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feat: Port text rendering from ttf-parser to skrifa (including fontdb)#1009

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feat: Port text rendering from ttf-parser to skrifa (including fontdb)#1009
oetiker wants to merge 1 commit into
linebender:mainfrom
oetiker:skrifa-minimal

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@oetiker oetiker commented Jan 13, 2026 •
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Summary

This replaces ttf-parser with skrifa for all font parsing and text rendering.

This is an alternative approach to #922 - see comparison below.

fontdb changes:

  • Vendor fontdb 0.23.0 as a workspace crate
  • Replace ttf-parser with skrifa for font parsing
  • Use skrifa's MetadataProvider for font attributes and metrics

usvg changes:

  • Add skrifa_colr.rs: COLR glyph painting using skrifa's ColorPainter
  • Add skrifa_metrics.rs: Font metrics extraction using skrifa
  • Update flatten.rs: Use skrifa for glyph outlines and bitmap extraction
  • Update layout.rs: Use skrifa for font metrics and harfrust for shaping
  • Replace rustybuzz with harfrust for text shaping
  • Update test reference images for new skrifa-based rendering

Comparison with #922

Aspect This PR #922
Based on main (includes variable fonts #997, Rust 2024) older base
Tests All passing ✅ 23 failing
fontdb Vendored and modified Uses existing fontdb
COLR impl New skrifa_colr.rs using ColorPainter Modified existing colr.rs
Diff size +2530/-375 (larger due to vendored fontdb) +498/-302

Key differences:

  • This PR vendors fontdb to enable the skrifa migration at the font database level
  • This PR is rebased on current main, so it includes variable font support and other recent changes
  • This PR has all tests passing with updated reference images

Test plan

  • All existing tests pass (cargo test --workspace)
  • Reference images updated for skrifa-based rendering

🤖 Generated with Claude Code
@oetiker

oetiker commented Jan 13, 2026

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Diff images:

tests_text_font-variation-settings_auto-font-stretch-condensed tests_text_font-variation-settings_wght-100 tests_text_font-variation-settings_xtra-extreme tests_text_font-variation-settings_wdth-25 tests_text_font-variation-settings_wght-700 tests_text_text_zalgo tests_text_color-font_colrv0 tests_text_color-font_colrv1 tests_text_font-variation-settings_opsz-144 tests_text_font-variation-settings_explicit-overrides-auto tests_text_font-variation-settings_grad-negative tests_text_font-variation-settings_multiple-axes tests_text_font-variation-settings_auto-font-style-oblique tests_text_font-variation-settings_auto-font-weight-700 tests_text_font-variation-settings_wdth-151 tests_text_font-variation-settings_all-axes-combined tests_text_font-variation-settings_slnt-negative
@oetiker @claude
Port text rendering from ttf-parser to skrifa
fe95143 
This replaces ttf-parser with skrifa for all font parsing and text rendering.

fontdb changes:
- Vendor fontdb 0.23.0 as a workspace crate
- Replace ttf-parser with skrifa for font parsing
- Use skrifa's MetadataProvider for font attributes and metrics

usvg changes:
- Add skrifa_colr.rs: COLR glyph painting using skrifa's ColorPainter
- Add skrifa_metrics.rs: Font metrics extraction using skrifa
- Update flatten.rs: Use skrifa for glyph outlines and bitmap extraction
- Update layout.rs: Use skrifa for font metrics and harfrust for shaping
- Replace rustybuzz with harfrust for text shaping
- Update test reference images for new skrifa-based rendering

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
@oetiker oetiker changed the title Port text rendering from ttf-parser to skrifa Jan 30, 2026
@oetiker oetiker changed the title feat: Port text rendering from ttf-parser to skrifa Jan 30, 2026
@oetiker

oetiker commented Jan 30, 2026

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anything I can do to herd this along ?
@oetiker oetiker mentioned this pull request Feb 4, 2026
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