If both events contain X/Y information, the center of both coordinates will be returned in @x and @y.
first #GdkEvent
second #GdkEvent
return location for the X coordinate of the center
return location for the Y coordinate of the center
%TRUE if the center could be calculated.
3.0
See Implementation
If both events contain X/Y information, the center of both coordinates will be returned in @x and @y.