Interface Toplevel.ComputeSizeCallback

All Superinterfaces:
FunctionPointer
Enclosing interface:
Toplevel
Functional Interface:
This is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference.
@FunctionalInterface public static interface Toplevel.ComputeSizeCallback extends FunctionPointer

Functional interface declaration of the ComputeSizeCallback callback.

See Also:

  • Method Details

    • run

      void run(@Nullable ToplevelSize size)

      Emitted when the size for the surface needs to be computed, when it is present.

      This signal will normally be emitted during or after a call to Toplevel.present(ToplevelLayout), 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 of the toplevel surface.

      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 Gdk.ToplevelSize object. Failing to do so will result in an arbitrary size being used as a result.

    • upcall

      default void upcall(MemorySegment sourceToplevel, MemorySegment size)
      The upcall method is called from native code. The parameters are marshaled and run(ToplevelSize) is executed.

    • toCallback

      default MemorySegment toCallback(Arena arena)
      Creates a native function pointer to the upcall(MemorySegment, MemorySegment) method.
      Specified by:
      toCallback in interface FunctionPointer
      Parameters:
      arena - the arena in which the function pointer is allocated
      Returns:
      the native function pointer