Minutes of the GTK team meeting of December 6th, 2012

[Emmanuele Bassi <ebassi gmail com>]

Minutes of the GTK team meeting of December 6th, 2012

- Agenda
  - Frame synchronization (owen)
    - status: https://mail.gnome.org/archives/gtk-devel-list/2012-October/msg00013.html
    - motion event compression:
https://mail.gnome.org/archives/gtk-devel-list/2012-October/msg00014.html
    - a partial TODO:
https://mail.gnome.org/archives/gtk-devel-list/2012-October/msg00015.html
    - open questions:
https://mail.gnome.org/archives/gtk-devel-list/2012-October/msg00016.html
    - branch: http://git.gnome.org/browse/gtk+/log/?h=wip/frame-synchronization
    - current status: patches are pending for review for cogl,
clutter, mutter, and gtk+
    - work is tested and developed against the X11 backend; it
shouldn't actively regress other backends, but there won't be any
synchronization either
    - needs a s/GdkPaintClock/GdkFrameClock/g
    - also needs a documentation pass
    - portability on Quartz: should we be using CoreAnimation to
synchronize painting? is it too high level?
    - are we exposing too much API? is the API too close to the
implementation as to paint ourselves in a corner if we want/need to
change it later?
    - exposed API: GDK <=> GTK interaction; possibly, GtkTimeline to
avoid exposing GdkFrameClock to widgets
    - we can introduce GtkTimeline later, as convenience for animated
widgets, when we have more/better use cases; we can even have it out
of tree in the beginning
    - frame history/timing is API for writing video sinks that are
synchronized with the frame clock in gtk
    - instead of a full Timeline object we could have a "tick
callback" per widget; synchronization is slightly more complicated -
different animations started at the same time would have different
positions
    - may be solved by passing the GdkFrameClock along to the callback
    - animation and layouting is another open question

  - Add <template> and object exporting to GtkBuilder (xjuan)
    - after the Boston Summit, it was decided to split the "composite
template" work in two pieces: 1) new API for GtkBuilder; 2) provide
support in GtkContainer
    - new builder API: https://bugzilla.gnome.org/show_bug.cgi?id=688205
    - newly added method: expose_object(). allows adding a named
instance that can be referenced into a GtkBuilder UI definition
    - newly added XML definition: <template>. allows creating a named
template to apply to an instance.
    - the <template> part generated a bit of confusion
    - having examples in gtk-demo would help evaluating the API
    - changing <template> to <external-object> would help in remove
some of the confusion; also, using <external-object> for declaring
slots to be filled
    - possible extension of the XML definition: define custom types
directly inside the UI definition
    - the plan is: review and land expose_object(); rename the current
<template> to <external-object>; discuss having custom subclasses
defined directly in the GtkBuilder definition

- Next meeting: Tuesday, January 8th, 2013 (tentative)

ciao,
 Emmanuele.

--
W: http://www.emmanuelebassi.name
B: http://blogs.gnome.org/ebassi/