# HG changeset patch
# User Rik <rik@octave.org>
# Date 1429805650 25200
# Node ID f46f6d90665485510f87118eadb6ee69f31941c9
# Parent  144498565de97c557e89224d0fb6daf57786f1fc
Avoid unnecessarily calling graphics callbacks in FLTK.

* __init_fltk__.cc: Replace all tests for callback functions which use
is_defined() (that is always true as long as the octave-value exists) with
! is_empty() which is a real test of whether there is a function handle to
call.

diff -r 144498565de9 -r f46f6d906654 libinterp/dldfcn/__init_fltk__.cc
--- a/libinterp/dldfcn/__init_fltk__.cc	Thu Apr 23 08:38:49 2015 -0700
+++ b/libinterp/dldfcn/__init_fltk__.cc	Thu Apr 23 09:14:10 2015 -0700
@@ -1505,7 +1505,7 @@
                   evt = format_key_event (e_key, e_text, e_state);
                 }
 
-              if (fp.get_keyreleasefcn ().is_defined ()
+              if (! fp.get_keyreleasefcn ().is_empty ()
                   && (evt.contents ("Key").length () > 0))
                 fp.execute_keyreleasefcn (evt);
               return 1;
@@ -1552,7 +1552,7 @@
 
               // Ensure windowbuttondownfcn is called after currentpoint
               // is updated but before calling buttondownfcn.
-              if (fp.get_windowbuttondownfcn ().is_defined ())
+              if (! fp.get_windowbuttondownfcn ().is_empty ())
                 fp.execute_windowbuttondownfcn (Fl::event_button ());
 
               if (gh.ok ())
@@ -1567,18 +1567,18 @@
                   fp.set_currentobject (ax_obj.get_handle ().value ());
 
                   base_properties& props = ax_obj.get_properties ();
-                  if (props.get_buttondownfcn ().is_defined ())
+                  if (! props.get_buttondownfcn ().is_empty ())
                     props.execute_buttondownfcn (Fl::event_button ());
 
                   return 1;
                 }
-              else if (fp.get_buttondownfcn ().is_defined ())
+              else if (! fp.get_buttondownfcn ().is_empty ())
                 fp.execute_buttondownfcn (Fl::event_button ());
 
               break;
 
             case FL_DRAG:
-              if (fp.get_windowbuttonmotionfcn ().is_defined ())
+              if (! fp.get_windowbuttonmotionfcn ().is_empty ())
                 {
                   set_currentpoint (Fl::event_x (), Fl::event_y () - menu_dy ());
                   fp.execute_windowbuttonmotionfcn ();
@@ -1692,7 +1692,7 @@
               }
 
             case FL_RELEASE:
-              if (fp.get_windowbuttonupfcn ().is_defined ())
+              if (! fp.get_windowbuttonupfcn ().is_empty ())
                 {
                   set_currentpoint (Fl::event_x (), Fl::event_y () - menu_dy ());
                   fp.execute_windowbuttonupfcn ();