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.

13 files changed, 316 insertions, 71 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index a870d9c3..7e9e48ec 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -20,6 +20,12 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 - Wide characters sometimes being cut off
 - Preserve vi mode across terminal `reset`
 
+### Added
+
+- New `cursor.style.blinking` option to set the default blinking state
+- New `cursor.blink_interval` option to configure the blinking frequency
+- Support for cursor blinking escapes (`CSI ? 12 h`, `CSI ? 12 l` and `CSI Ps SP q`)
+
 ## 0.6.0
 
 ### Packaging
diff --git a/alacritty.yml b/alacritty.yml
index 3c6d18ec..2f2e5dc9 100644
--- a/alacritty.yml
+++ b/alacritty.yml
@@ -341,12 +341,23 @@
 
 #cursor:
   # Cursor style
-  #
-  # Values for `style`:
-  #   - ▇ Block
-  #   - _ Underline
-  #   - | Beam
-  #style: Block
+  #style:
+    # Cursor shape
+    #
+    # Values for `shape`:
+    #   - ▇ Block
+    #   - _ Underline
+    #   - | Beam
+    #shape: Block
+
+    # Cursor blinking state
+    #
+    # Values for `blinking`:
+    #   - Never: Prevent the cursor from ever blinking
+    #   - Off: Disable blinking by default
+    #   - On: Enable blinking by default
+    #   - Always: Force the cursor to always blink
+    #blinking: Off
 
   # Vi mode cursor style
   #
@@ -356,6 +367,9 @@
   # See `cursor.style` for available options.
   #vi_mode_style: None
 
+  # Cursor blinking interval in milliseconds.
+  #blink_interval: 750
+
   # If this is `true`, the cursor will be rendered as a hollow box when the
   # window is not focused.
   #unfocused_hollow: true
diff --git a/alacritty/src/cursor.rs b/alacritty/src/cursor.rs
index 8c782185..edf76bf3 100644
--- a/alacritty/src/cursor.rs
+++ b/alacritty/src/cursor.rs
@@ -2,10 +2,10 @@
 
 use crossfont::{BitmapBuffer, Metrics, RasterizedGlyph};
 
-use alacritty_terminal::ansi::CursorStyle;
+use alacritty_terminal::ansi::CursorShape;
 
 pub fn get_cursor_glyph(
-    cursor: CursorStyle,
+    cursor: CursorShape,
     metrics: Metrics,
     offset_x: i8,
     offset_y: i8,
@@ -26,11 +26,11 @@ pub fn get_cursor_glyph(
     }
 
     match cursor {
-        CursorStyle::HollowBlock => get_box_cursor_glyph(height, width, line_width),
-        CursorStyle::Underline => get_underline_cursor_glyph(width, line_width),
-        CursorStyle::Beam => get_beam_cursor_glyph(height, line_width),
-        CursorStyle::Block => get_block_cursor_glyph(height, width),
-        CursorStyle::Hidden => RasterizedGlyph::default(),
+        CursorShape::HollowBlock => get_box_cursor_glyph(height, width, line_width),
+        CursorShape::Underline => get_underline_cursor_glyph(width, line_width),
+        CursorShape::Beam => get_beam_cursor_glyph(height, line_width),
+        CursorShape::Block => get_block_cursor_glyph(height, width),
+        CursorShape::Hidden => RasterizedGlyph::default(),
     }
 }
 
diff --git a/alacritty/src/display.rs b/alacritty/src/display.rs
index af21001e..451874c8 100644
--- a/alacritty/src/display.rs
+++ b/alacritty/src/display.rs
@@ -160,6 +160,9 @@ pub struct Display {
     #[cfg(not(any(target_os = "macos", windows)))]
     pub is_x11: bool,
 
+    /// UI cursor visibility for blinking.
+    pub cursor_hidden: bool,
+
     renderer: QuadRenderer,
     glyph_cache: GlyphCache,
     meter: Meter,
@@ -300,6 +303,7 @@ impl Display {
             is_x11,
             #[cfg(all(feature = "wayland", not(any(target_os = "macos", windows))))]
             wayland_event_queue,
+            cursor_hidden: false,
         })
     }
 
@@ -442,8 +446,9 @@ impl Display {
         let viewport_match = search_state
             .focused_match()
             .and_then(|focused_match| terminal.grid().clamp_buffer_range_to_visible(focused_match));
+        let cursor_hidden = self.cursor_hidden || search_state.regex().is_some();
 
-        let grid_cells = terminal.renderable_cells(config, !search_active).collect::<Vec<_>>();
+        let grid_cells = terminal.renderable_cells(config, !cursor_hidden).collect::<Vec<_>>();
         let visual_bell_intensity = terminal.visual_bell.intensity();
         let background_color = terminal.background_color();
         let cursor_point = terminal.grid().cursor.point;
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;
     }
 
diff --git a/alacritty/src/input.rs b/alacritty/src/input.rs
index 348db610..ce89625b 100644
--- a/alacritty/src/input.rs
+++ b/alacritty/src/input.rs
@@ -103,6 +103,7 @@ pub trait ActionContext<T: EventListener> {
     fn advance_search_origin(&mut self, direction: Direction);
     fn search_direction(&self) -> Direction;
     fn search_active(&self) -> bool;
+    fn on_typing_start(&mut self);
 }
 
 trait Execute<T: EventListener> {
@@ -138,9 +139,7 @@ impl<T: EventListener> Execute<T> for Action {
     fn execute<A: ActionContext<T>>(&self, ctx: &mut A) {
         match *self {
             Action::Esc(ref s) => {
-                if ctx.config().ui_config.mouse.hide_when_typing {
-                    ctx.window_mut().set_mouse_visible(false);
-                }
+                ctx.on_typing_start();
 
                 ctx.clear_selection();
                 ctx.scroll(Scroll::Bottom);
@@ -167,10 +166,7 @@ impl<T: EventListener> Execute<T> for Action {
             Action::ClearSelection => ctx.clear_selection(),
             Action::ToggleViMode => ctx.terminal_mut().toggle_vi_mode(),
             Action::ViMotion(motion) => {
-                if ctx.config().ui_config.mouse.hide_when_typing {
-                    ctx.window_mut().set_mouse_visible(false);
-                }
-
+                ctx.on_typing_start();
                 ctx.terminal_mut().vi_motion(motion)
             },
             Action::ViAction(ViAction::ToggleNormalSelection) => {
@@ -870,6 +866,13 @@ impl<'a, T: EventListener, A: ActionContext<T>> Processor<'a, T, A> {
         self.ctx.window_mut().set_mouse_cursor(mouse_state.into());
     }
 
+    /// Reset mouse cursor based on modifier and terminal state.
+    #[inline]
+    pub fn reset_mouse_cursor(&mut self) {
+        let mouse_state = self.mouse_state();
+        self.ctx.window_mut().set_mouse_cursor(mouse_state.into());
+    }
+
     /// Process a received character.
     pub fn received_char(&mut self, c: char) {
         let suppress_chars = *self.ctx.suppress_chars();
@@ -890,9 +893,7 @@ impl<'a, T: EventListener, A: ActionContext<T>> Processor<'a, T, A> {
             return;
         }
 
-        if self.ctx.config().ui_config.mouse.hide_when_typing {
-            self.ctx.window_mut().set_mouse_visible(false);
-        }
+        self.ctx.on_typing_start();
 
         self.ctx.scroll(Scroll::Bottom);
         self.ctx.clear_selection();
@@ -917,13 +918,6 @@ impl<'a, T: EventListener, A: ActionContext<T>> Processor<'a, T, A> {
         *self.ctx.received_count() += 1;
     }
 
-    /// Reset mouse cursor based on modifier and terminal state.
-    #[inline]
-    pub fn reset_mouse_cursor(&mut self) {
-        let mouse_state = self.mouse_state();
-        self.ctx.window_mut().set_mouse_cursor(mouse_state.into());
-    }
-
     /// Attempt to find a binding and execute its action.
     ///
     /// The provided mode, mods, and key must match what is allowed by a binding
@@ -1270,6 +1264,10 @@ mod tests {
         fn scheduler_mut(&mut self) -> &mut Scheduler {
             unimplemented!();
         }
+
+        fn on_typing_start(&mut self) {
+            unimplemented!();
+        }
     }
 
     macro_rules! test_clickstate {
diff --git a/alacritty/src/renderer/mod.rs b/alacritty/src/renderer/mod.rs
index f63f92fd..af1f3c3e 100644
--- a/alacritty/src/renderer/mod.rs
+++ b/alacritty/src/renderer/mod.rs
@@ -1010,7 +1010,7 @@ impl<'a> RenderApi<'a> {
                 let metrics = glyph_cache.metrics;
                 let glyph = glyph_cache.cursor_cache.entry(cursor_key).or_insert_with(|| {
                     self.load_glyph(&cursor::get_cursor_glyph(
-                        cursor_key.style,
+                        cursor_key.shape,
                         metrics,
                         self.config.font.offset.x,
                         self.config.font.offset.y,
diff --git a/alacritty/src/scheduler.rs b/alacritty/src/scheduler.rs
index db6180ca..5e454141 100644
--- a/alacritty/src/scheduler.rs
+++ b/alacritty/src/scheduler.rs
@@ -14,6 +14,7 @@ type Event = GlutinEvent<'static, AlacrittyEvent>;
 pub enum TimerId {
     SelectionScrolling,
     DelayedSearch,
+    BlinkCursor,
 }
 
 /// Event scheduled to be emitted at a specific time.
diff --git a/alacritty_terminal/src/ansi.rs b/alacritty_terminal/src/ansi.rs
index 877fd65f..7567eba2 100644
--- a/alacritty_terminal/src/ansi.rs
+++ b/alacritty_terminal/src/ansi.rs
@@ -141,6 +141,9 @@ pub trait Handler {
     /// Set the cursor style.
     fn set_cursor_style(&mut self, _: Option<CursorStyle>) {}
 
+    /// Set the cursor shape.
+    fn set_cursor_shape(&mut self, _shape: CursorShape) {}
+
     /// A character to be displayed.
     fn input(&mut self, _c: char) {}
 
@@ -324,9 +327,16 @@ pub trait Handler {
     fn text_area_size_chars<W: io::Write>(&mut self, _: &mut W) {}
 }
 
-/// Describes shape of cursor.
-#[derive(Debug, Eq, PartialEq, Copy, Clone, Hash, Deserialize)]
-pub enum CursorStyle {
+/// Terminal cursor configuration.
+#[derive(Deserialize, Default, Debug, Eq, PartialEq, Copy, Clone, Hash)]
+pub struct CursorStyle {
+    pub shape: CursorShape,
+    pub blinking: bool,
+}
+
+/// Terminal cursor shape.
+#[derive(Deserialize, Debug, Eq, PartialEq, Copy, Clone, Hash)]
+pub enum CursorShape {
     /// Cursor is a block like `▒`.
     Block,
 
@@ -345,9 +355,9 @@ pub enum CursorStyle {
     Hidden,
 }
 
-impl Default for CursorStyle {
-    fn default() -> CursorStyle {
-        CursorStyle::Block
+impl Default for CursorShape {
+    fn default() -> CursorShape {
+        CursorShape::Block
     }
 }
 
@@ -874,13 +884,13 @@ where
                     && params[1].len() >= 13
                     && params[1][0..12] == *b"CursorShape="
                 {
-                    let style = match params[1][12] as char {
-                        '0' => CursorStyle::Block,
-                        '1' => CursorStyle::Beam,
-                        '2' => CursorStyle::Underline,
+                    let shape = match params[1][12] as char {
+                        '0' => CursorShape::Block,
+                        '1' => CursorShape::Beam,
+                        '2' => CursorShape::Underline,
                         _ => return unhandled(params),
                     };
-                    self.handler.set_cursor_style(Some(style));
+                    self.handler.set_cursor_shape(shape);
                     return;
                 }
                 unhandled(params);
@@ -1065,18 +1075,21 @@ where
             ('P', None) => handler.delete_chars(Column(next_param_or(1) as usize)),
             ('q', Some(b' ')) => {
                 // DECSCUSR (CSI Ps SP q) -- Set Cursor Style.
-                let style = match next_param_or(0) {
+                let cursor_style_id = next_param_or(0);
+                let shape = match cursor_style_id {
                     0 => None,
-                    1 | 2 => Some(CursorStyle::Block),
-                    3 | 4 => Some(CursorStyle::Underline),
-                    5 | 6 => Some(CursorStyle::Beam),
+                    1 | 2 => Some(CursorShape::Block),
+                    3 | 4 => Some(CursorShape::Underline),
+                    5 | 6 => Some(CursorShape::Beam),
                     _ => {
                         unhandled!();
                         return;
                     },
                 };
+                let cursor_style =
+                    shape.map(|shape| CursorStyle { shape, blinking: cursor_style_id % 2 == 1 });
 
-                handler.set_cursor_style(style);
+                handler.set_cursor_style(cursor_style);
             },
             ('r', None) => {
                 let top = next_param_or(1) as usize;
diff --git a/alacritty_terminal/src/config/mod.rs b/alacritty_terminal/src/config/mod.rs
index 98849d90..f3221920 100644
--- a/alacritty_terminal/src/config/mod.rs
+++ b/alacritty_terminal/src/config/mod.rs
@@ -1,3 +1,4 @@
+use std::cmp::max;
 use std::collections::HashMap;
 use std::fmt::Display;
 use std::path::PathBuf;
@@ -10,15 +11,16 @@ mod bell;
 mod colors;
 mod scrolling;
 
-use crate::ansi::CursorStyle;
+use crate::ansi::{CursorShape, CursorStyle};
 
 pub use crate::config::bell::{BellAnimation, BellConfig};
 pub use crate::config::colors::Colors;
 pub use crate::config::scrolling::Scrolling;
 
 pub const LOG_TARGET_CONFIG: &str = "alacritty_config";
-const MAX_SCROLLBACK_LINES: u32 = 100_000;
 const DEFAULT_CURSOR_THICKNESS: f32 = 0.15;
+const MAX_SCROLLBACK_LINES: u32 = 100_000;
+const MIN_BLINK_INTERVAL: u64 = 10;
 
 pub type MockConfig = Config<HashMap<String, serde_yaml::Value>>;
 
@@ -121,9 +123,11 @@ impl Default for EscapeChars {
 #[derive(Deserialize, Copy, Clone, Debug, PartialEq)]
 pub struct Cursor {
     #[serde(deserialize_with = "failure_default")]
-    pub style: CursorStyle,
+    pub style: ConfigCursorStyle,
     #[serde(deserialize_with = "option_explicit_none")]
-    pub vi_mode_style: Option<CursorStyle>,
+    pub vi_mode_style: Option<ConfigCursorStyle>,
+    #[serde(deserialize_with = "failure_default")]
+    blink_interval: BlinkInterval,
     #[serde(deserialize_with = "deserialize_cursor_thickness")]
     thickness: Percentage,
     #[serde(deserialize_with = "failure_default")]
@@ -140,6 +144,21 @@ impl Cursor {
     pub fn thickness(self) -> f64 {
         self.thickness.0 as f64
     }
+
+    #[inline]
+    pub fn style(self) -> CursorStyle {
+        self.style.into()
+    }
+
+    #[inline]
+    pub fn vi_mode_style(self) -> Option<CursorStyle> {
+        self.vi_mode_style.map(From::from)
+    }
+
+    #[inline]
+    pub fn blink_interval(self) -> u64 {
+        max(self.blink_interval.0, MIN_BLINK_INTERVAL)
+    }
 }
 
 impl Default for Cursor {
@@ -149,10 +168,20 @@ impl Default for Cursor {
             vi_mode_style: Default::default(),
             thickness: Percentage::new(DEFAULT_CURSOR_THICKNESS),
             unfocused_hollow: Default::default(),
+            blink_interval: Default::default(),
         }
     }
 }
 
+#[derive(Deserialize, Copy, Clone, Debug, PartialEq)]
+struct BlinkInterval(u64);
+
+impl Default for BlinkInterval {
+    fn default() -> Self {
+        BlinkInterval(750)
+    }
+}
+
 fn deserialize_cursor_thickness<'a, D>(deserializer: D) -> Result<Percentage, D::Error>
 where
     D: Deserializer<'a>,
@@ -174,6 +203,75 @@ where
 }
 
 #[serde(untagged)]
+#[derive(Deserialize, Debug, Copy, Clone, PartialEq, Eq)]
+pub enum ConfigCursorStyle {
+    Shape(CursorShape),
+    WithBlinking {
+        #[serde(default, deserialize_with = "failure_default")]
+        shape: CursorShape,
+        #[serde(default, deserialize_with = "failure_default")]
+        blinking: CursorBlinking,
+    },
+}
+
+impl Default for ConfigCursorStyle {
+    fn default() -> Self {
+        Self::WithBlinking { shape: CursorShape::default(), blinking: CursorBlinking::default() }
+    }
+}
+
+impl ConfigCursorStyle {
+    /// Check if blinking is force enabled/disabled.
+    pub fn blinking_override(&self) -> Option<bool> {
+        match self {
+            Self::Shape(_) => None,
+            Self::WithBlinking { blinking, .. } => blinking.blinking_override(),
+        }
+    }
+}
+
+impl From<ConfigCursorStyle> for CursorStyle {
+    fn from(config_style: ConfigCursorStyle) -> Self {
+        match config_style {
+            ConfigCursorStyle::Shape(shape) => Self { shape, blinking: false },
+            ConfigCursorStyle::WithBlinking { shape, blinking } => {
+                Self { shape, blinking: blinking.into() }
+            },
+        }
+    }
+}
+
+#[derive(Deserialize, Debug, Copy, Clone, PartialEq, Eq)]
+pub enum CursorBlinking {
+    Never,
+    Off,
+    On,
+    Always,
+}
+
+impl Default for CursorBlinking {
+    fn default() -> Self {
+        CursorBlinking::Off
+    }
+}
+
+impl CursorBlinking {
+    fn blinking_override(&self) -> Option<bool> {
+        match self {
+            Self::Never => Some(false),
+            Self::Off | Self::On => None,
+            Self::Always => Some(true),
+        }
+    }
+}
+
+impl Into<bool> for CursorBlinking {
+    fn into(self) -> bool {
+        self == Self::On || self == Self::Always
+    }
+}
+
+#[serde(untagged)]
 #[derive(Deserialize, Debug, Clone, PartialEq, Eq)]
 pub enum Program {
     Just(String),
diff --git a/alacritty_terminal/src/event.rs b/alacritty_terminal/src/event.rs
index c7129b24..351b7bc2 100644
--- a/alacritty_terminal/src/event.rs
+++ b/alacritty_terminal/src/event.rs
@@ -11,6 +11,7 @@ pub enum Event {
     ResetTitle,
     ClipboardStore(ClipboardType, String),
     ClipboardLoad(ClipboardType, Arc<dyn Fn(&str) -> String + Sync + Send + 'static>),
+    CursorBlinkingChange(bool),
     Wakeup,
     Bell,
     Exit,
@@ -27,6 +28,7 @@ impl Debug for Event {
             Event::Wakeup => write!(f, "Wakeup"),
             Event::Bell => write!(f, "Bell"),
             Event::Exit => write!(f, "Exit"),
+            Event::CursorBlinkingChange(blinking) => write!(f, "CursorBlinking({})", blinking),
         }
     }
 }
diff --git a/alacritty_terminal/src/term/mod.rs b/alacritty_terminal/src/term/mod.rs
index 926b89d7..accb4dc1 100644
--- a/alacritty_terminal/src/term/mod.rs
+++ b/alacritty_terminal/src/term/mod.rs
@@ -12,7 +12,7 @@ use serde::{Deserialize, Serialize};
 use unicode_width::UnicodeWidthChar;
 
 use crate::ansi::{
-    self, Attr, CharsetIndex, Color, CursorStyle, Handler, NamedColor, StandardCharset,
+    self, Attr, CharsetIndex, Color, CursorShape, CursorStyle, Handler, NamedColor, StandardCharset,
 };
 use crate::config::{BellAnimation, BellConfig, Config};
 use crate::event::{Event, EventListener};
@@ -61,7 +61,7 @@ struct RenderableCursor {
 /// A key for caching cursor glyphs.
 #[derive(Debug, Eq, PartialEq, Copy, Clone, Hash, Deserialize)]
 pub struct CursorKey {
-    pub style: CursorStyle,
+    pub shape: CursorShape,
     pub is_wide: bool,
 }
 
@@ -202,7 +202,7 @@ impl<'a, C> RenderableCellsIter<'a, C> {
         let cell = self.inner.next()?;
         let mut cell = RenderableCell::new(self, cell);
 
-        if self.cursor.key.style == CursorStyle::Block {
+        if self.cursor.key.shape == CursorShape::Block {
             cell.fg = match self.cursor.cursor_color {
                 // Apply cursor color, or invert the cursor if it has a fixed background
                 // close to the cell's background.
@@ -249,7 +249,7 @@ impl<'a, C> RenderableCellsIter<'a, C> {
         };
 
         // Do not invert block cursor at selection boundaries.
-        if self.cursor.key.style == CursorStyle::Block
+        if self.cursor.key.shape == CursorShape::Block
             && self.cursor.point == point
             && (selection.start == point
                 || selection.end == point
@@ -855,8 +855,8 @@ impl<T> Term<T> {
             original_colors: colors,
             semantic_escape_chars: config.selection.semantic_escape_chars().to_owned(),
             cursor_style: None,
-            default_cursor_style: config.cursor.style,
-            vi_mode_cursor_style: config.cursor.vi_mode_style,
+            default_cursor_style: config.cursor.style(),
+            vi_mode_cursor_style: config.cursor.vi_mode_style(),
             event_proxy,
             is_focused: true,
             title: None,
@@ -885,8 +885,8 @@ impl<T> Term<T> {
         if let Some(0) = config.scrolling.faux_multiplier() {
             self.mode.remove(TermMode::ALTERNATE_SCROLL);
         }
-        self.default_cursor_style = config.cursor.style;
-        self.vi_mode_cursor_style = config.cursor.vi_mode_style;
+        self.default_cursor_style = config.cursor.style();
+        self.vi_mode_cursor_style = config.cursor.vi_mode_style();
 
         let title_event = match &self.title {
             Some(title) => Event::Title(title.clone()),
@@ -1207,7 +1207,10 @@ impl<T> Term<T> {
 
     /// Toggle the vi mode.
     #[inline]
-    pub fn toggle_vi_mode(&mut self) {
+    pub fn toggle_vi_mode(&mut self)
+    where
+        T: EventListener,
+    {
         self.mode ^= TermMode::VI;
 
         let vi_mode = self.mode.contains(TermMode::VI);
@@ -1226,6 +1229,9 @@ impl<T> Term<T> {
             self.cancel_search();
         }
 
+        // Update UI about cursor blinking state changes.
+        self.event_proxy.send_event(Event::CursorBlinkingChange(self.cursor_style().blinking));
+
         self.dirty = true;
     }
 
@@ -1332,6 +1338,20 @@ impl<T> Term<T> {
         &self.semantic_escape_chars
     }
 
+    /// Active terminal cursor style.
+    ///
+    /// While vi mode is active, this will automatically return the vi mode cursor style.
+    #[inline]
+    pub fn cursor_style(&self) -> CursorStyle {
+        let cursor_style = self.cursor_style.unwrap_or(self.default_cursor_style);
+
+        if self.mode.contains(TermMode::VI) {
+            self.vi_mode_cursor_style.unwrap_or(cursor_style)
+        } else {
+            cursor_style
+        }
+    }
+
     /// Insert a linebreak at the current cursor position.
     #[inline]
     fn wrapline(&mut self)
@@ -1395,18 +1415,18 @@ impl<T> Term<T> {
         // Cursor shape.
         let hidden =
             !self.mode.contains(TermMode::SHOW_CURSOR) || point.line >= self.screen_lines();
-        let cursor_style = if hidden && !vi_mode {
+        let cursor_shape = if hidden && !vi_mode {
             point.line = Line(0);
-            CursorStyle::Hidden
+            CursorShape::Hidden
         } else if !self.is_focused && config.cursor.unfocused_hollow() {
-            CursorStyle::HollowBlock
+            CursorShape::HollowBlock
         } else {
             let cursor_style = self.cursor_style.unwrap_or(self.default_cursor_style);
 
             if vi_mode {
-                self.vi_mode_cursor_style.unwrap_or(cursor_style)
+                self.vi_mode_cursor_style.unwrap_or(cursor_style).shape
             } else {
-                cursor_style
+                cursor_style.shape
             }
         };
 
@@ -1432,7 +1452,7 @@ impl<T> Term<T> {
         RenderableCursor {
             text_color,
             cursor_color,
-            key: CursorKey { style: cursor_style, is_wide },
+            key: CursorKey { shape: cursor_shape, is_wide },
             point,
             rendered: false,
         }
@@ -2098,6 +2118,9 @@ impl<T: EventListener> Handler for Term<T> {
         // Preserve vi mode across resets.
         self.mode &= TermMode::VI;
         self.mode.insert(TermMode::default());
+
+        let blinking = self.cursor_style().blinking;
+        self.event_proxy.send_event(Event::CursorBlinkingChange(blinking));
     }
 
     #[inline]
@@ -2199,7 +2222,9 @@ impl<T: EventListener> Handler for Term<T> {
             ansi::Mode::DECCOLM => self.deccolm(),
             ansi::Mode::Insert => self.mode.insert(TermMode::INSERT),
             ansi::Mode::BlinkingCursor => {
-                trace!("... unimplemented mode");
+                let style = self.cursor_style.get_or_insert(self.default_cursor_style);
+                style.blinking = true;
+                self.event_proxy.send_event(Event::CursorBlinkingChange(true));
             },
         }
     }
@@ -2239,7 +2264,9 @@ impl<T: EventListener> Handler for Term<T> {
             ansi::Mode::DECCOLM => self.deccolm(),
             ansi::Mode::Insert => self.mode.remove(TermMode::INSERT),
             ansi::Mode::BlinkingCursor => {
-                trace!("... unimplemented mode");
+                let style = self.cursor_style.get_or_insert(self.default_cursor_style);
+                style.blinking = false;
+                self.event_proxy.send_event(Event::CursorBlinkingChange(false));
             },
         }
     }
@@ -2296,6 +2323,18 @@ impl<T: EventListener> Handler for Term<T> {
     fn set_cursor_style(&mut self, style: Option<CursorStyle>) {
         trace!("Setting cursor style {:?}", style);
         self.cursor_style = style;
+
+        // Notify UI about blinking changes.
+        let blinking = style.unwrap_or(self.default_cursor_style).blinking;
+        self.event_proxy.send_event(Event::CursorBlinkingChange(blinking));
+    }
+
+    #[inline]
+    fn set_cursor_shape(&mut self, shape: CursorShape) {
+        trace!("Setting cursor shape {:?}", shape);
+
+        let style = self.cursor_style.get_or_insert(self.default_cursor_style);
+        style.shape = shape;
     }
 
     #[inline]
diff --git a/docs/escape_support.md b/docs/escape_support.md
index f1a0337c..d7c36d33 100644
--- a/docs/escape_support.md
+++ b/docs/escape_support.md
@@ -68,7 +68,7 @@ brevity.
 | `CSI m`    | PARTIAL     | Only singular straight underlines are supported   |
 | `CSI n`    | IMPLEMENTED |                                                   |
 | `CSI P`    | IMPLEMENTED |                                                   |
-| `CSI SP q` | PARTIAL     | No blinking support                               |
+| `CSI SP q` | IMPLEMENTED |                                                   |
 | `CSI r`    | IMPLEMENTED |                                                   |
 | `CSI S`    | IMPLEMENTED |                                                   |
 | `CSI s`    | IMPLEMENTED |                                                   |