Re: Emacs, QT and Cairo

[Jan Djärv]

David Engster skrev 2010-07-14 11.41:

> Yes, one could probably create buttons and stuff like that with SVG. But
> the way images are handled in Emacs make this very limited. I'm not even
> talking about eye candy here, but very basic things. For example,
> drawing a faint line at column 80, like this:
>
> http://blogs.sun.com/tor/resource/formatting-before.png
>
> I think it is currently not possible to do stuff like this?

I don't think the display engine is up to the job for that.  AFAIK, it lacks 
the ability to put stuff at absolute coordinates, like your line that always 
should be a column 80.  It is more text oriented and text flows one character 
after another.  Also, unless I'm mistaken, it doesn't handle stacking, i.e. 
shall the line go over or under text?

Making a lisp function that draws lines is not that hard.  Handling redisplay 
of the line when something changes is the hard part.

        Jan D.