needs-update

Called by the buffer to request a refresh to its displayed representation. When the administrator decides that the displayed should be refreshed, it calls the buffer's refreshmethod.

• (send a-wx:media-admin needs-update localx localy w h) -> void
      localx : inexact real
      localy : inexact real
      w : inexact real
      h : inexact real

  The localx, localy, w, and h arguments specify a region of the buffer to be updated (in buffer coordinates).