It is good practice for (floating) window managers to respect explicit
position hints from clients (as long as the window wouldn't end up
off-screen etc.).
Before commit 13d3afa56e, GTK had a flag for setting the PPosition hint,
but now does so unconditionally. However the real intention is to *not*
request a fixed position, so don't do that.
Now that we have the display's context to hook into, we can use it to
construct other GL contexts and don't need a GdkSurface vfunc anymore.
This has the added benefit that backends can have different GdkGLContext
classes on the display and get new GLContexts generated from them, so
we get multiple GL backend support per GDK backend for free.
I originally wanted to make this a vfunc on GdkGLContextClass, but
it turns out all the abckends would just call g_object_new() anyway.
Avoids having to use private data, though the benefit is somewhat
limited as we still have to put the destructor in the egl code and can't
just put it in gdk_surface_x11_finalize().
We were calling _gdk_surface_update_size() every frame, even if the
window size didn't change. This would cause us to discard all cached
buffers and redraw the whole screen.
This was BAD.
On x11 toplevel layout is not created before toplevel
is presented, but GTK tries to update it on idle
which leads to a crash due to accessing property
of undefined object. Treat soon to be created layout
as a layout with default values upon creation (resizable).
When being fullscreen, and wanting to unfullscreen but not caring about
whether to go unmaximized or maximized (as this information is lost), if
the GdkToplevelLayout represents the full intended state, we won't be
able to do the right thing.
To avoid this issue, make the GdkToplevelLayout API intend based, where
if one e.g. doesn't call gdk_toplevel_set_maximized() with anything, the
backend will not attempt to change the maximized state.
This means we can also remove the old 'initially_maximized' and
'initially_fullscreen' fields from the private GtkWindow struct, as we
only deal with intents now.
It was used by all surfaces to track 'is-mapped', but still part of the
GdkToplevelState, and is now replaced with a separate boolean in the
GdkSurface structure.
It also caused issues when a widget was unmapped, and due to that
unmapped a popover which hid its corresponding surface. When this
surface was hidden, it emitted a state change event, which would then go
back into GTK and queue a resize on popover widget, which would travel
back down to the widget that was originally unmapped, causing confusino
when doing future allocations.
To summarize, one should not hide widgets during allocation, and to
avoid this, make this new is-mapped boolean asynchronous when hiding a
surface, meaning the notification event for the changed mapped state
will be emitted in an idle callback. This avoids the above described
reentry issue.
This will sometimes mean a frame is skipped if a resize was requested
during the update phase of the frame dispatch. Not doing so can cause
trying to allocate a window smaller than the minimum size of the widget.
If compute_size() returns TRUE, the layout will not be propagated to
GTK. This will be used by the X11 backend to queue asynchronous resizes
that shouldn't yet allocate in GTK.
This removes the gdk_surface_set_shadow_width() function and related
vfuncs. The point here is that the shadow width and surface size can now
be communicated to GDK atomically, meaning it's possible to avoid
intermediate stages where the surface size includes the shadow, but
without the shadow width set, or the other way around.
This follows the trail of the Wayland backend in that GdkSurface changes
happen during the layout phase, and that a GDK_CONFIGURE no longer being
used to communicate the size changes of a surface; this now also uses
the layout signal on the GdkSurface.
The plan is to concencrate size computations as part of the frame clock
dispatch, meaning we shouldn't do it synchronously in the present()
function.
Still, in Wayland, and maybe elsewhere, it is done in the present()
function, e.g. when no state change was made, but this will eventually
be changed.
GTK will not up front know how to correctly calculate a size, since it
will not be able to reliably predict the constraints that may exist
where it will be mapped.
Thus, to handle this, calculate the size of the toplevel by having GDK
emitting a signal called 'compute-size' that will contain information
needed for computing a toplevel window size.
This signal may be emitted at any time, e.g. during
gdk_toplevel_present(), or spontaneously if constraints change.
This also drops the max size from the toplevel layout, while moving the
min size from the toplevel layout struct to the struct passed via the
signal,
This needs changes to a test case where we make sure we process
GDK_CONFIGURE etc, which means we also needs to show the window and
process all pending events in the test-focus-chain test case.
