Use a ruler to measure Euclidean distances in the display. Click inside the display with the left mouse button and drag while keeping the mouse button pressed. This will display a ruler along the picked line showing the distances.
Authored by Steve Dugaro at www.cecm.sfu.ca using www.javaview.de (c) July 2000
ctrl + v : launch control panel
s + mouse : zoom in/out
x + mouse : zoom in rectangle
t + mouse : translate view