pptx-pdf-font-fix
// Fix PowerPoint font embedding issues in PDF export by patching text transparency in PPTX files. Use when a user has a PPTX file where exported PDFs show wrong/default fonts instead of the intended downloaded/custom fonts, even with font embedding enabled. Works by applying minimal (1%) transparency
PPT Font Fix
Problem
PowerPoint's "Export to PDF" can fail to embed downloaded/custom fonts, substituting built-in defaults, even when:
- Fonts are properly installed and embeddable
- "Embed fonts in the file" is checked in PowerPoint options
Workaround
Applying a tiny transparency (1%) to text with 0% transparency forces PowerPoint to correctly embed fonts in PDF output. This is visually imperceptible but changes how PowerPoint processes the font during export.
Usage
python3 scripts/fix_font_transparency.py input.pptx [output.pptx] [--transparency 1]
Options
output-- Output PPTX path (default:input_fixed.pptx)--transparency, -t-- Transparency % to apply (default: 1)
Behavior
- Only patches text runs that are fully opaque (0% transparency)
- Leaves text that already has any transparency untouched
- Safe to run multiple times
- Only modifies slide XML (
ppt/slides/slideN.xml), not layouts/masters
Workflow
- Receive PPTX file from user
- Run the fix script:
python3 scripts/fix_font_transparency.py input.pptx - Return the patched PPTX to the user
- User opens patched file in PowerPoint and exports to PDF -- fonts now embed correctly
Note
PDF export must be done from PowerPoint desktop. Server-side converters (LibreOffice, Graph API) do not reproduce the same font embedding behavior.