This ensures that two widgets sharing the same theme node won't trample
on each other's prerendered materials if the actors are of different
sizes. This also tries to be very careful to share as much as possible
during a transition.
This has the side effect that if a widget changes state a bunch of times,
we won't cache every state. Since we expect that state changes are
infrequent and that most cases we'll be able to use the texture cache
to do most of the heavy lifting, this cost is much more insignificant
than rendering a number of different actors with the same theme node
and different sizes.
https://bugzilla.gnome.org/show_bug.cgi?id=697274
StWidget reports a paint volume large enough to paint the current
theme node. As CSS transitions also paint the previous theme node,
the reported paint volume may be incorrect, resulting in screen
artifacts when painting outside the reported volume.
Add st_theme_node_transition_get_paint_box() to calculate an allocation
large enough to paint both theme nodes, and use it to report the correct
paint volume during transitions.
https://bugzilla.gnome.org/show_bug.cgi?id=640085
* Make sure all source files have a LGPL copyright header, and standardize
non-standard variations of the header to a common form.
* Check and update all copyright notices.
* Remove 'Written By:' lines. They are universally incomplete and
typically indicate only who started a particular file.
https://bugzilla.gnome.org/show_bug.cgi?id=634550
