Add vi action to center view around vi cursor

CHANGELOG.md

@@ -19,6 +19,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 - Support for OpenGL ES 2.0
 - Escape sequence to set underline color (`CSI 58 : 2 : Ps : Ps : Ps m`/`CSI 58 : 5 : Ps m`)
 - Escape sequence to reset underline color (`CSI 59 m`)
+- Vi mode keybinding (z) to center view around vi mode cursor 
 
 ### Changed
 

alacritty.yml

@@ -625,6 +625,8 @@
 #   - ToggleBlockSelection
 #   - ToggleSemanticSelection
 #       Toggle semantic selection based on `selection.semantic_escape_chars`.
+#   - CenterAroundViCursor
+#       Center view around vi mode cursor
 #
 # - Vi mode exclusive cursor motion actions:
 #
@@ -778,6 +780,7 @@
   #- { key: V,      mods: Control,       mode: Vi|~Search, action: ToggleBlockSelection    }
   #- { key: V,      mods: Alt,           mode: Vi|~Search, action: ToggleSemanticSelection }
   #- { key: Return,                      mode: Vi|~Search, action: Open                    }
+  #- { key: Z,                           mode: Vi|~Search, action: CenterAroundViCursor    }
   #- { key: K,                           mode: Vi|~Search, action: Up                      }
   #- { key: J,                           mode: Vi|~Search, action: Down                    }
   #- { key: H,                           mode: Vi|~Search, action: Left                    }

alacritty/src/config/bindings.rs

@@ -275,6 +275,8 @@ pub enum ViAction {
     SearchEnd,
     /// Launch the URL below the vi mode cursor.
     Open,
+    /// Centers the screen around the vi mode cursor.
+    CenterAroundViCursor,
 }
 
 /// Search mode specific actions.
@@ -498,6 +500,8 @@ pub fn default_key_bindings() -> Vec<KeyBinding> {
             ViAction::SearchPrevious;
         Return,                        +BindingMode::VI, ~BindingMode::SEARCH;
             ViAction::Open;
+        Z,                             +BindingMode::VI, ~BindingMode::SEARCH;
+            ViAction::CenterAroundViCursor;
         K,                             +BindingMode::VI, ~BindingMode::SEARCH;
             ViMotion::Up;
         J,                             +BindingMode::VI, ~BindingMode::SEARCH;

alacritty/src/input.rs

@@ -230,6 +230,15 @@ impl<T: EventListener> Execute<T> for Action {
                     ctx.mark_dirty();
                 }
             },
+            Action::Vi(ViAction::CenterAroundViCursor) => {
+                let term = ctx.terminal();
+                let display_offset = term.grid().display_offset() as i32;
+                let target = -display_offset + term.screen_lines() as i32 / 2 - 1;
+                let line = term.vi_mode_cursor.point.line;
+                let scroll_lines = target - line.0;
+
+                ctx.scroll(Scroll::Delta(scroll_lines));
+            },
             Action::Search(SearchAction::SearchFocusNext) => {
                 ctx.advance_search_origin(ctx.search_direction());
             },