[settings] use a spin button for really large values

starting to solve #795

sw/ground_segment/cockpit/page_settings.ml

@@ -134,14 +134,24 @@ let one_setting = fun (i:int) (do_change:int -> float -> unit) packing dl_settin
             b) in
         (callback, fun j -> try buttons.(truncate j - ilower)#set_active true with _ -> ())
     else (* slider *)
+      let range = upper -. lower in
       let value = (lower +. upper) /. 2. in
-      let adj = GData.adjustment ~value ~lower ~upper:(upper+.step_incr) ~step_incr ~page_incr ~page_size () in
-      let _scale = GRange.scale `HORIZONTAL ~digits ~update_policy:`DELAYED ~adjustment:adj ~packing:hbox#add () in
-      let f = fun _ -> do_change i ((adj#value-.alt_b)/.alt_a)  in
-      let callback = fun () -> modified := true; if auto_but#active then f () in
-      ignore (adj#connect#value_changed ~callback);
-      ignore (auto_but#connect#toggled ~callback);
-      (f, fun x -> try adj#set_value x with _ -> ())
+      if range > 10000. then
+        let adj = GData.adjustment ~value ~lower ~upper:(upper+.step_incr) ~step_incr ~page_incr ~page_size:0. () in
+        let _spinbutton = GEdit.spin_button ~adjustment:adj ~numeric:true ~packing:hbox#add () in
+        let f = fun _ -> do_change i ((adj#value-.alt_b)/.alt_a)  in
+        let callback = fun () -> modified := true; if auto_but#active then f () in
+        ignore (adj#connect#value_changed ~callback);
+        ignore (auto_but#connect#toggled ~callback);
+        (f, fun x -> try adj#set_value x with _ -> ())
+      else
+        let adj = GData.adjustment ~value ~lower ~upper:(upper+.step_incr) ~step_incr ~page_incr ~page_size () in
+        let _scale = GRange.scale `HORIZONTAL ~digits ~update_policy:`DELAYED ~adjustment:adj ~packing:hbox#add () in
+        let f = fun _ -> do_change i ((adj#value-.alt_b)/.alt_a)  in
+        let callback = fun () -> modified := true; if auto_but#active then f () in
+        ignore (adj#connect#value_changed ~callback);
+        ignore (auto_but#connect#toggled ~callback);
+        (f, fun x -> try adj#set_value x with _ -> ())
   in
   let set_default = fun x ->
     if not !modified then set_default x else () in