Re: Viewing PDFs. (Was: Happy new Sun)

[Deri]

On Saturday, 24 December 2022 09:06:07 GMT Ralph Corderoy wrote:
> Hi Deri,
> 
> > You may need to open the outline pane on the left, which acts like a
> > table of contents.
> 
> Is it mandatory that a PDF viewer must supply this mechanism to be
> worthy of the name?  Off-hand, I don't recall mupdf(1) or llpp(1) having
> an option or keystroke to show it.

Hi Ralph,

A lot of the PDF spec is optional, I don't think many viewers support things 
like flash and javascript (for very good reasons!). It does not make them 
lesser viewers. I don't have llpp so I can't comment, but it does seem like 
mupdf does not support it. There is an optional entry that can be added to the 
pdf:-

/PageMode /UseOutlines.

Which is intended to tell the viewer to open the outline panel, as an 
experiment I added it to the pdf but mupdf was the same. I don't normally add 
this command since I think its up to the user to decide whether they want the 
clutter of a side panel or not. In fact, having a clean interface may be a 
deliberate choice for mupdf, and makes pdf viewing consistent with all the 
other file types it supports.

These viewers support the outline panel:-

okular
evince
qpdfviewer
xpdf
firefox
chromium-browser

So there are a fair few which will show outlines. I discovered that acroread 
under a windows 10 VM has significant issues with the book, the font glyphs 
are all wrong! I suspect it is due to embedding Google's Tinos font (which is 
huge) to provide the glyphs for the iso-8859 pages, since if I run the pdf 
through ghostscript to subset all the fonts it then works. I must get around 
to subsetting the fonts myself, I've written most of the code to decrypt/
encrypt the type 1 fonts, so I could strip out unused glyphs, I've just got to 
port it into gropdf.

Cheers

Deri