Validating Fonts when Using Telerik Document Processing
Environment
| Version | Product | Author |
|---|---|---|
| 2025.2.520 | Telerik Document Processing | Desislava Yordanova |
Description
When exporting a document to PDF format using the Telerik Document Processing Librararies, content issues may occur due to incomplete or corrupted font files. These issues can arise if the font file is incomplete, corrupted, or missing required font tables. This results in missing or improperly rendered text in the exported PDF.
This knowledge base article gives some tips and tricks how to validate fonts used in Telerik Document Processing and what tools can check for font file's integrity.
Solution
To ensure a font file is complete and compatible with Telerik Document Processing, follow these steps:
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Open the Font in a Font Viewer
Double-click the TTF file to open it in the system font viewer. Inspect whether all expected characters display correctly and ensure no error messages appear.
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Test the Font in Other Applications
Install the font on your system and use it in applications like Word or Notepad. Verify that all characters render correctly.
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Compare File Size and Metadata
Compare the file size and properties of the font with an official or known-good version. Noticeable differences can indicate corruption or missing data.
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Use Font Validation Tools
Validate the font file with tools like:-
FontForge
-
Microsoft Font Validator
These tools check for missing tables, corrupt glyphs, and other font-related issues.
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FontForge
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Check Required Styles
Verify that all required styles (Regular, Bold, Italic, etc.) are available if your document uses them. Missing styles can cause fallback or rendering issues.
Recommendations
- Validate fonts from third-party sources before integrating them.
- Request official font packages or sources for reliable compatibility.
- Replace problematic font files with known-good versions to resolve rendering issues.
- You can utilize a FontsProvider implementation to identify all fonts and styles used in the document. Thus, you can log missing or problematic fonts during testing for early detection.