razbakov/latex-pdf

LaTeX PDF Generator

Generate professional PDF documents by writing a Python script that constructs LaTeX source strings and compiles them to PDF using Tectonic. No TeX distribution installation required — Tectonic auto-downloads packages on first use.

Approach

1. Python script builds LaTeX content as a string using f-strings/concatenation
2. Write the string to a .tex file
3. Compile with tectonic <file>.tex → produces .pdf in the same directory

This approach is preferred over HTML-to-PDF or JS-based PDF libraries because LaTeX produces typographically superior output with precise control over layout, tables, math, headers/footers, and page breaks.

When NOT to use LaTeX:

• Presentations / slide decks — LaTeX produces ugly, hard-to-brand slides. Use the image-from-html skill instead (HTML/CSS slides → Chrome headless → PNG → PDF). HTML gives pixel-perfect brand control that LaTeX can't match.
• Branded marketing materials — posters, social graphics, flyers. Use image-from-html for exact brand guideline matching.

When to use LaTeX:

• Reports, invoices, CVs, academic papers, data-heavy documents with tables and statistics — anything that benefits from precise typographic control over text-heavy content.

Prerequisites

• Python 3 (standard library only — no pip packages needed)
• Tectonic: brew install tectonic (macOS) or cargo install tectonic

Quick Start

import subprocess
from pathlib import Path

def generate_report(data: dict, output_path: Path):
    tex = build_latex(data)
    tex_path = output_path.with_suffix(".tex")
    tex_path.write_text(tex)
    result = subprocess.run(
        ["tectonic", str(tex_path)],
        capture_output=True, text=True,
    )
    if result.returncode != 0:
        raise RuntimeError(f"tectonic failed:\n{result.stderr}")

Essential LaTeX Helpers

Always include these in the Python script:

def esc(text: str) -> str:
    """Escape LaTeX special characters."""
    for old, new in [
        ("\\", "\\textbackslash{}"), ("&", "\\&"), ("%", "\\%"),
        ("$", "\\$"), ("#", "\\#"), ("_", "\\_"),
        ("{", "\\{"), ("}", "\\}"),
        ("~", "\\textasciitilde{}"), ("^", "\\textasciicircum{}"),
    ]:
        text = text.replace(old, new)
    return text

def pct(v: float, decimals: int = 1) -> str:
    """Format a 0-1 value as a LaTeX percentage."""
    return f"{v * 100:.{decimals}f}\\%"

Document Structure

Key Patterns

Compile with Tectonic

result = subprocess.run(
    ["tectonic", str(tex_path)],
    capture_output=True, text=True,
)
if result.returncode != 0:
    print(result.stderr)
    sys.exit(1)

Tectonic downloads LaTeX packages automatically on first run. No tlmgr or TeX Live needed. It produces the PDF in the same directory as the .tex file.