PDF Creator

Create professional PDF documents from markdown with Chinese font support and theme system.

Quick Start

# Default theme (formal: Songti SC + black/grey, A4 print)
uv run --with weasyprint scripts/md_to_pdf.py input.md output.pdf

# Warm theme (training: PingFang SC + terra cotta)
uv run --with weasyprint scripts/md_to_pdf.py input.md --theme warm-terra

# Mobile theme (narrow page, large font — for phone reading / WeChat sharing)
uv run --with weasyprint scripts/md_to_pdf.py input.md --theme mobile

# Batch convert all markdown files with a specific theme
uv run --with weasyprint scripts/batch_convert.py *.md --theme warm-terra --no-preview

# No weasyprint? Use Chrome backend (auto-detected if weasyprint unavailable)
python scripts/md_to_pdf.py input.md --theme warm-terra --backend chrome

# List available themes
python scripts/md_to_pdf.py --list-themes dummy.md

Themes

Stored in themes/*.css. Each theme is a standalone CSS file.

To create a new theme: copy themes/default.css, modify, save as themes/your-theme.css.

Print vs Mobile: Choose the Right Theme

Decision rule: If the user does not specify, default to warm-terra for training/course content and default for formal documents. Ask "是否需要手机版？" only when the output channel is unclear.

Backends

The script auto-detects the best available backend based on content:

• CJK content detected → auto-selects Chrome (weasyprint subset-embeds PingFang SC as CID Type 0C OpenType, which macOS Preview / Adobe Reader fail to render — appears as garbled text on recipient devices even though it looks fine in Chrome's PDF viewer)
• Non-CJK content → auto-selects weasyprint (faster, no browser startup)

Override with --backend chrome or --backend weasyprint.

Batch Convert

# Default theme, same directory
uv run --with weasyprint scripts/batch_convert.py *.md

# Specific theme, output directory, skip previews for speed
uv run --with weasyprint scripts/batch_convert.py *.md --theme warm-terra --output-dir ./pdfs --no-preview

# Mobile theme for phone reading
uv run --with weasyprint scripts/batch_convert.py *.md --theme mobile --output-dir ./mobile-pdfs --no-preview

Anti-Pattern: Do NOT Manually Invoke pandoc + Chrome

Why this skill exists: Manual pandoc input.md -o out.html + chrome --headless --print-to-pdf workflows silently fail in ways that are hard to detect:

Rule: When the user asks for PDF conversion, ALWAYS use this skill. Never bypass it with manual pandoc/Chrome commands.

Troubleshooting

Chinese characters display as boxes: Ensure Chinese fonts are installed (Songti SC, PingFang SC, etc.)

weasyprint import error: Run with uv run --with weasyprint or use --backend chrome instead.

CJK text in code blocks garbled (weasyprint): The script auto-detects code blocks containing Chinese/Japanese/Korean characters and converts them to styled divs with CJK-capable fonts. If you still see issues, use --backend chrome which has native CJK support. Alternatively, convert code blocks to markdown tables before generating the PDF.

Chrome header/footer appearing: The script passes --no-pdf-header-footer. If it still appears, your Chrome version may not support this flag — update Chrome. Note: If you bypassed this skill and used manual Chrome headless, this is the first symptom — see "Anti-Pattern" section above.

Inline code with mixed CJK + ASCII shows blanks in macOS Preview (e.g. `Terminal/终端` renders only Terminal/ with the CJK part missing): weasyprint subset-embeds PingFang SC as OpenType (CID Type 0C), which strict PDF readers (macOS Preview / Adobe Reader) fail to render. Chrome's PDF viewer falls back automatically and hides the bug. Fix is in the default theme: code font-family chain prioritizes CID TrueType CJK fonts (Songti SC / Heiti SC) before OpenType ones (PingFang SC). To verify: pdfplumber + check font['fontname'] of CJK chars — if any references PingFang-SC (CID Type 0C OT), readers will likely fail. Reorder font chain to put CID TrueType first.

Table column 1 with short label gets mid-broken (e.g. 4/28（周|二）下|午): pandoc auto-emits <colgroup><col style="width:X%"> from dash counts in the markdown separator row. For | ----- | --- | --- | -------- | (uneven dash widths), pandoc allocates col 1 ~17% — too narrow for a 9-char CJK label. Inline style="" beats external CSS at equal specificity, so td:first-child { width:... } is silently shadowed. Fix is in default theme: table colgroup col { width: auto !important } neutralizes pandoc's hint, letting table-layout: fixed distribute equally (25% per column for a 4-col table). To verify: pandoc input.md -t html | grep colgroup — if it shows <col style="width:X%">, the bug applies. Scope: the neutralizer lives only in default.css; warm-terra and mobile themes use different strategies (nowrap on th/td with last-child wrap, and full-flow wrap respectively) and intentionally omit it. The neutralizer is locked in by scripts/tests/test_cjk_tables.py::test_default_theme_neutralizes_pandoc_colgroup_hint.

Visual Self-Check (MANDATORY — Do Not Skip)

This is not optional. After every PDF generation, the script automatically:

1. Converts each page to PNG via pdftoppm (poppler-utils) into a <pdf-name>/ subdirectory under the system temp dir (NOT next to the PDF — previews are a throwaway self-check artifact and must never linger in your working tree / git repo). The exact path is printed after the run as Previews: <path>/page-NN.png
2. Prints a structured self-check checklist reminding the caller to visually inspect each page
3. Runs typography lint to detect CJK line-break anti-patterns

Why mandatory: "PDF generated cleanly" ≠ "rendering matches markdown intent". Common silent failures include:

• Paragraphs collapsing into one (CommonMark soft-break on consecutive non-blank lines)
• Tables overflowing page margins
• Missing CJK / emoji glyphs
• Code block garbling
• Chrome default headers/footers (if bypassed this skill)

Workflow: After running the script, Read each page-NN.png at the printed Previews: path and verify against the markdown source. If anything renders differently from intent, fix the markdown (use - real lists instead of pseudo-lists, insert blank lines, restructure tables) and rerun. The script does NOT silently "fix" non-standard markdown — that would mask the signal that the source is wrong, causing the same markdown to render incorrectly in other processors (Obsidian, GitHub, VS Code preview).

Disable with --no-preview for batch / non-interactive runs:

python scripts/md_to_pdf.py input.md output.pdf --no-preview

Requires pdftoppm (brew install poppler on macOS). If not installed, the script logs a hint and skips preview generation but still produces the PDF.

CJK Typography (default behavior)

The script applies two layers of CJK-aware processing automatically — without modifying the user's markdown source or theme CSS files:

Layer 1: CSS patch (auto-injected, fixes ~80% of cases)

_load_theme() appends a CJK typography CSS patch to the loaded theme CSS. The patch:

• table { table-layout: fixed; width: 100% } — equal column widths prevent weasyprint auto-layout from squeezing one column to ~10% width when an adjacent column has 5x more content
• td, th { word-break: keep-all; overflow-wrap: normal; line-break: strict } — don't slice CJK characters apart. The deliberate trade-off encoded by overflow-wrap: normal (not break-word) is to let content overflow slightly rather than fall back to mid-token breaks — rationale documented in md_to_pdf.py L109-146 inline comments and locked in by scripts/tests/test_cjk_tables.py
• th { white-space: nowrap } — short headers stay one line for predictable column widths

This silently fixes the most common anti-pattern (cell content forcibly wrapped between CJK characters producing single-char-only lines), without touching the user's source. The user's theme CSS file on disk is never modified.

Layer 2: Typography lint (post-render detection, catches the rest)

After PDF generation, the script runs pdftotext -layout per page and scans for known CJK anti-patterns per "中文文案排版指北" (Chinese typography style guide):

• Single CJK character alone on a line (cell still too narrow even after Layer 1)
• Line ending with （ followed by content next line (broken bracket pair)
• Line starting with ） (broken from previous bracket pair)
• Short line ending with mid-thought punctuation 、，；：

Findings are printed to stderr with page+line locations. They are warnings, not errors — PDF still generates. The author sees the finding and decides:

1. Accept (e.g. one orphan char in a long doc may be acceptable)
2. Shorten the offending cell content to fit the column width
3. Restructure (e.g. move long content into a paragraph below the table)

Why not silently auto-fix everything?

Layer 2 deliberately does NOT modify the markdown. Per CLAUDE.md "禁止隐式行为" rule: silently rewriting non-standard markdown (e.g. expanding pseudo-lists into real lists) would mask the signal that the source is wrong, causing the same markdown to render incorrectly in other processors. Layer 1 is acceptable because it patches rendering behavior for already-standard markdown (a standard table that weasyprint happens to render imperfectly for CJK), not the markdown source itself.

Known limitations

When a single cell's content is just slightly longer than the available column width (e.g. 10 CJK chars in a 9-char-wide cell after equal split), weasyprint will fall back to forced break despite keep-all. Layer 1 cannot fix this — Layer 2 will catch it and prompt the author to shorten cell content or restructure.