Fractional scales, fonts and hinting

Original Article ↗ Hacker News Discussion ↗

Overall reaction to GTK font-rendering changes

  • Many long-time GTK users are pleased; screenshots show a large improvement in sharpness vs earlier GTK4.
  • Some want comparisons vs older stacks (e.g., GTK 3 with pre-1.44 Pango), where they recall crisper text.
  • A few argue GTK 3 still looks better than GTK 4, even after the new work.

Hinting, subpixel AA, and rendering philosophies

  • Discussion contrasts:
    • Shape-preserving, slightly blurry rendering (often associated with Apple).
    • Pixel-grid–aligned, crisper but shape-distorting rendering (often associated with older Windows/ClearType).
  • Several note subpixel AA is being dropped by many toolkits (GTK, modern Apple, some MS stacks) in favor of grayscale AA plus HiDPI.
  • Disagreements:
    • Some find grayscale AA “good enough” even at ~100–110 DPI.
    • Others insist subpixel AA is still noticeably sharper on common 1080p/1440p/4K@150% screens.
  • There’s debate whether subpixel AA is worth its downsides (color fringing, device-dependent geometry, bad screenshots) on modern panels.

HiDPI, fractional scaling, and multi-monitor setups

  • GTK previously used 2x rendering plus downscale; now it does per-widget fractional scaling, which is seen as more efficient but harder to get right.
  • New gtk-hint-font-metrics behavior is welcomed; it now auto-applies based on display DPI, improving mixed-DPI setups.
  • Comparisons:
    • macOS: renders at higher virtual resolution and relies on HiDPI; can look awkward on non-HiDPI external displays, especially since subpixel AA removal.
    • Windows: some praise per-monitor DPI scaling; others report blurry UI, many confusing settings, and brittle app compatibility.
    • Haiku and older Windows APIs use font-size–based layout units; some see this as elegant, others say it burdens developers.

Gamma correction, FreeType tuning, and configs

  • Several argue Linux font rendering is often wrong due to missing or incorrect gamma correction, especially for light-on-dark text.
  • Workarounds mentioned:
    • FreeType properties (e.g., stem darkening and interpreter version) can significantly change perceived weight and sharpness.
    • Environment variables and flags for Electron/Chromium apps to use Wayland and better font paths.
  • There’s disagreement over whether changes in FreeType “broke” grid-fitting or just shifted to match different font eras.

Residual concerns

  • Some still see fuzziness in GTK screenshots and question lack of subpixel AA and full horizontal+vertical hinting.
  • Complexity of doing text rendering “perfectly” across devices and DPIs is widely acknowledged as high and contentious.