The attached HTML code when parsed through PrinceXML, generates a PDF that looks like this:
, where there are small gaps between the vertical lines in the columns. The HTML code contains MathML code, and when I tried generating a PDF/image with some other MathML parsing libraries, they render the table correctly.

Any suggestions?

1. math.html‎ 0.9 kB ‎
   HTML file when parse through PrinceXML

In your code, you have:

<mtable framespacing="0.0em 0.5ex">

Prince honors the 'framespacing' attribute and therefore adds gaps. If you do not want these, you can set framespacing to zero.

Edited 20 Jan 2021 by howcome

Prince ought to extend the row and column lines out to the frame, though, instead of leaving gaps. (probably)

Edited 21 Jan 2021 by wangp

@howcome: changing the framespacing attribute to 0.0 has made no difference, there are still gaps as before.

Attached is a sample with framespacing set to zero, along with the resulting PDF file. I do not see any gaps in the PDF file. Could you try processing my file in your installation?

1. math.html‎ 0.9 kB ‎
   math.html
2. math.pdf‎ 23.1 kB ‎
   math.pdf

Edited 21 Jan 2021 by howcome

Yes this works, thanks!