Re: advice on implementing "elastic tabstops" for GTK+ 2.x?

["Nick Gravgaard" <me nickgravgaard com>]

On 15/10/06, Owen Taylor <otaylor redhat com> wrote:
> On Sun, 2006-10-15 at 18:07 +0200, Nick Gravgaard wrote:
> > Hi all,
> >
> > I would like to implement an idea I call "elastic tabstops" (see
> > nickgravgaard.com/elastictabstops/) for GTK+ 2.x. Could someone advise
> > me on whether support for this should be added to an exisiting widget
> > (GtkTextView?), or if another approach should be used?
>
> Because the effect is non-local - the contents of one paragraph effect
> the drawing (and line wrapping?) of previous/following paragraphs, you'd
> certainly have to change the GtkTextView code to make GtkTextView show
> that effect. A GtkTextView uses a PangoLayout per paragraph.
>
> (Nobody uses GtkTextView for editing source code directly, but the
> GtkSourceView subclass is used for that extensively. That's a separate
> project from GTK+.)
>
> If you also wanted to get the effect for multi-line GtkLabels then you'd
> have to also implement support for it inside Pango, since a GtkLabel
> uses a single PangoLayout with multiple paragraphs in it.
>
> GtkTextView and GtkLabel are the only GTK+ widgets that show multiple
> lines of text.
>
> For both GtkTextView and PangoLayout I think you'd find the job a bit
> challenging. (Think days or weeks, not hours.) There is a lot of
> existing complexity in both of them you'd have to integrate with. But
> possible? I don't see why not.

Thanks for the reply.

Ideally I'd like to write the code in a modular way so that it can be
easily added to any GTK multi-line text widget, but I'm still at the
exploratory stage so I don't know if such an approach is possible. It
would be great if I could write something that could be used by
GtkTextView, GtkSourceView and whatever widget Vim uses...