[Texmacs-dev] Pdf marks and Re: adding pdf hyperlink support

[Joris van der Hoeven]

Dear Sam,

On Tue, Jun 28, 2011 at 06:15:17PM +0100, Sam Liddicott wrote:
> I'm determined to add PDF hyperlink support to texmacs.

Thanks for your work on this issue. I was indeed surprised to
discover that various links were added to a Pdf export.

There are a few quirks though: the locus_boxes are only used
for "inactive non line-breakable markup". For instance,
hyperlinks do not work with the current implementation.

If you have some time, then this whould be the way around this:
instead of (or in addition to?) using the locus_boxes in order to
determine what should be linked to what, you should scan all subtrees
of the document tree, and determine whether there are links attached
to them. For instance, look at the 'link-active-upwards' scheme
routine (even though scanning should be fast and written in C++).
>From the subtrees to which we attached links, you should next
determine the corresponding bounding boxes (or regions);
see edit_interface_rep::update_active_loci for how this works.

Another related question concerns alpha-trasparency;
I tried to add this to the last version 1.0.7.11
(enable using Debug -> Experimental -> Alpha transparency,
after which you may try to draw a graphics using alpha
transparency, or try Insert -> Presentation tag -> Greyed,
on top of some non uniform background).

However, contrary to linking info, it seems that ghostscript
does not support this extension. I would be interested to
know whether my code does work with Acrobat distiller.
It would be nice if someone could incite the ghostscript
people to correctly implement alpha transparency Pdf marks
when converting from Postscript to Pdf. It seems that they
already did most of the work anyway.

Best, --Joris