Updated the implementation for hscroll area

lib/interactive_viewer.ml

@@ -122,12 +122,19 @@ let view (patches : Patch.t list) =
     | None -> failwith "zipper_of_list: empty list"
   in
   let curr_scroll_state = Lwd.var W.default_scroll_state in
+  let curr_scroll_state_h = Lwd.var W.default_scroll_state in
   let change_scroll_state _action state =
     let off_screen = state.W.position > state.W.bound in
     if off_screen then
       Lwd.set curr_scroll_state { state with position = state.W.bound }
     else Lwd.set curr_scroll_state state
   in
+  let change_scroll_state_h _action state =
+    let off_screen = state.W.position > state.W.bound in
+    if off_screen then
+      Lwd.set curr_scroll_state_h { state with position = state.W.bound }
+    else Lwd.set curr_scroll_state_h state
+  in
   let ui =
     let$* help_visible = Lwd.get help in
     if help_visible then
@@ -149,9 +156,19 @@ let view (patches : Patch.t list) =
           operation_info z_patches;
           change_summary z_patches;
           current_operation z_patches;
-          W.vscroll_area
-            ~state:(Lwd.get curr_scroll_state)
-            ~change:change_scroll_state
+          (* W.vscroll_area
+               ~state:(Lwd.get curr_scroll_state)
+               ~change:change_scroll_state
+             @@ W.hscroll_area
+                  ~state:(Lwd.get curr_scroll_state_h)
+                  ~change:change_scroll_state_h
+             @@ current_hunks z_patches; *)
+          W.hscroll_area
+            ~state:(Lwd.get curr_scroll_state_h)
+            ~change:change_scroll_state_h
+          @@ W.vscroll_area
+               ~state:(Lwd.get curr_scroll_state)
+               ~change:change_scroll_state
           @@ current_hunks z_patches;
           Lwd.pure
           @@ Ui.keyboard_area

vendor/lwd/lib/nottui/nottui_widgets.ml

@@ -196,6 +196,48 @@ let vscroll_area ~state ~change t =
     |> Ui.mouse_area (scroll_handler state)
     |> Ui.keyboard_area (focus_handler state)
   end
+let hscroll_area ~state ~change t =
+  let visible = ref (-1) in
+  let total = ref (-1) in
+  let scroll state delta =
+      let position = state.position + delta in
+      let position = clampi position ~min:0 ~max:state.bound in
+      if position <> state.position then 
+        change `Action {state with position};
+      `Handled
+  in
+  let focus_handler state = function
+  | `Arrow `Left , [] -> scroll state (-scroll_step) 
+  | `Arrow `Right, [] -> scroll state (+scroll_step) 
+  | _ -> `Unhandled
+  in
+  (* let scroll_handler state ~x:_ ~y:_ = function
+    | `Scroll `Up   -> scroll state (0)
+    | `Scroll `Down -> scroll state (0)
+    | _ -> `Unhandled
+  in *)
+  Lwd.map2 t state ~f:begin fun t state ->
+    t
+    |> Ui.shift_area state.position 0
+    |> Ui.resize ~w:0 ~sw:1
+    |> Ui.size_sensor (fun ~w ~h:_ ->
+        let tchange =
+          if !total <> (Ui.layout_spec t).Ui.w 
+            then (total := (Ui.layout_spec t).Ui.w; true)
+          else false
+        in
+        let vchange =
+          if !visible <> w 
+            then (visible := w; true)
+          else false
+        in
+        if tchange || vchange then
+          change `Content {state with visible = !visible; total = !total;
+                                      bound = maxi 0 (!total - !visible); }
+      )
+    (* |> Ui.mouse_area (scroll_handler state) *)
+    |> Ui.keyboard_area (focus_handler state)
+  end
 
 let scroll_area ?(offset=0,0) t =
   let offset = Lwd.var offset in

vendor/lwd/lib/nottui/nottui_widgets.mli

@@ -37,6 +37,10 @@ val vscroll_area :
   state:scroll_state Lwd.t ->
   change:([> `Action | `Content ] -> scroll_state -> unit) ->
   ui Lwd.t -> ui Lwd.t
+val hscroll_area :
+  state:scroll_state Lwd.t ->
+  change:([> `Action | `Content ] -> scroll_state -> unit) ->
+  ui Lwd.t -> ui Lwd.t
 
 val scroll_area :
   ?offset:int * int -> ui Lwd.t -> ui Lwd.t