Rouler / Ruler

Length of ruler is limited. But when you draw the line, or cut the length of the longer than the length of the ruler to be truncated. In this case, moving the ruler to draw the line twice. But the line is not straight. I would like to resolve this problem.

The ruler is longer a straight line, the cross is not easy. Move the ruler. In addition, although being in a straight line, draw the line, the cross was not easy. Move the ruler by using the wheel, you can only push in the direction you want. It also helped to move the wheels in a straight line to the ruler were to avoid the line.