This is a way to query the damaged area of the backbuffer.
The GL renderer uses this to compute the extents of that damage region
(computed via buffer age) and use them to minimize the area to redraw.
This changes the semantics of GL rendering to "When calling
gdk_window_begin_frame() with a GL context, the area by
gdk_gl_context_get_damage() needs to be redrawn and every other pixel of
the backbuffer is guaranteed to be correct.
After gdk_window_end_frame() on a GL-drawn window, the whole backbuffer
must be correct.
We can always glXBufferSwap() now because of this.
The functions gdk_pixbuf_get_from_window() and
gdk_cairo_set_source_window() are unreliable and depend on the windowing
system (they work great on X11 and Win32, less so on Quartz and Wayland).
With the switch to new drawing API and OpenGL, we can definitely no
longer support a generic way to snapshot windows.
People should either write windowsystem-specific code or draw their
widgets directly - like with gtk_widget_draw() - if they need to get a
rendering.
Switch code to use gdk_display_is_composited() instead.
The new code also doesn't use a vfunc to query the property but rather
requires the backend to call set_composited()/set_rgba() to change the
value.
Also add properties for those two properties.
The first property is equivalent to checking if an RGBA visual exists,
the 2nd is equivalent to gdk_screen_is_composited().
These complicate a lot of GdkWindow internals to implement features
that not a lot of apps use, and will be better achieved using gsk.
So, we just drop it all.
This is an attempt to get rid of gdk_window_new() for more specific use
cases. These 2 are for client-side windows - regular ones and input-only
ones resepectively.
So far all those functions just call into gdk_window_new().
The update tracking code was ugly and using deprecated drawing APIs. It
was also in the wrong place.
So instead of trying to keep it working, I'll remove it. We need to find
a better way to put it and make it work there.
... and gdk_screen_get_window_stack().
Those functions were originally added in
5afb4f0f11 but do not seem to be used as
they are not implemented anywhere but in X.
As GDK is not meant to fulfill window management functionality I'm going
to remove these functions without replacements.
... and gdk_screen_get_width_mm() and gdk_screen_get_height_mm() and
the shortcut counterparts that call these functions on the default
screen.
Modern display servers don't provide an ability to query the size of a
screen or display so we shouldn't allow that either.
