GoKawiilRaph Levien builds JIT renderer for proportional bitmap fonts on RP2350 chips
Developer Raph Levien has described a new technique for rendering proportional, kerned bitmap text at high speed on microcontrollers like the RP2350, built for his vic-2350 project that reimagines an 1980s home computer. The method generates optimized machine code on the fly for each string using a just-in-time compiler, avoiding the fixed-character-cell limitations common in microcontroller text rendering. Levien says the approach integrates with his 'race-the-beam' renderer but would also work for writing to a standard framebuffer.
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The work revives bitmap font aesthetics that Levien argues remain visually preferable to antialiased text at low resolutions, suggesting a continued niche for crisp pixel fonts even as most modern displays favor smooth rendering. By using JIT compilation to achieve proportional spacing without the performance cost typically associated with variable-width characters, the technique could make richer typography practical on cheap, resource-constrained microcontroller hardware. This could be of particular interest to hobbyists and retrocomputing projects aiming to replicate vintage computer displays with modern low-power chips.
- Raph Levien's vic-2350 project reimagines an 80s-style home computer using the RP2350 microcontroller.
- The new technique uses just-in-time code generation to render proportional, kerned bitmap text quickly on limited hardware.
- The method works with Levien's custom race-the-beam renderer and could also apply to standard framebuffer rendering.
Raspberry Pi Pico 2 (RP2350) — This article dives deep into JIT bitmap text rendering tricks on the RP2350, so grabbing the actual board is the perfect way to follow along and experiment yourself. It's a cheap, capable microcontroller ideal for retro-computing projects like vic-2350. Great for tinkerers who want to try race-the-beam rendering firsthand.
See Raspberry Pi Pico 2 (RP2350) on Amazon → Affiliate link — we may earn a commission on purchases, at no extra cost to you. Product picked by AI based on this article; it is not a tested recommendation.Source: linebender.org, 2026-11-08
Published there as: “JIT bitmap text rendering for microcontrollers”
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