add scroll coordinates

adds scroll amount in the upper 16-bits of `Key.modifiers`, reclaiming
the space in `Key.key` for coordinates. Previously, while mouse events
included their coordinates, scrolling did not. Scroll events are now
emitted as <scroll:amount:line.column>.

3 files changed, 7 insertions, 6 deletions

diff --git a/src/keys.cc b/src/keys.cc
index 5ba44181..ad66658a 100644
--- a/src/keys.cc
+++ b/src/keys.cc
@@ -7,6 +7,7 @@
 #include "utf8_iterator.hh"
 #include "utils.hh"
 #include "string_utils.hh"
+#include "terminal_ui.hh"
 
 namespace Kakoune
 {
@@ -196,7 +197,7 @@ String to_string(Key key)
     else if (key.modifiers & Key::Modifiers::MouseRelease)
         res = format("mouse:release:{}:{}.{}", key.mouse_button(), coord.line, coord.column);
     else if (key.modifiers & Key::Modifiers::Scroll)
-        res = format("scroll:{}", static_cast<int>(key.key));
+        res = format("scroll:{}:{}.{}", key.scroll_amount(), coord.line, coord.column);
     else if (key.modifiers & Key::Modifiers::Resize)
         res = format("resize:{}.{}", coord.line, coord.column);
     else
diff --git a/src/keys.hh b/src/keys.hh
index ccafe336..b4796ea5 100644
--- a/src/keys.hh
+++ b/src/keys.hh
@@ -91,6 +91,7 @@ struct Key
 
     constexpr DisplayCoord coord() const { return {(int)((key & 0xFFFF0000) >> 16), (int)(key & 0x0000FFFF)}; }
     constexpr MouseButton mouse_button() { return MouseButton{((int)modifiers & (int)Modifiers::MouseButtonMask) >> 6}; }
+    constexpr int scroll_amount() { return (int)modifiers >> 16; }
     static Modifiers to_modifier(MouseButton button) { return Key::Modifiers{((int)button << 6) & (int)Modifiers::MouseButtonMask}; }
 
     Optional<Codepoint> codepoint() const;
diff --git a/src/terminal_ui.cc b/src/terminal_ui.cc
index 33574e90..01afab48 100644
--- a/src/terminal_ui.cc
+++ b/src/terminal_ui.cc
@@ -798,9 +798,8 @@ Optional<Key> TerminalUI::get_next_key()
             return Key{mod | Key::to_modifier(button), coord};
         };
 
-        auto mouse_scroll = [this](Key::Modifiers mod, bool down) -> Key {
-            return {mod | Key::Modifiers::Scroll,
-                    (Codepoint)((down ? 1 : -1) * m_wheel_scroll_amount)};
+        auto mouse_scroll = [this](Key::Modifiers mod, Codepoint coord, bool down) -> Key {
+            return {mod | Key::Modifiers::Scroll | (Key::Modifiers)((down ? m_wheel_scroll_amount : -1 * m_wheel_scroll_amount) << 16), coord};
         };
 
         auto masked_key = [&](Codepoint key, Codepoint shifted_key = 0) {
@@ -921,8 +920,8 @@ Optional<Key> TerminalUI::get_next_key()
                 else if (int guess = ffs(m_mouse_state) - 1; 0 <= guess and guess < 3)
                     return mouse_button(mod, Key::MouseButton{guess}, coord, true);
                 break;
-            case 64: return mouse_scroll(mod, false);
-            case 65: return mouse_scroll(mod, true);
+            case 64: return mouse_scroll(mod, coord, false);
+            case 65: return mouse_scroll(mod, coord, true);
             }
             return Key{Key::Modifiers::MousePos, coord};
         }