Re: Emacs and Gnome Canvas

[Eli Zaretskii <eliz@gnu.org>]

> From: Óscar Fuentes <ofv@wanadoo.es>
> Date: Thu, 15 Jul 2010 23:27:14 +0200
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> >> I would use Qt, hence C++, not being shy about using advanced language
> >> features if necessary. That is for getting a working system as soon as
> >> possible.
> >
> > C++ is not the fastest language to get a job done.
> 
> That's very true. Unfortunately, AFAIK there is no Free high quality
> cross platform GUI for Lisp :-)

If we are talking a throw-away project, why not Python?

> > Plus, you'll have unrelated job on your hands of making Emacs
> > C++-compliant, as discussed in another thread.
> 
> Only the Emacs header files that the display engine needs must be
> acceptable by g++. The .c files would be compiled by gcc as usual.

I meant link-time and run-time compatibility, not syntactic
compatibility.

> Apart from reading all the source code, I hope that it is possible to
> look into just a few header files for learning the interface of the
> display engine.

Unfortunately, I'm not sure.  The header is dispextern.h, but if you
read through it, you will find that it mixes internal details of the
current implementation with external APIs in a way that discerning one
from the other is not trivial.

I would suggest instead to study the basic display iterator (defined
as `struct it') and the iteration process, implemented in two parts:
get_next_display_element and set_iterator_to_next.  These two and the
subroutines of get_next_display_element (next_element_from_*) are
where you see all the top-level features that the current display
engine implements; reading the relevant parts of the ELisp manual will
complete the picture regarding each one of the features.