PDF Font Inspector

Inspect embedded fonts in PDF files — browse font subsets, view glyphs, check character coverage.

Features

• Font list — all fonts embedded in the PDF shown as tabs; each tab shows the font name and glyph count
• Embedded Glyphs pane — renders every glyph using the actual font outlines extracted from the PDF
• Character coverage pane — visual grid showing which characters are present (green) or missing (red)

Requirements

# Install dependencies on Debian/Ubuntu:
sudo apt install python3-gi gir1.2-gtk-3.0 python3-cairo gir1.2-pango-1.0
pip install pymupdf fonttools

• Python 3.12+
• GTK 3 + GObject introspection (python3-gi, gir1.2-gtk-3.0)
• PyMuPDF (pymupdf)
• fontTools (fonttools)
• Cairo + PangoCairo (python3-cairo, gir1.2-pango-1.0)

Usage

# Open the app
python3 pdf_fonts.py
# Open the app with file.pdf
python3 pdf_fonts.py file.pdf

Open a pdf via button Open PDF or drop it onto the app. Click on font tabs to view a font's subset glyphs and its character coverage.

How it works

PDF fonts are subsets that contain glyph outlines but no unicode mapping — that lives separately in the PDF as a ToUnicode CMap stream. This tool:

• Parses this stream to build a glyph-to-codepoint map
• Extracts raw font bytes from the PDF using PyMuPDF
• Loads these bytes into fontTools to get glyph outlines
• Renders these outlines directly with Cairo