Where to get Ruler

Activity | Source

About Ruler


Ruler is a simple collection of measurement tools that are displayed on the screen.

120px-Ruler-fig1 120px-Ruler-fig2 120px-Ruler-fig3 120px-Ruler-fig4
CM and MM scales CM and MM grid Angles Checkerboard

Since the OLPC XO computer has a 200 DPI display, the rulers are quite accurate. One other hardware, where the display resolution is not known, their is a spinner to let the user set the DPI. Ruler saves this value to the Journal, so it need not be set on subsequent uses of the Activity.



From left to right:

  • Activity menu button
  • CM and MM ruler
  • CM and MM grid
  • Angles (protractor)
  • Checkerboard
  • Dots per inch (DPI) spinner – used to set the display DPI – only appears when DPI is not known, e.g., non-OLPC-XO hardware
  • Stop button (not shown)