razbakov/image-from-latex

LaTeX-to-Image Technique

Generate high-quality images from LaTeX/TikZ source, compiled to PDF with Tectonic and rasterized to PNG with ImageMagick.

When to use

• You need precise geometric shapes, gradients, and text positioning
• Thumbnails (YouTube 16:9, Shorts 9:16) with bold typography
• Diagrams, infographics, or stylized graphics with exact control
• Output must be vector-sharp at any resolution

When NOT to use

• Complex layouts with many HTML-like elements → use image-from-html
• Photo-realistic or illustrative imagery → use image-from-gemini
• Multi-page documents → use latex-pdf skill directly

Requirements

• tectonic: brew install tectonic (auto-downloads LaTeX packages)
• magick (ImageMagick): brew install imagemagick
• python3 (standard library only)

Workflow

1. Write a Python script that builds TikZ source

import subprocess
from pathlib import Path

PREAMBLE = r"""
\documentclass[tikz,border=0pt]{standalone}
\usepackage[T1]{fontenc}
\usepackage{lmodern}
\usepackage{tikz}
\usetikzlibrary{calc,positioning,fadings}
\usepackage{xcolor}
\begin{document}
"""
POST = r"\end{document}"

F = r"\sffamily\bfseries"  # bold sans-serif shorthand

2. Compile with Tectonic

def compile_tex(tex_content, name, out_dir):
    p = Path(out_dir) / f"{name}.tex"
    p.write_text(tex_content)
    r = subprocess.run(["tectonic", str(p)], capture_output=True, text=True)
    if r.returncode != 0:
        print(f"FAIL {name}: {r.stderr[:500]}")
        return False
    print(f"OK {name}")
    return True

3. Convert PDF to PNG

# 16:9 landscape (1280x720)
magick -density 300 output.pdf -resize 1280x720! -quality 95 output.png

# 9:16 vertical (1080x1920)
magick -density 300 output.pdf -resize 1080x1920! -quality 95 output.png

# A4 print (300 DPI)
magick -density 300 output.pdf -quality 95 output.png

4. Display the result

Use the Read tool on the generated PNG to show it inline.

Helpers

Shadow text (drop shadow for depth)

def st(x, y, text, size, color, anchor="west", sop=0.5, ox=0.12, oy=-0.12):
    fs = rf"{F}\fontsize{{{size}}}{{{size+2}}}\selectfont"
    return (
        rf"  \node[anchor={anchor}, font={fs}, text=black, opacity={sop}] at ({x+ox},{y+oy}) {{{text}}};" "\n"
        rf"  \node[anchor={anchor}, font={fs}, text={color}] at ({x},{y}) {{{text}}};"
    )

def stc(x, y, text, size, color, sop=0.5, ox=0.08, oy=-0.08):
    return st(x, y, text, size, color, anchor="center", sop=sop, ox=ox, oy=oy)

LaTeX text escaping

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

Canvas dimensions

| Format | Width (cm) | Height (cm) | PNG size | | ------------------- | ---------- | ------------ | ----------- | | 16:9 landscape | 25.6 | 14.4 | 1280x720 | | 9:16 vertical | 10.8 | 19.2 | 1080x1920 |

Design tips

• Font sizes: 70-95pt title, 18-24pt subtitle
• Always use \usepackage{lmodern} for large font sizes
• Use \sffamily\bfseries for bold sans-serif
• Gradient backgrounds: \shade[top color=X, bottom color=Y]
• Subtle depth: \fill[black, opacity=0.12] triangle in a corner
• Accent underline: thin \fill rectangle (0.15cm) below title
• 2-3 colors max: bg gradient + 1-2 accent colors
• Escape % as \% and $ as \$ in text nodes