Document consequences of not embedding fonts

[johnblommers]

It is clear from the mdpdf description that font embedding is not done in order to keep the PDF file size small. Only two fonts are included, Helvetica (four variants) and Courier (two variants). These are common fonts, and it's expected they are present on every operating system. All this is reasonable.

Believe it or not, PopOS 22.04 does not include a font called Courier or Courier-Bold. Who knew? The consequences of this are that Document Viewer displays a raft of the message "some font thing failed" in the console, and any code in the PDF that results from the Markdown syntax like sometext isn't displayed, only empty space suggests something is missing from the PDF display. Note that when one views the PDF file properties in Document Viewer it plainly notes that the six fonts used by mdpdf are not embedded.

Now on Ubuntu 25.10 the Courier font is pre-installed and the PDF produced looks fantastic.

Consider adding an abundance of documentation stressing the importance of the system having these six fonts installed:

• Helvetica
• Helvetica-Bold
• Helvetica-Oblique
• Helvetica-BoldOblique
• Courier
• Courier-Bold

[schicho]

Thank you for raising this issue. I didn't expect this to occur.

This seems to be an issue with PopOS's PDF viewer.

PDF viewers are (mostly) expected to substitute fonts. Ubuntu does not have Helvetica installed either. They get silently substituted with an appropriate font.

Firefox and Chrome also have no issues substituting the font for me.

Wikipedia (https://en.wikipedia.org/wiki/PDF#Text) states: "These fonts, or suitable substitute fonts with the same metrics, should be available in most PDF readers, but they are not guaranteed to be available in the reader, and may only display correctly if the system has them installed.[32] Fonts may be substituted if they are not embedded in a PDF."

Consider adding an abundance of documentation stressing the importance of the system having these six fonts installed

No. There is no need for an abundance of anything. This is a small C tool, it's far from perfect, and it works for 90% of use cases.

Maybe consider raising an issue with whatever PopOS uses as PDF viewer.

This is now a known issue, thanks for mentioning it. I'll leave this open as a won't-fix issue.

[johnblommers]

I did not expect this to be an issue either, but the longer we live the more we learn.

This issue should be more than enough documentation. I'm glad I posted this issue because I learned something.

Update: Okular (that which installs on Ubuntu 25.10) also does not display text that's Courier but does not inform the user either.