LibGfx+LibWeb: Apply word-spacing to word separator advances

[tcl3]

Previously, word-spacing was only consulted by the tab-size advance formula. Space glyphs never received it.

Text shaping now adds the computed word-spacing to the advance of each word separator glyph. The space and no-break space are word separators. The line feed is treated the same way, because whitespace collapsing can leave it in shaped text, where it behaves as a space.

I've included a fix to the WPT test importer, which previously mangled the path to resources that were included in multiple files (i.e: the test file and the reference file).

[coderabbitai]

📝 Walkthrough

Walkthrough

The PR adds word-spacing to native and Rust text shaping. It applies spacing to word separators and includes it in shaping-cache keys. Shaping now returns trailing-whitespace length and advance. Inline layout stores this metadata in items and fragments, then trims trailing whitespace from recorded metrics. New WPT tests cover word-spacing across inline, block, table, percentage, preserved-whitespace, and negative-value cases.

Sequence Diagram(s)

sequenceDiagram
  participant Layout
  participant shape_text_with_font
  participant ladybird_gfx_shape_text
  participant GfxShapeText
  Layout->>shape_text_with_font: request text shaping with word_spacing
  shape_text_with_font->>ladybird_gfx_shape_text: pass word_spacing
  ladybird_gfx_shape_text->>GfxShapeText: shape text and request trailing-whitespace metrics
  GfxShapeText-->>ladybird_gfx_shape_text: return glyphs and metrics
  ladybird_gfx_shape_text-->>shape_text_with_font: return shaped run
  shape_text_with_font-->>Layout: store glyphs and trailing-whitespace data

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Possibly related PRs

• LadybirdBrowser/ladybird#10907: Related text-layout changes in inline_level_iterator.rs and word-spacing-aware shaping.

🚥 Pre-merge checks | ✅ 3

✅ Passed checks (3 passed)

Check name	Status	Explanation
Description check	✅ Passed	The description directly explains the word-spacing text-shaping changes and the WPT importer fix included in the changeset.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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[coderabbitai]

Actionable comments posted: 2

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@Libraries/LibWeb/Rust/src/layout/line_box.rs`:
- Around line 191-201: Update the trailing-whitespace trimming logic around
last_fragment_index so it continues inspecting preceding fragments after a
whitespace-only fragment is reduced to zero. Accumulate and remove eligible
trailing whitespace across inline-node or font boundaries, while retaining
required zero-length inline fragments and keeping
trailing_whitespace_inline_size() accurate.

In
`@Tests/LibWeb/Ref/expected/wpt-import/css/css-text/word-spacing/word-spacing-001-ref.html`:
- Line 25: Close all four nested span elements opened in the reference markup by
adding the corresponding closing tags before the closing div, preserving the
existing text and nesting order.

🪄 Autofix

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro Plus

Run ID: a59d5915-b3a5-4314-827a-c30658595a50

📥 Commits

Reviewing files that changed from the base of the PR and between efb6f45 and abeec8a.

📒 Files selected for processing (36)

• Libraries/LibGfx/Font/Font.h
• Libraries/LibGfx/Rust/src/text_layout.rs
• Libraries/LibGfx/TextLayout.cpp
• Libraries/LibGfx/TextLayout.h
• Libraries/LibWeb/Painting/DisplayListRecorder.cpp
• Libraries/LibWeb/Rust/src/layout/font.rs
• Libraries/LibWeb/Rust/src/layout/inline_formatting_context.rs
• Libraries/LibWeb/Rust/src/layout/inline_level_iterator.rs
• Libraries/LibWeb/Rust/src/layout/line_box.rs
• Libraries/LibWeb/Rust/src/layout/line_box_fragment.rs
• Libraries/LibWeb/Rust/src/layout/line_builder.rs
• Meta/import-wpt-test.py
• Tests/LibWeb/Ref/expected/wpt-import/css/CSS2/text/word-spacing-applies-to-001-ref.xht
• Tests/LibWeb/Ref/expected/wpt-import/css/CSS2/text/word-spacing-applies-to-007-ref.xht
• Tests/LibWeb/Ref/expected/wpt-import/css/CSS2/text/word-spacing-applies-to-012-ref.xht
• Tests/LibWeb/Ref/expected/wpt-import/css/css-text/word-spacing/reference/ref-filled-green-100px-square.xht
• Tests/LibWeb/Ref/expected/wpt-import/css/css-text/word-spacing/word-spacing-001-ref.html
• Tests/LibWeb/Ref/expected/wpt-import/css/css-text/word-spacing/word-spacing-002-ref.html
• Tests/LibWeb/Ref/expected/wpt-import/css/css-text/word-spacing/word-spacing-003-ref.html
• Tests/LibWeb/Ref/input/wpt-import/css/CSS2/text/word-spacing-applies-to-001.xht
• Tests/LibWeb/Ref/input/wpt-import/css/CSS2/text/word-spacing-applies-to-002.xht
• Tests/LibWeb/Ref/input/wpt-import/css/CSS2/text/word-spacing-applies-to-005.xht
• Tests/LibWeb/Ref/input/wpt-import/css/CSS2/text/word-spacing-applies-to-006.xht
• Tests/LibWeb/Ref/input/wpt-import/css/CSS2/text/word-spacing-applies-to-007.xht
• Tests/LibWeb/Ref/input/wpt-import/css/CSS2/text/word-spacing-applies-to-008.xht
• Tests/LibWeb/Ref/input/wpt-import/css/CSS2/text/word-spacing-applies-to-009.xht
• Tests/LibWeb/Ref/input/wpt-import/css/CSS2/text/word-spacing-applies-to-010.xht
• Tests/LibWeb/Ref/input/wpt-import/css/CSS2/text/word-spacing-applies-to-011.xht
• Tests/LibWeb/Ref/input/wpt-import/css/CSS2/text/word-spacing-applies-to-012.xht
• Tests/LibWeb/Ref/input/wpt-import/css/CSS2/text/word-spacing-applies-to-013.xht
• Tests/LibWeb/Ref/input/wpt-import/css/CSS2/text/word-spacing-applies-to-014.xht
• Tests/LibWeb/Ref/input/wpt-import/css/CSS2/text/word-spacing-applies-to-015.xht
• Tests/LibWeb/Ref/input/wpt-import/css/css-text/word-spacing/word-spacing-001.html
• Tests/LibWeb/Ref/input/wpt-import/css/css-text/word-spacing/word-spacing-002.html
• Tests/LibWeb/Ref/input/wpt-import/css/css-text/word-spacing/word-spacing-003.html
• Tests/LibWeb/Ref/input/wpt-import/css/css-text/word-spacing/word-spacing-negative-value-001.html