boolean interchanged = false;
        int x = x1;
        int y = y1;
        int deltax = Math.abs(x2 - x1);
        int deltay = Math.abs(y2 - y1);
        int s1 = (int) Math.signum(x2 - x1);
        int s2 = (int) Math.signum(y2 - y1);

        if (deltay > deltax) {
            int aux = deltax;
            deltax = deltay;
            deltay = aux;
            interchanged = true;

        } else {
            interchanged = false;
        }

        int error = 2 * deltay - deltax;

        for (int i = 0; i <= deltax; ++i) {
            if ((x >= 0) && (y >= 0) && (y < cnv.getheight()) && (x < cnv.getlength())) {
                b.setRGB(x, y, c.getRGB());
            }

            while (error > 0) {
                if (interchanged) {
                    x += s1;
                } else {
                    y += s2;
                }

                error -= 2 * deltax;
            }

            if (interchanged) {
                y += s2;
            } else {
                x += s1;
            }
            error += 2 * deltay;
        }