Emitted when the size for the surface needs to be computed, when it is
present.
This signal will normally be emitted during the native surface layout
cycle when the surface size needs to be recomputed.
It is the responsibility of the drag surface user to handle this signal
and compute the desired size of the surface, storing the computed size
in the Gdk.DragSurfaceSize object that is passed to the signal
handler, using Gdk.DragSurfaceSize.set_size.
Failing to set a size so will result in an arbitrary size being used as
a result.
Emitted when the size for the surface needs to be computed, when it is present.
This signal will normally be emitted during the native surface layout cycle when the surface size needs to be recomputed.
It is the responsibility of the drag surface user to handle this signal and compute the desired size of the surface, storing the computed size in the Gdk.DragSurfaceSize object that is passed to the signal handler, using Gdk.DragSurfaceSize.set_size.
Failing to set a size so will result in an arbitrary size being used as a result.