# Extended Caption Styling Implementation Summary

**Date:** 2026-09-22 10:37
**Task:** Implement extended caption styling (font selection, drop shadow, dimmed text color, background toggle)

## Changes Made

### Task 1: Data model (commit `a4a1376`)
- **`src/lib/stores/preferences.svelte.ts`**: Extended `CaptionSettings` interface with 8 new fields: `fontFamily`, `backgroundEnabled`, `shadowEnabled`, `shadowDepth`, `shadowColor`, `dimmedColorMode`, `dimmedOpacity`, `dimmedColor`
- **`src-tauri/src/models.rs`**: Extended `CaptionStyle` Rust struct with matching fields (snake_case, serde camelCase)
- **`src/lib/bindings/export.ts`**: Extended TS `CaptionStyle` binding interface
- **`src/lib/components/ExportDialog.svelte`**: Updated captionStyle passthrough to include all 17 fields

### Task 2: System font detection (commit `1447071`)
- **`src-tauri/src/commands/media_analysis.rs`**: Added `list_system_fonts` command using `fc-list :lang=en family` with hardcoded fallback (8 common fonts)
- **`src-tauri/src/lib.rs`**: Registered new command in `generate_handler!`
- **`src/lib/bindings/mediaAnalysis.ts`**: Added `listSystemFonts()` TS binding

### Task 3: ASS generation wiring (commit `2cf8cdc`)
- **`src-tauri/src/services/clip_exporter.rs`**: Rewrote style extraction block in `vtt_to_ass_with_karaoke()`:
  - Uses `font_family` instead of hardcoded `Arial`
  - Dimmed color: auto mode derives from `textColor` + `dimmedOpacity`, custom mode uses `dimmedColor` directly
  - Background/shadow mutual exclusivity: background mode (BorderStyle 3/4 + BackColour for box), shadow mode (BorderStyle 1 + BackColour for shadow + Shadow depth), or neither (transparent BackColour)

### Task 4: Preview caption rendering (commit `bc39c2a`)
- **`src/lib/components/VideoPlayer.svelte`**: Updated `captionStyle` derived to use `$derived.by()`, computing:
  - `fontFamily`, `fontWeight` from settings
  - Background conditional on `backgroundEnabled` with `rgba()` using `hexToRgb` helper
  - Shadow conditional on `shadowEnabled` with depth/color
  - Dimmed word colors: auto mode uses opacity, custom mode uses direct color

### Task 5: Settings panel UI (commit `5c47e38`)
- **`src/lib/components/CaptionSettingsPanel.svelte`**: Full rewrite with:
  - System font dropdown (loaded on mount via `listSystemFonts()`, each option styled in its own font)
  - Font size slider, bold checkbox
  - Text color picker
  - Dimmed text: auto/custom radio toggle with opacity slider or color picker
  - Outline: checkbox + color picker
  - Background: checkbox + color picker + opacity slider (disables shadow when enabled)
  - Drop shadow: checkbox + depth slider + color picker (disables background when enabled)
  - Position: bottom/top radio
  - Word highlight checkbox
  - Reset to defaults button
  - 320px width, scrollable, dark theme

### Task 6: Verification
- `cargo build`: Clean (6 pre-existing warnings)
- `cargo test --lib services::clip_exporter::tests`: 23/23 passing
- `npm run check`: Only 4 pre-existing errors (node:path/process/url, overload)

## Approach
- Used Subagent-Driven Development: fresh subagent per task + task reviewer per task
- 5 implementer dispatches + 5 reviewer dispatches + 1 verification pass
- All reviews approved on first pass (no fix cycles needed)

## Minor Items for Future
- Font-family CSS quoting for multi-word names (e.g., `Times New Roman`) in dropdown options
- No defensive mutual exclusivity check in preview rendering (relies on settings panel enforcement)
- `hexToRgb` has no malformed-hex guard (UI-controlled values only)
- `dimmedColorMode` is `string` in Rust/TS binding vs `'auto' | 'custom'` union in preferences
- No ASS Style-line unit tests for new field combinations

## Follow-up Items
- Manual smoke test with `cargo tauri dev` recommended
- Test font selection with burn-in export
- Verify dimmed color auto vs custom modes in both preview and export