pdf: utilize bookmarks and heading for navigation

[izorba]

Thorium can open and read a pdf file, but it does not utilize bookmarks and headings of the tagged pdf file for navigation functionality.

[panaC]

In Thorium the support of the PDF doesn't include the table of content navigation but include bookmarks feature.

You can click on the bookmark button, the color become gray

and you can find the bookmark in navigation menu

I'm closing the issue feel free to reopen it. 😁

[panaC]

@llemeurfr Perhaps we should open a discussion about table of content navigation in PDF ?

[danielweck]

@panaC I think @izorba is referring to accessible "tagged PDFs":
https://helpx.adobe.com/uk/acrobat/using/creating-accessible-pdfs.html
...so I think we should keep this issue opened as a "feature request", and maybe ultimately decide not to implement support for tagged PDF functionality, but at least document this decision properly :)

[danielweck]

Note that PDF.js (the rendering library used internally by Thorium to parse and render PDF files) claims to handle semantic markup in accessible PDF, but it is unclear to me that this includes support for all the features expected in "tagged PDFs", such as bookmarks and TOC:
mozilla/pdf.js#13171
mozilla/pdf.js#6269

[panaC]

Thank Daniel, I did not understand.

[danielweck]

Also see these discussions:

• https://bugzilla.mozilla.org/show_bug.cgi?id=1705139
• https://bugzilla.mozilla.org/show_bug.cgi?id=727819
• https://bugzilla.mozilla.org/show_bug.cgi?id=861157