CSS letter-spacing adds extra spaces between letters in PDF

[tsaquet]

Hello,

Marp is a great tool, thank you 👍

I use marp-cli to generate HTML and PDF, I have a theme based on the provided "uncover" theme.

Some people using my PDF files told me about some problems, they are extra spaces between letters, which causes two issues :

• impossible to use the research tool in the PDF
• copy/paste is quite unsable too

I spent quite a lot of time to investigate to find out that :

• Most of HTML/CSS -> PDF converters have that problem
• It is caused by the "letter-spacing" property in CSS

I added a specific "letter-spacing: unset;" for my PDF generations, it solves the problems above but the result without the spacing is not so good, I would like to keep the spacing without the drawbacks. Til now, I could not find a solution.

Does anyone see a better solution to that problem ?

Thank you !

[yhatt]

Could you share minimum reproducible Markdown and PDF? I tried using uncover theme as is, and the exported PDF that was opened by Adobe Acrobat could copy the text correctly.

Thanks to Chromium, Marp CLI can generate the tagged PDF, that has included extra metadata about the structure of a document such as text data (#269: https://blog.chromium.org/2020/07/using-chrome-to-generate-more.html). If a using PDF viewer could recognize them, visible spaces in the PDF page should not effect to the actual text data. And if not, the quality of text recognization (OCR) may depend on PDF viewers.

Helpful article: What's so hard about PDF text extraction? (archive)

[tsaquet]

I'll provide a minimal example dureing the week, thank you :)

[yhatt]

Close for housekeeping. 🧹 This is probably depending on PDF viewer to read, and Marp cannot do anything for that.