Ruler

300px-Ruler.jpg

Where to get Ruler

Activity | Source

About Ruler

Ruler-icon.png

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.

Toolbar

Ruler-toolbar.png

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)