PDF Engine (MVP)

Developer notes for the minimal, reliable PDF exporter (the app's only PDF engine).

Location & Entry Points

• Code: src/utils/pdf_mvp/ (browser entry index.js, layout in pure.js)
• Entry: downloadSingleSongPdf(song), downloadMultiSongPdf(songs), downloadSongbookPdf(songs, opts), and planSingleSong(song)

Decision Ladder

1. 1‑column, single page at sizes 16 → 12 pt
2. 2‑column, single page at sizes 16 → 12 pt
3. Fallback: 1‑column multipage at 15 pt (title/key header only on page 1)

Typography & Spacing

• Title: 26 pt, bold; wraps as needed
• Key: 16 pt, italic gray (rgb(90,90,90)), tight under title
• Lyrics: 12–16 pt, line‑height ≈ 1.2×
• Section headers: same size as lyrics (bold), rendered as [LABEL]
• Header gap: ≈ 1.125× lyric line‑height before first section

Chords

• Drawn on their own line above the wrapped lyric line
• Align above the exact lyric characters they precede
• Enforce ≥ one space width between successive chords; nudge minimally
• Trailing chords flush to end‑of‑line with a single‑space separation

Columns & Paging

• Page margins: 0.5" on all sides
• Two columns use a 24 pt gutter and equal widths
• Sections are atomic and never split across columns/pages

Fonts

• Preferred: Noto Sans (Regular/Italic/Bold) and Noto Sans Mono (Regular/Bold)
• Place font files under apps/web/src/assets/fonts/ (imported with ?url and registered at runtime)
• Falls back to jsPDF built‑ins (helvetica/courier) if Noto is unavailable

Tests

• Run: npm run test:mvp
• Suites: src/__tests__/pdf_mvp.*.test.js (plan, chords, sections, pure, songbook)

Do Not Regress

• Title 26 pt; Key 16 pt gray; lyric/chord 12–16 pt; line‑height ≈ 1.2×
• Minimal 1‑space chord separation; chords align over matching lyric characters
• Sections never split; header gap ≈ 1.125× lyric line

See also PDF-and-Printing.