The easiest way how to produce a PDF document from .tgf files (Trivial Graph Format), would be to open/view these files using a suitable program like the yEd and then use the default PDF export/print function to produce a .pdf file.
Convert Trival Graph Format to Adobe Portable document format.
We have found 3 software records in our database eligible for .tgf to .pdf file format conversion.
Microsoft Windows software - convert tgf to pdf on Windows
A utility for creating of high quality diagrams
Convert from tgf file format
The tables with software actions are a good pointer for what a certain program does with various file types and often may give users a good hint how to perform certain file conversion, for example the above-mentioned tgf to pdf. However, it is not perfect and sometimes can show results which are not really usable because of how certain programs work with files and the possible conversion is thus actually not possible at all.
Apple macOS / Mac OS X software - convert tgf to pdf on OS X
A diagraming tool for OS X
Linux/Unix software - convert tgf to pdf on Linux
A Linux version of diagraming tool