This function is given a barely setup GdkEvent, so the GdkDevice field
is still unset, causing warnings and misbehaviors when the position
is queried for it.
Given that the wintab GTK+ code seems to rely somewhat hard on the wintab
device managing the pointer cursor, query the pointer position from the
pointer itself.
https://bugzilla.gnome.org/show_bug.cgi?id=743330
The window used NULL as a parent window, which defaults internally to
using the root window of the default screen. But at the time wintab is
initialized, there is no default display/screen yet.
Fix this by retrieving this information from the given GdkDeviceManager,
so we don't have to wait for the display to be in place before
initialization.
https://bugzilla.gnome.org/show_bug.cgi?id=743330
We now have a proper MASTER/SLAVE input device split, where
the masters are virtual core input devices and we add fake hw
slave devices for the system pointer and real slave devices for
wintab devices.
We also set the proper source_device on the events so you can
tell which device sent it and properly decode the axis info.
There are sure regressions but basic stuff seems to be working
again after all the API breakage done with comments like
"Win32 and Quartz need to be ported still."
This function makes a better replacement for
gdk_display_get_core_pointer(), wherever it might yet be needed, for
XI2 resorts to XIGetClientPointer(), for the others return the only
core pointer.
https://bugzilla.gnome.org/show_bug.cgi?id=621685
