Future of GtkTooltips

[Christian Neumair <chris gnome-de org>]

Problems - in short - with the current tooltip system:

- Not flexible enough (only plain text can be set)
- Unable to set popup location
- Exposes too many internals (GtkTooltipsData, tip_text, tip_private)
  without getters/setters

Proposed resultions:

Flexibility:
- Use either GtkTextBuffer for powerful tooltips, might be overhead
- Or use at least PangoMarkup or PangoLayout

Location:
- Model an optional function similar to GtkMenuPositionFunc

Internals:
All attempts to work around internal exposure MUST fail. A clean
reorganization would include redesigning the tooltip-widget relation.
To be honest, I'm not sure whether it is useful to group tooltips
together in GtkTooltips at all. Is this used? Aren't tooltips usually
describing widget's functions independently from other widgets? Are
people using multi-functional widget groups with multiple GtkTooltips
assigned that are enabled/disabled when needed?
Wouldn't it be more simple to create one GtkTooltip (which would be a
new type) per widget, passing a text layout and an optional position
function to the tooltip and assign it somehow to the widget, maybe
through a property? If people want multi-functional widgets, wouldn't it
be simpler to optionally associate a widget state with a tooltip?

It would be great to get some application author feedback, I'm really
eager to redesign tooltips for GTK+ 2.8 :), this task has been
outstanding for a long time.

-- 
Christian Neumair <chris gnome-de org>