j)))/v(1);
        if h1 > h(1)
            h(1) = h1;
        end
        j = j+1;
    end
    % hi
    for i = 2:length(a)
        h(i) = abs(a(i-1)*b(i)-b(i-1)*a(i))/v(i);
        j = 1;
        while j <= length(a)
            hi = abs((a(i-1)-a(j))*(b(i)-b(j))-(b(i-1)-b(j))*(a(i)-a(j)))/v(i);
            if hi > h(i)
                h(i) = hi;
            end
            j = j+1;
        end
    end
    % hn
    j = 1;
    while j <= length(a)
        hn = abs((a(length(a))-a(j))*b(j)-(b(length(a))-b(j))*a(j))/v(length(a)+1);
        if hn > h(length(a)+1)
            h(length(a)+1) = hn;
        end
        j = j+1;
    end
    % WIDTH
    W = min(h);
end
end