bresenham.m

function [x, y, v] = bresenham(x1, y1, x2, y2)

%Matlab optmized version of Bresenham line algorithm. No loops.
%Format:
%               [x y]=bham(x1,y1,x2,y2)
%
%Input:
%               (x1,y1): Start position
%               (x2,y2): End position
%
%Output:
%               x y: the line coordinates from (x1,y1) to (x2,y2)
%
%Usage example:
%               [x y]=bham(1,1, 10,-5);
%               plot(x,y,'or');

x1 = round(x1);
x2 = round(x2);

y1 = round(y1);
y2 = round(y2);

dx = abs(x2-x1);
dy = abs(y2-y1);

steep = abs(dy) > abs(dx);

if steep
    t = dx;
    dx = dy;
    dy = t;
end

%The main algorithm goes here.
if dy == 0 
    q = zeros(dx+1,1);
else
    q = [0;diff(mod((floor(dx/2):-dy:-dy*dx+floor(dx/2))',dx))>=0];
end

%and ends here.

if steep
    if y1 <= y2
        y = (y1:y2)';
    else
        y = (y1:-1:y2)';
    end
    
    if x1 <= x2
        x = x1 + cumsum(q);
    else
        x = x1 - cumsum(q);
    end
else
    if x1 <= x2
        x = (x1:x2)';
    else
        x = (x1:-1:x2)';
    end
    
    if y1 <= y2
        y = y1 + cumsum(q);
    else
        y = y1-cumsum(q);
    end
end

if (nargout > 2)
    v = ones(size(x));
end