PDF Fonts & Font Subsets
Font handling is the most complex graphical component of the PDF specification. A PDF can rely on the OS to provide standard fonts (like Arial or Times), embed the entire TrueType file directly into the PDF, or mathematically subset only the specific glyphs used in the text.
These files isolate font extraction challenges. They test your system's ability to render custom embedded typefaces, handle the lack of `/ToUnicode` mapping in extreme subsets, and fall back to system defaults gracefully when fonts are missing.
Missing fonts
A file that explicitly calls for obscure, non-standard fonts without embedding them. Designed to aggressively test parser font-fallback heuristics.
Embedded fonts
A file where the entire font file is embedded in the binary stream, ensuring pixel-perfect rendering regardless of the host OS.
Font subsets
A highly optimized file where only the used glyphs are embedded. Tests subset-mapping logic during text extraction.
Multiple fonts
A single document mixing serif, sans-serif, and monospace embedded fonts to stress-test rendering engine caching limits.
Frequently Asked Questions
Use Cases
- Validating text-extraction tools against extreme font subsets (where character codes do not align with standard ASCII).
- Testing font-fallback rendering mechanisms (like PDF.js) when a document requests a font that does not exist on the client OS.
- Ensuring print-spoolers correctly extract and load embedded TrueType streams before spooling to a physical printer.