Notebook · Field note
Why the “now serving” number jittered
A field note from Via. The board looked broken, and the cause was the typeface.
Draft for review
On the display board for Via, the “now serving” number twitched every time it changed. Nothing was wrong with the code. The typeface had proportional figures: a 1 is narrower than a 4, so 041 and 044 had different widths, and the whole number shifted sideways each time it ticked.
From across a room, that movement reads as a glitch. People look at the board to know where they stand. A board that seems to stutter makes them doubt it.
The fix was not a CSS trick. I changed the typeface to one with tabular figures, where every digit has the same width. The number now changes in place.
The lesson I keep: a number on a screen is an interface. Test it on the real screen, at the real distance, with real changes, before trusting it. This site uses Geist for the same reason, and every figure here is set with tabular numerals.