Line Tool
The Line tool allows you to draw straight lines.
To use this tool...
After selecting the colours you will be drawing with, click on the Line button and point the cursor where you want the line to start. Hold down the left mouse button to draw with the foreground colour; hold down the right mouse button to draw with the background colour. Drag the cursor to the other end of the line and release the mouse button. To change the width of the Line tool, double-click on the Line button.