Make scrolling speed configurable

The UI now can send a 'Scroll' key, whose value is the scrolling
amount encoded as a signed integer. This replaces the MouseWheelUp
and MouseWheelDown keys.

The NCursesUI now has a ncurses_wheel_scroll_amount ui_option that
controls that amount, it can be negative to swap scrolling direction.

Fixes #3045

7 files changed, 70 insertions, 84 deletions

diff --git a/src/input_handler.cc b/src/input_handler.cc
index 6e6b1e20..07211c30 100644
--- a/src/input_handler.cc
+++ b/src/input_handler.cc
@@ -92,8 +92,7 @@ struct MouseHandler
         Buffer& buffer = context.buffer();
         BufferCoord cursor;
         auto& selections = context.selections();
-        const auto key_modifier = (Key::Modifiers)(key.modifiers & Key::Modifiers::MouseEvent);
-        switch (key_modifier)
+        switch (key.modifiers)
         {
         case Key::Modifiers::MousePressRight:
             m_dragging = false;
@@ -137,14 +136,9 @@ struct MouseHandler
             selections.sort_and_merge_overlapping();
             return true;
 
-        case Key::Modifiers::MouseWheelDown:
+        case Key::Modifiers::Scroll:
             m_dragging = false;
-            scroll_window(context, 3);
-            return true;
-
-        case Key::Modifiers::MouseWheelUp:
-            m_dragging = false;
-            scroll_window(context, -3);
+            scroll_window(context, static_cast<int32_t>(key.key));
             return true;
 
         default: return false;
@@ -232,16 +226,6 @@ public:
         kak_assert(m_state != State::PopOnEnabled);
         ScopedSetBool set_in_on_key{m_in_on_key};
 
-        // Hack to parse keys sent by terminals using the 8th bit to mark the
-        // meta key. In normal mode, give priority to a potential alt-key than
-        // the accentuated character.
-        if (not (key.modifiers & Key::Modifiers::MouseEvent) and
-            key.key >= 127 and key.key < 256)
-        {
-            key.modifiers |= Key::Modifiers::Alt;
-            key.key &= 0x7f;
-        }
-
         bool do_restore_hooks = false;
         auto restore_hooks = on_scope_end([&, this]{
             if (m_hooks_disabled and enabled() and do_restore_hooks)
@@ -253,8 +237,6 @@ public:
 
         const bool transient = context().flags() & Context::Flags::Draft;
 
-        auto cp = key.codepoint();
-
         if (m_mouse_handler.handle_key(key, context()))
         {
             context().print_status({});
@@ -264,7 +246,7 @@ public:
             if (not transient)
                 m_idle_timer.set_next_date(Clock::now() + get_idle_timeout(context()));
         }
-        else if (cp and isdigit(*cp))
+        else if (auto cp = key.codepoint(); cp and isdigit(*cp))
         {
             long long new_val = (long long)m_params.count * 10 + *cp - '0';
             if (new_val > std::numeric_limits<int>::max())
@@ -310,6 +292,15 @@ public:
             if (context().has_client())
                 context().client().info_hide();
 
+            // Hack to parse keys sent by terminals using the 8th bit to mark the
+            // meta key. In normal mode, give priority to a potential alt-key than
+            // the accentuated character.
+            if (key.key >= 127 and key.key < 256)
+            {
+                key.modifiers |= Key::Modifiers::Alt;
+                key.key &= 0x7f;
+            }
+
             do_restore_hooks = true;
             if (auto command = get_normal_command(key))
             {
diff --git a/src/json_ui.cc b/src/json_ui.cc
index b8acd6ad..ebb3b7bf 100644
--- a/src/json_ui.cc
+++ b/src/json_ui.cc
@@ -430,13 +430,18 @@ void JsonUI::eval_json(const Value& json)
             m_on_key({Key::Modifiers::MouseReleaseLeft, coord});
         else if (type == "release_right")
             m_on_key({Key::Modifiers::MouseReleaseRight, coord});
-        else if (type == "wheel_up")
-            m_on_key({Key::Modifiers::MouseWheelUp, coord});
-        else if (type == "wheel_down")
-            m_on_key({Key::Modifiers::MouseWheelDown, coord});
         else
             throw invalid_rpc_request(format("invalid mouse event type: {}", type));
     }
+    else if (method == "scroll")
+    {
+        if (params.size() != 1)
+            throw invalid_rpc_request("scroll needs an amount");
+        else if (not params[0].is_a<int>())
+            throw invalid_rpc_request("scroll amount is not an integer");
+        m_on_key({Key::Modifiers::Scroll, (Codepoint)params[0].as<int>()});
+
+    }
     else if (method == "menu_select")
     {
         if (params.size() != 1)
diff --git a/src/keys.cc b/src/keys.cc
index 927baed9..8254f6cb 100644
--- a/src/keys.cc
+++ b/src/keys.cc
@@ -146,32 +146,24 @@ KeyList parse_keys(StringView str)
 
 String key_to_str(Key key)
 {
-    if (auto mouse_event = (key.modifiers & Key::Modifiers::MouseEvent))
+    const auto coord = key.coord() + DisplayCoord{1,1};
+    switch (key.modifiers)
     {
-        const auto coord = key.coord() + DisplayCoord{1,1};
-        switch ((Key::Modifiers)mouse_event)
-        {
-            case Key::Modifiers::MousePos:
-                return format("<mouse:move:{}.{}>", coord.line, coord.column);
-            case Key::Modifiers::MousePressLeft:
-                return format("<mouse:press_left:{}.{}>", coord.line, coord.column);
-            case Key::Modifiers::MousePressRight:
-                return format("<mouse:press_right:{}.{}>", coord.line, coord.column);
-            case Key::Modifiers::MouseReleaseLeft:
-                return format("<mouse:release_left:{}.{}>", coord.line, coord.column);
-            case Key::Modifiers::MouseReleaseRight:
-                return format("<mouse:release_right:{}.{}>", coord.line, coord.column);
-            case Key::Modifiers::MouseWheelDown:
-                return "<mouse:wheel_down>";
-            case Key::Modifiers::MouseWheelUp:
-                return "<mouse:wheel_up>";
-            default: kak_assert(false);
-        }
-    }
-    else if (key.modifiers == Key::Modifiers::Resize)
-    {
-        auto size = key.coord() + DisplayCoord{1,1};
-        return format("<resize:{}.{}>", size.line, size.column);
+        case Key::Modifiers::MousePos:
+            return format("<mouse:move:{}.{}>", coord.line, coord.column);
+        case Key::Modifiers::MousePressLeft:
+            return format("<mouse:press_left:{}.{}>", coord.line, coord.column);
+        case Key::Modifiers::MousePressRight:
+            return format("<mouse:press_right:{}.{}>", coord.line, coord.column);
+        case Key::Modifiers::MouseReleaseLeft:
+            return format("<mouse:release_left:{}.{}>", coord.line, coord.column);
+        case Key::Modifiers::MouseReleaseRight:
+            return format("<mouse:release_right:{}.{}>", coord.line, coord.column);
+        case Key::Modifiers::Scroll:
+            return format("<scroll:{}>", static_cast<int>(key.key));
+        case Key::Modifiers::Resize:
+            return format("<resize:{}.{}>", coord.line, coord.column);
+        default: break;
     }
 
     bool named = false;
diff --git a/src/keys.hh b/src/keys.hh
index 74d1b545..84707faf 100644
--- a/src/keys.hh
+++ b/src/keys.hh
@@ -26,14 +26,9 @@ struct Key
         MouseReleaseLeft  = 1 << 5,
         MouseReleaseRight = 1 << 6,
         MousePos          = 1 << 7,
-        MouseWheelDown    = 1 << 8,
-        MouseWheelUp      = 1 << 9,
-        MouseEvent        = MousePressLeft | MousePressRight |
-                            MouseReleaseLeft | MouseReleaseRight |
-                            MousePos | MouseWheelDown | MouseWheelUp,
-
-        Resize     = 1 << 10,
-        MenuSelect = 1 << 11,
+        Scroll     = 1 << 8,
+        Resize     = 1 << 9,
+        MenuSelect = 1 << 10,
     };
     enum NamedKey : Codepoint
     {
diff --git a/src/main.cc b/src/main.cc
index 620a3da8..b724f122 100644
--- a/src/main.cc
+++ b/src/main.cc
@@ -437,6 +437,7 @@ void register_options()
                        "    ncurses_change_colors         bool\n"
                        "    ncurses_wheel_up_button       int\n"
                        "    ncurses_wheel_down_button     int\n"
+                       "    ncurses_wheel_scroll_amount   int\n"
                        "    ncurses_shift_function_key    int\n"
                        "    ncurses_builtin_key_parser    bool\n",
                        UserInterface::Options{});
diff --git a/src/ncurses_ui.cc b/src/ncurses_ui.cc
index 5b6c4bad..58680546 100644
--- a/src/ncurses_ui.cc
+++ b/src/ncurses_ui.cc
@@ -556,31 +556,28 @@ Optional<Key> NCursesUI::get_next_key()
         MEVENT ev;
         if (getmouse(&ev) == OK)
         {
-            auto get_modifiers = [this](mmask_t mask) {
-                Key::Modifiers res{};
-
-                if (mask & BUTTON_CTRL)
-                    res |= Key::Modifiers::Control;
-                if (mask & BUTTON_ALT)
-                    res |= Key::Modifiers::Alt;
-
-                if (BUTTON_PRESS(mask, 1))
-                    return res | Key::Modifiers::MousePressLeft;
-                if (BUTTON_PRESS(mask, 3))
-                    return res | Key::Modifiers::MousePressRight;
-                if (BUTTON_RELEASE(mask, 1))
-                    return res | Key::Modifiers::MouseReleaseLeft;
-                if (BUTTON_RELEASE(mask, 3))
-                    return res | Key::Modifiers::MouseReleaseRight;
-                if (BUTTON_PRESS(mask, m_wheel_down_button))
-                    return res | Key::Modifiers::MouseWheelDown;
-                if (BUTTON_PRESS(mask, m_wheel_up_button))
-                    return res | Key::Modifiers::MouseWheelUp;
-                return res | Key::Modifiers::MousePos;
-            };
-
-            return Key{ get_modifiers(ev.bstate),
-                        encode_coord({ ev.y - content_line_offset(), ev.x }) };
+            const auto mask = ev.bstate;
+            auto coord = encode_coord({ ev.y - content_line_offset(), ev.x });
+
+            Key::Modifiers mod{};
+            if (mask & BUTTON_CTRL)
+                mod |= Key::Modifiers::Control;
+            if (mask & BUTTON_ALT)
+                mod |= Key::Modifiers::Alt;
+
+            if (BUTTON_PRESS(mask, 1))
+                return Key{mod | Key::Modifiers::MousePressLeft, coord};
+            if (BUTTON_PRESS(mask, 3))
+                return Key{mod | Key::Modifiers::MousePressRight, coord};
+            if (BUTTON_RELEASE(mask, 1))
+                return Key{mod | Key::Modifiers::MouseReleaseLeft, coord};
+            if (BUTTON_RELEASE(mask, 3))
+                return Key{mod | Key::Modifiers::MouseReleaseRight, coord};
+            if (BUTTON_PRESS(mask, m_wheel_down_button))
+                return Key{mod | Key::Modifiers::Scroll, static_cast<Codepoint>(m_wheel_scroll_amount)};
+            if (BUTTON_PRESS(mask, m_wheel_up_button))
+                return Key{mod | Key::Modifiers::Scroll, static_cast<Codepoint>(-m_wheel_scroll_amount)};
+            return Key{mod | Key::Modifiers::MousePos, coord};
         }
     }
 
@@ -1278,6 +1275,10 @@ void NCursesUI::set_ui_options(const Options& options)
         auto wheel_down_it = options.find("ncurses_wheel_down_button"_sv);
         m_wheel_down_button = wheel_down_it != options.end() ?
             str_to_int_ifp(wheel_down_it->value).value_or(5) : 5;
+
+        auto wheel_scroll_amount_it = options.find("ncurses_wheel_scroll_amount"_sv);
+        m_wheel_scroll_amount = wheel_scroll_amount_it != options.end() ?
+            str_to_int_ifp(wheel_scroll_amount_it->value).value_or(3) : 3;
     }
 
     {
diff --git a/src/ncurses_ui.hh b/src/ncurses_ui.hh
index c16b6b99..f858db84 100644
--- a/src/ncurses_ui.hh
+++ b/src/ncurses_ui.hh
@@ -140,6 +140,7 @@ private:
     bool m_mouse_enabled = false;
     int m_wheel_up_button = 4;
     int m_wheel_down_button = 5;
+    int m_wheel_scroll_amount = 3;
 
     static constexpr int default_shift_function_key = 12;
     int m_shift_function_key = default_shift_function_key;