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Status: Shipped
Overview
Text v1 is Donner's first publishable text release. It covers base-tier <text> / <tspan> support, the text_full tier (HarfBuzz shaping), core <textPath>, and a compliance baseline against current SVG2 / CSS text-related specs.
Supported
- <text> and <tspan> rendering with per-character positioning and rotation
- text-anchor, textLength, lengthAdjust
- text-decoration (underline, overline, line-through)
- dominant-baseline and alignment-baseline
- @font-face with TTF, OTF (CFF), WOFF1, WOFF2
- Core <textPath> (startOffset, text-anchor, baseline-shift, rotate, transforms, subpaths)
- Base tier (stb_truetype) and full tier (HarfBuzz + FreeType)
Explicitly Deferred
- Full BiDi text support
- Advanced mixed-script vertical layout
- SVG2 text wrapping (inline-size, shape-inside)
- SVG2-only textPath features (side=right, path attribute)
- font shorthand, font-feature-settings, variable fonts
Test Coverage
- e-text-*: 30/30 passing
- e-tspan-*: 24/24 passing
- a-text-decoration-*: passing
- a-lengthAdjust-*: passing
- a-dominant-baseline-*: passing
- a-textLength-*: passing
- a-writing-mode-*: passing (advanced vertical cases disabled)
- e-textPath-*: 32/44 passing (22 custom goldens, 2 thresholds, 8 against resvg reference; 1 skipped bug, 11 deferred features)
Normative Spec Baseline
Text v1 uses the latest published W3C text-related specifications as of the release date. "CSS3" is treated here as the modern family of CSS modules, not a single monolithic spec.
- SVG text elements, DOM APIs, and SVG text attributes: SVG 2, 4 October 2018 Candidate Recommendation Snapshot. This is the primary SVG text source.
- Font properties and @font-face: CSS Fonts Module Level 4, 3 March 2026 Working Draft. This is the primary source for modern font behavior.
- Text decoration semantics: CSS Text Decoration Module Level 3, 5 May 2022 Candidate Recommendation Draft. This governs underline/overline/line-through behavior.
- Writing mode and vertical text interaction: CSS Writing Modes Level 4, 30 July 2019 Candidate Recommendation Snapshot. This governs writing-mode and related vertical layout behavior.
- Letter spacing, word spacing, and white-space processing: CSS Text Module Level 3, 30 September 2024 Candidate Recommendation Draft. This is the primary inline text spacing and whitespace source.
- Forward-looking text processing additions: CSS Text Module Level 4, 29 May 2024 Working Draft. This is informative for deferred features.
- Inline baseline terminology and alignment model: CSS Inline Layout Module Level 3, 18 December 2024 Working Draft. This is informative for baseline terminology and alignment references.
Compliance Matrix
Status legend: Shipped = implemented and covered by automated tests, Partial = core behavior works but some sub-features or edge cases are missing, Deferred = intentionally excluded from v1, OOS = out of scope (deprecated or not applicable).
SVG2 Text (§11) — Primary SVG text source
| Feature | Spec ref | Status | Coverage |
| <text> element | §11.2 | Shipped | 30/30 e-text-* |
| <tspan> element | §11.2 | Shipped | 24/24 e-tspan-* |
| <textPath> element | §11.8 | Shipped | 32/44 e-textPath-* (1 bug, 11 deferred) |
| <tref> element | — | OOS | Deprecated in SVG2 |
| Per-character positioning (x/y/dx/dy) | §11.4 | Shipped | e-text-*, e-tspan-* |
| Per-character rotation | §11.4 | Shipped | e-textPath-029 |
| text-anchor | §11.6 | Shipped | e-text-*, e-textPath-019 |
| textLength / lengthAdjust | §11.5.2 | Shipped | a-textLength-*, a-lengthAdjust-* |
| dominant-baseline | §11.10.2 | Shipped | a-dominant-baseline-* |
| alignment-baseline | §11.10.2 | Shipped | per-span override |
| baseline-shift | §11.10.3 | Shipped | e-textPath-032 |
| writing-mode horizontal | §11.7 | Shipped | a-writing-mode-* |
| writing-mode vertical | §11.7 | Partial | Basic Latin + CJK; mixed-script gaps |
| xml:space | §11.3 | Shipped | e-text-* |
| white-space CSS | §11.3 | Deferred | SVG2 adds CSS white-space |
| SVG DOM text APIs | §11.5 | Shipped | Unit tests |
| inline-size / text wrapping | §11.7.3 | Deferred | SVG2 auto-wrapping |
CSS Fonts Level 4
| Feature | Status | Coverage |
| font-family | Shipped | a-font-family-* |
| font-size | Shipped | e-text-* |
| font-weight (100-900, bold/normal) | Shipped | font matching |
| font-style (normal, italic, oblique) | Shipped | font matching |
| font-stretch | Shipped | font matching |
| font-variant: small-caps | Shipped | synthesized (base), native smcp (full) |
| @font-face with src: url() | Shipped | a-font-* |
| TTF, OTF (CFF), WOFF1, WOFF2 | Shipped | font loading tests |
| Generic font families | Shipped | a-font-family-* |
| font shorthand | Deferred | Individual properties only |
| font-feature-settings | Deferred | HarfBuzz supports internally |
| font-variation-settings | Deferred | Variable fonts |
| unicode-range | Deferred | |
CSS Text Decoration Level 3
| Feature | Status | Coverage |
| text-decoration: underline/overline/line-through | Shipped | a-text-decoration-* |
| Multiple decoration values | Shipped | Bitmask parsing |
| Decoration paint from declaring element | Shipped | CSS §3 |
| Decoration stroke | Shipped | |
| text-decoration-color | Deferred | Uses fill color |
| text-decoration-style | Deferred | Solid only |
| text-decoration-thickness | Deferred | Uses font metrics |
CSS Writing Modes Level 4
| Feature | Status | Coverage |
| writing-mode: horizontal-tb | Shipped | Default mode |
| writing-mode: vertical-rl | Partial | Basic Latin + CJK |
| Mixed-script vertical text | Deferred | 5 tests skipped |
| text-orientation | Deferred | |
| glyph-orientation-* | OOS | Deprecated in SVG2 |
CSS Text Level 3
| Feature | Status | Coverage |
| letter-spacing | Shipped | e-text-*, e-textPath-031 |
| word-spacing | Shipped | e-text-* |
| Whitespace processing (xml:space) | Shipped | e-text-* |
| BiDi text | Deferred | 1 test skipped |
textPath Status
All core textPath features are implemented and tested. 32 of 44 resvg tests pass (22 with custom goldens for glyph advance drift, 2 with AA thresholds, 8 against upstream resvg references). 1 test is skipped for a known bug, 11 for deferred features.
Bugs fixed during v1 stabilization
- Double text-anchor: applyTextAnchor() was applying a second linear shift to on-path glyphs. Fixed by marking path runs with TextRun.onPath.
- Missing kerning on path: Text-on-path repositioning only used xAdvance, losing per-glyph kerning. Fixed by preserving xKern in TextGlyph.
- Nested textPath leak: Content inside nested (invalid) <textPath> was rendered instead of hidden. Fixed in findApplicableTextPathEntity.
- textPath x/y applied: <textPath> x/y/dx/dy/rotate attributes were applied when the spec says to ignore them. Fixed by checking TextPathComponent in appendSpan.
- dy as perpendicular: dy on tspan within textPath was added to startOffset (along-path) instead of perpShift (perpendicular). Fixed.
- Invalid textPath whitespace: Hidden textPath content was collapsing surrounding inter-element whitespace. Fixed by blocking collapsing across textPath boundaries and making hidden spans reset adjacency tracking.
- Overflow pen position: When text overflows a path, the pen was set to (0,0) because the last glyph was hidden. Fixed by scanning for the last visible glyph.
- Post-path trailing space: Trailing whitespace from XML indentation inside <textPath> was placed on the path. Fixed by removing textPath trailing space during collapsing instead of the inter-element space.
Remaining known bug
| Test | Issue |
| 012 | Kerning on textPath — mixed textPath/tspan/textPath flat-text continuation |
Known Gaps
- e-tspan-030: Underline color inheritance uses text fill instead of tspan gradient fill. Passes with bumped threshold (900).
- e-textPath-012: Kerning on textPath with mixed textPath/tspan/textPath continuation.
- BiDi: Full bidirectional text support is deferred.
- Vertical mixed-script: Advanced mixed-script vertical layout is deferred.
- SVG2 text wrapping: inline-size, shape-inside, shape-subtract are deferred.
Future Work
- Fix e-textPath-012 (kerning on textPath).
- Add deeper dominant-baseline coverage and revisit BASE-table support.
- Add mixed-script vertical writing-mode parity.
1.15.0