Add blinking cursor support

This adds support for blinking the terminal cursor. This can be
controlled either using the configuration file, or using escape
sequences.

The supported control sequences for changing the blinking state are
`CSI Ps SP q` and private mode 12.

1 files changed, 70 insertions, 1 deletions

diff --git a/alacritty/src/event.rs b/alacritty/src/event.rs
index c1f81300..8ecf6f00 100644
--- a/alacritty/src/event.rs
+++ b/alacritty/src/event.rs
@@ -67,6 +67,7 @@ pub enum Event {
     Scroll(Scroll),
     ConfigReload(PathBuf),
     Message(Message),
+    BlinkCursor,
     SearchNext,
 }
 
@@ -150,6 +151,7 @@ pub struct ActionContext<'a, N, T> {
     pub urls: &'a Urls,
     pub scheduler: &'a mut Scheduler,
     pub search_state: &'a mut SearchState,
+    cursor_hidden: &'a mut bool,
     cli_options: &'a CLIOptions,
     font_size: &'a mut Size,
 }
@@ -495,6 +497,28 @@ impl<'a, N: Notify + 'a, T: EventListener> input::ActionContext<T> for ActionCon
         }
     }
 
+    /// Handle keyboard typing start.
+    ///
+    /// This will temporarily disable some features like terminal cursor blinking or the mouse
+    /// cursor.
+    ///
+    /// All features are re-enabled again automatically.
+    #[inline]
+    fn on_typing_start(&mut self) {
+        // Disable cursor blinking.
+        let blink_interval = self.config.cursor.blink_interval();
+        if let Some(timer) = self.scheduler.get_mut(TimerId::BlinkCursor) {
+            timer.deadline = Instant::now() + Duration::from_millis(blink_interval);
+            *self.cursor_hidden = false;
+            self.terminal.dirty = true;
+        }
+
+        // Hide mouse cursor.
+        if self.config.ui_config.mouse.hide_when_typing {
+            self.window.set_mouse_visible(false);
+        }
+    }
+
     #[inline]
     fn search_direction(&self) -> Direction {
         self.search_state.direction
@@ -667,6 +691,33 @@ impl<'a, N: Notify + 'a, T: EventListener> ActionContext<'a, N, T> {
         origin.line = (origin.line as isize + self.search_state.display_offset_delta) as usize;
         origin
     }
+
+    /// Update the cursor blinking state.
+    fn update_cursor_blinking(&mut self) {
+        // Get config cursor style.
+        let mut cursor_style = self.config.cursor.style;
+        if self.terminal.mode().contains(TermMode::VI) {
+            cursor_style = self.config.cursor.vi_mode_style.unwrap_or(cursor_style);
+        };
+
+        // Check terminal cursor style.
+        let terminal_blinking = self.terminal.cursor_style().blinking;
+        let blinking = cursor_style.blinking_override().unwrap_or(terminal_blinking);
+
+        // Update cursor blinking state.
+        self.scheduler.unschedule(TimerId::BlinkCursor);
+        if blinking && self.terminal.is_focused {
+            self.scheduler.schedule(
+                GlutinEvent::UserEvent(Event::BlinkCursor),
+                Duration::from_millis(self.config.cursor.blink_interval()),
+                true,
+                TimerId::BlinkCursor,
+            )
+        } else {
+            *self.cursor_hidden = false;
+            self.terminal.dirty = true;
+        }
+    }
 }
 
 #[derive(Debug, Eq, PartialEq)]
@@ -804,6 +855,12 @@ impl<N: Notify + OnResize> Processor<N> {
     {
         let mut scheduler = Scheduler::new();
 
+        // Start the initial cursor blinking timer.
+        if self.config.cursor.style().blinking {
+            let event: Event = TerminalEvent::CursorBlinkingChange(true).into();
+            self.event_queue.push(event.into());
+        }
+
         event_loop.run_return(|event, event_loop, control_flow| {
             if self.config.ui_config.debug.print_events {
                 info!("glutin event: {:?}", event);
@@ -873,6 +930,7 @@ impl<N: Notify + OnResize> Processor<N> {
                 scheduler: &mut scheduler,
                 search_state: &mut self.search_state,
                 cli_options: &self.cli_options,
+                cursor_hidden: &mut self.display.cursor_hidden,
                 event_loop,
             };
             let mut processor = input::Processor::new(context, &self.display.highlighted_url);
@@ -953,6 +1011,10 @@ impl<N: Notify + OnResize> Processor<N> {
                 Event::SearchNext => processor.ctx.goto_match(None),
                 Event::ConfigReload(path) => Self::reload_config(&path, processor),
                 Event::Scroll(scroll) => processor.ctx.scroll(scroll),
+                Event::BlinkCursor => {
+                    *processor.ctx.cursor_hidden ^= true;
+                    processor.ctx.terminal.dirty = true;
+                },
                 Event::TerminalEvent(event) => match event {
                     TerminalEvent::Title(title) => {
                         let ui_config = &processor.ctx.config.ui_config;
@@ -983,6 +1045,9 @@ impl<N: Notify + OnResize> Processor<N> {
                     },
                     TerminalEvent::MouseCursorDirty => processor.reset_mouse_cursor(),
                     TerminalEvent::Exit => (),
+                    TerminalEvent::CursorBlinkingChange(_) => {
+                        processor.ctx.update_cursor_blinking();
+                    },
                 },
             },
             GlutinEvent::RedrawRequested(_) => processor.ctx.terminal.dirty = true,
@@ -1033,6 +1098,7 @@ impl<N: Notify + OnResize> Processor<N> {
                                 processor.ctx.window.set_mouse_visible(true);
                             }
 
+                            processor.ctx.update_cursor_blinking();
                             processor.on_focus_change(is_focused);
                         }
                     },
@@ -1111,7 +1177,7 @@ impl<N: Notify + OnResize> Processor<N> {
 
         processor.ctx.terminal.update_config(&config);
 
-        // Reload cursor if we've changed its thickness.
+        // Reload cursor if its thickness has changed.
         if (processor.ctx.config.cursor.thickness() - config.cursor.thickness()).abs()
             > std::f64::EPSILON
         {
@@ -1154,6 +1220,9 @@ impl<N: Notify + OnResize> Processor<N> {
 
         *processor.ctx.config = config;
 
+        // Update cursor blinking.
+        processor.ctx.update_cursor_blinking();
+
         processor.ctx.terminal.dirty = true;
     }