Traditionally, WMs unmap windows when minimizing them, and map them
when restoring them or wanting to show them for other reasons, like
upon creation.
However, as metacity morphed into mutter, we optionally chose to keep
windows mapped for the lifetime of the window under the user option
"live-window-previews", which makes the code keep windows mapped so it
can show window preview for minimized windows in other places, like
Alt-Tab and Expose.
I removed this preference two years ago mechanically, by removing all
the if statements, but never went through and cleaned up the code so
that windows are simply mapped for the lifetime of the window -- the
"architecture" of the old code that maps and unmaps on show/hide was
still there.
Remove this now.
The one case we still need to be careful of is shaded windows, in which
we do still unmap the client window. In the future, we might want to
show previews of shaded windows in the overview and Alt-Tab. In that
we'd also keep shaded windows mapped, and could remove all unmap logic,
but we'd need a more complex method of showing the shaded titlebar, such
as using a different actor.
At the same time, simplify the compositor interface by removing
meta_compositor_window_[un]mapped API, and instead adding/removing the
window on-demand.
https://bugzilla.gnome.org/show_bug.cgi?id=720631
Instead of hardcoded knowledge of certain classes in MetaWindowGroup,
create a generic interface that all actors can implement to get parts of
their regions culled out during redraw, without needing any special
knowledge of how to handle a specific actor.
The names now are a bit suspect. MetaBackgroundGroup is a simple
MetaCullable that knows how to cull children, and MetaWindowGroup is the
"toplevel" cullable that computes the initial two regions. A future
cleanup here could be to merge MetaWindowGroup / MetaBackgroundGroup so
that we only have a generic MetaSimpleCullable, and move the "toplevel"
cullability to be a MetaCullableToplevel.
https://bugzilla.gnome.org/show_bug.cgi?id=714706
For clarity, rename meta_window_get_outer_rect() to match terminology
we use elsewhere. The old function is left as a deprecated
compatibility wrapper.
There are extensive places in the code where we convert between the client
rectangle and the frame rectangle. Instead of manually doing it use
new helper functions on MetaWindow and the existing meta_window_get_outer_rect().
This fixes a number of bugs where the computation was being done incorrectly,
most of these bugs are with the recently added custom frame extents, but
some relate to invisible borders or even simply to confusion between the
window and frame rectangle.
Switch the placement code to place the frame rectangle rather
than the client window - this simplifies things considerably.
https://bugzilla.gnome.org/show_bug.cgi?id=707194
