Emitted when the size for the surface needs to be computed, when
it is present.
It will normally be emitted during or after [method@Gdk.Toplevel.present],
depending on the configuration received by the windowing system.
It may also be emitted at any other point in time, in response
to the windowing system spontaneously changing the configuration.
It is the responsibility of the toplevel user to handle this signal
and compute the desired size of the toplevel, given the information
passed via the [struct@Gdk.ToplevelSize] object. Failing to do 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.
It will normally be emitted during or after [method@Gdk.Toplevel.present], depending on the configuration received by the windowing system. It may also be emitted at any other point in time, in response to the windowing system spontaneously changing the configuration.
It is the responsibility of the toplevel user to handle this signal and compute the desired size of the toplevel, given the information passed via the [struct@Gdk.ToplevelSize] object. Failing to do so will result in an arbitrary size being used as a result.