Navigation in menubar: wrap around when using arrow past end or start of menubar.

See "Menu navigation in FLTK is different from Ubuntu X11 navigation" in fltk.general.
Menubar wrapping is what macOS and gnome applications do.

1 files changed, 13 insertions, 8 deletions

diff --git a/src/Fl_Menu.cxx b/src/Fl_Menu.cxx
index ed362a921..8d7e7a4c5 100644
--- a/src/Fl_Menu.cxx
+++ b/src/Fl_Menu.cxx
@@ -694,14 +694,17 @@ static void setitem(int m, int n) {
 
 static int forward(int menu) { // go to next item in menu menu if possible
   menustate &pp = *p;
-  // Fl_Menu_Button can generate menu=-1. This line fixes it and selectes the first item.
+  // Fl_Menu_Button can generate menu=-1. This line fixes it and selects the first item.
   if (menu==-1)
     menu = 0;
   menuwindow &m = *(pp.p[menu]);
   int item = (menu == pp.menu_number) ? pp.item_number : m.selected;
-  while (++item < m.numitems) {
-    const Fl_Menu_Item* m1 = m.menu->next(item);
-    if (m1->activevisible()) {setitem(m1, menu, item); return 1;}
+  while (m.numitems >= 2) {
+    while (++item < m.numitems) {
+      const Fl_Menu_Item* m1 = m.menu->next(item);
+      if (m1->activevisible()) {setitem(m1, menu, item); return 1;}
+    }
+    item = -1;
   }
   return 0;
 }
@@ -713,10 +716,12 @@ static int backward(int menu) { // previous item in menu menu if possible
   menustate &pp = *p;
   menuwindow &m = *(pp.p[menu]);
   int item = (menu == pp.menu_number) ? pp.item_number : m.selected;
-  if (item < 0) item = m.numitems;
-  while (--item >= 0) {
-    const Fl_Menu_Item* m1 = m.menu->next(item);
-    if (m1->activevisible()) {setitem(m1, menu, item); return 1;}
+  while (m.numitems >= 2) {
+    while (--item >= 0) {
+      const Fl_Menu_Item* m1 = m.menu->next(item);
+      if (m1->activevisible()) {setitem(m1, menu, item); return 1;}
+    }
+    item = m.numitems;
   }
   return 0;
 }