PIL antialiases TTF outlines by default; a 'pixel-style' font only
rasterizes without antialiasing at specific sizes (for PressStart2P:
exact multiples of its 8px design grid). A ladder rung at an unverified
size silently renders blurry on an LED panel — this exact bug shipped in
both text-display's and football-scoreboard's custom TTF ladders
(non-8-multiple PressStart2P sizes, and '5by7.regular'/'4x6-font' at
sizes that were never actually crisp).
measure_font_crispness(font, sample_text) renders the sample and reports
the fraction of ink-bbox pixels that are neither pure black nor pure
white. BDF fonts (real bitmaps) always score 0.0; TTF ladders should be
verified against this before shipping — see the new
TestFontFitting::test_ladder_arcade_is_crisp pattern.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>