Support Ctrl + mouse dragging to add a new selection

Fixes #838

src/input_handler.cc

@@ -75,12 +75,21 @@ struct MouseHandler
 
         Buffer& buffer = context.buffer();
         BufferCoord cursor;
-        switch (key.modifiers)
+        auto& selections = context.selections();
+        switch ((Key::Modifiers)(key.modifiers & Key::Modifiers::MouseEvent))
         {
         case Key::Modifiers::MousePress:
             m_dragging = true;
             m_anchor = context.window().buffer_coord(key.coord());
-            context.selections_write_only() = SelectionList{ buffer, m_anchor };
+            if (not (key.modifiers & Key::Modifiers::Control))
+                context.selections_write_only() = { buffer, m_anchor};
+            else
+            {
+                size_t main = selections.size();
+                selections.push_back({m_anchor});
+                selections.set_main_index(main);
+                selections.sort_and_merge_overlapping();
+            }
             return true;
 
         case Key::Modifiers::MouseRelease:
@@ -88,16 +97,16 @@ struct MouseHandler
                 return true;
             m_dragging = false;
             cursor = context.window().buffer_coord(key.coord());
-            context.selections_write_only() =
+            selections.main() = {buffer.clamp(m_anchor), cursor};
-                SelectionList{ buffer, Selection{buffer.clamp(m_anchor), cursor} };
+            selections.sort_and_merge_overlapping();
             return true;
 
         case Key::Modifiers::MousePos:
             if (not m_dragging)
                 return true;
             cursor = context.window().buffer_coord(key.coord());
-            context.selections_write_only() =
+            selections.main() = {buffer.clamp(m_anchor), cursor};
-                SelectionList{ buffer, Selection{buffer.clamp(m_anchor), cursor} };
+            selections.sort_and_merge_overlapping();
             return true;
 
         case Key::Modifiers::MouseWheelDown:

src/keys.cc

@@ -113,10 +113,10 @@ KeyList parse_keys(StringView str)
 
 String key_to_str(Key key)
 {
-    if (key.modifiers & Key::Modifiers::MouseEvent)
+    if (auto mouse_event = (key.modifiers & Key::Modifiers::MouseEvent))
     {
         const auto coord = key.coord() + DisplayCoord{1,1};
-        switch (key.modifiers)
+        switch ((Key::Modifiers)mouse_event)
         {
             case Key::Modifiers::MousePos:
                 return format("<mouse:move:{}.{}>", coord.line, coord.column);

src/keys.hh

@@ -100,12 +100,6 @@ constexpr Key ctrlalt(Codepoint key) { return { Key::Modifiers::ControlAlt, key
 
 constexpr Codepoint encode_coord(DisplayCoord coord) { return (Codepoint)(((int)coord.line << 16) | ((int)coord.column & 0x0000FFFF)); }
 
-constexpr Key mouse_press(DisplayCoord pos) { return { Key::Modifiers::MousePress, encode_coord(pos) }; }
-constexpr Key mouse_release(DisplayCoord pos) { return { Key::Modifiers::MouseRelease, encode_coord(pos) }; }
-constexpr Key mouse_pos(DisplayCoord pos) { return { Key::Modifiers::MousePos, encode_coord(pos) }; }
-constexpr Key mouse_wheel_down(DisplayCoord pos) { return { Key::Modifiers::MouseWheelDown, encode_coord(pos) }; }
-constexpr Key mouse_wheel_up(DisplayCoord pos) { return { Key::Modifiers::MouseWheelUp, encode_coord(pos) }; }
-
 constexpr Key resize(DisplayCoord dim) { return { Key::Modifiers::Resize, encode_coord(dim) }; }
 
 inline size_t hash_value(const Key& key) { return hash_values(key.modifiers, key.key); }

src/ncurses_ui.cc

@@ -487,6 +487,7 @@ bool NCursesUI::is_key_available()
     return c != ERR;
 }
 
+
 Key NCursesUI::get_key()
 {
     check_resize();
@@ -498,12 +499,27 @@ Key NCursesUI::get_key()
         MEVENT ev;
         if (getmouse(&ev) == OK)
         {
-            DisplayCoord pos{ ev.y - (m_status_on_top ? 1 : 0), ev.x };
+            auto get_modifiers = [this](mmask_t mask) {
-            if (BUTTON_PRESS(ev.bstate, 1)) return mouse_press(pos);
+                Key::Modifiers res{};
-            if (BUTTON_RELEASE(ev.bstate, 1)) return mouse_release(pos);
+
-            if (BUTTON_PRESS(ev.bstate, m_wheel_down_button)) return mouse_wheel_down(pos);
+                if (mask & BUTTON_CTRL)
-            if (BUTTON_PRESS(ev.bstate, m_wheel_up_button)) return mouse_wheel_up(pos);
+                    res |= Key::Modifiers::Control;
-            return mouse_pos(pos);
+                if (mask & BUTTON_ALT)
+                    res |= Key::Modifiers::Alt;
+
+                if (BUTTON_PRESS(mask, 1))
+                    return res | Key::Modifiers::MousePress;
+                if (BUTTON_RELEASE(mask, 1))
+                    return res | Key::Modifiers::MouseRelease;
+                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 { get_modifiers(ev.bstate),
+                     encode_coord({ ev.y - (m_status_on_top ? 1 : 0), ev.x }) };
         }
     }