Display manages window, renderer, rasterizer

This is part of an ongoing decoupling effort across the codebase and
tidying effort in main.rs. Everything to do with showing the window with
a grid of characters is now managed by the `Display` type. It owns the
window, the font rasterizer, and the renderer. The only info needed from
it are dimensions of characters and the window itself for sizing the
terminal properly. Additionally, the I/O loop has access to wake it up
when new data arrives.

9 files changed, 421 insertions, 280 deletions

diff --git a/src/cli.rs b/src/cli.rs
index b61d1054..15bd57c5 100644
--- a/src/cli.rs
+++ b/src/cli.rs
@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 use std::env;
-use alacritty::index::{Line, Column};
+use index::{Line, Column};
 
 /// Options specified on the command line
 pub struct Options {
diff --git a/src/display.rs b/src/display.rs
new file mode 100644
index 00000000..cfe684c0
--- /dev/null
+++ b/src/display.rs
@@ -0,0 +1,246 @@
+// Copyright 2016 Joe Wilm, The Alacritty Project Contributors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! The display subsystem including window management, font rasterization, and
+//! GPU drawing.
+use std::sync::mpsc;
+
+use parking_lot::{MutexGuard};
+
+use font;
+use Rgb;
+use ansi::Color;
+use cli;
+use config::Config;
+use meter::Meter;
+use renderer::{GlyphCache, QuadRenderer};
+use term::{Term, SizeInfo};
+
+use window::{self, Size, Pixels, Window, SetInnerSize};
+
+/// The display wraps a window, font rasterizer, and GPU renderer
+pub struct Display<F> {
+    window: Window,
+    renderer: QuadRenderer,
+    glyph_cache: GlyphCache,
+    render_timer: bool,
+    rx: mpsc::Receiver<(u32, u32)>,
+    tx: mpsc::Sender<(u32, u32)>,
+    meter: Meter,
+    resize_callback: Option<F>,
+    size_info: SizeInfo,
+}
+
+/// Can wakeup the render loop from other threads
+pub struct Notifier(window::Proxy);
+
+impl Notifier {
+    pub fn notify(&self) {
+        self.0.wakeup_event_loop();
+    }
+}
+
+impl<F> Display<F>
+    where F: Fn(&SizeInfo)
+{
+    pub fn notifier(&self) -> Notifier {
+        Notifier(self.window.create_window_proxy())
+    }
+
+    pub fn update_config(&mut self, config: &Config) {
+        self.renderer.update_config(config);
+        self.render_timer = config.render_timer();
+    }
+
+    /// Provide a callback to be invoked then the display changes size.
+    pub fn set_resize_callback(&mut self, callback: F) {
+        self.resize_callback = Some(callback);
+    }
+
+    /// Get size info about the display
+    pub fn size(&self) -> &SizeInfo {
+        &self.size_info
+    }
+
+    pub fn new(
+        config: &Config,
+        options: &cli::Options,
+    ) -> Result<Display<F>, window::Error> {
+        // Extract some properties from config
+        let font = config.font();
+        let dpi = config.dpi();
+        let render_timer = config.render_timer();
+
+        // Create the window where Alacritty will be displayed
+        let mut window = match Window::new() {
+            Ok(window) => window,
+            Err(err) => die!("{}", err)
+        };
+
+        // get window properties for initializing the other subsytems
+        let size = window.inner_size_pixels().unwrap();
+        let dpr = window.hidpi_factor();
+
+        println!("device_pixel_ratio: {}", dpr);
+
+        let rasterizer = font::Rasterizer::new(dpi.x(), dpi.y(), dpr);
+
+        // Create renderer
+        let mut renderer = QuadRenderer::new(&config, size);
+
+        // Initialize glyph cache
+        let glyph_cache = {
+            println!("Initializing glyph cache");
+            let init_start = ::std::time::Instant::now();
+
+            let cache = renderer.with_loader(|mut api| {
+                GlyphCache::new(rasterizer, &config, &mut api)
+            });
+
+            let stop = init_start.elapsed();
+            let stop_f = stop.as_secs() as f64 + stop.subsec_nanos() as f64 / 1_000_000_000f64;
+            println!("Finished initializing glyph cache in {}", stop_f);
+
+            cache
+        };
+
+        // Need font metrics to resize the window properly. This suggests to me the
+        // font metrics should be computed before creating the window in the first
+        // place so that a resize is not needed.
+        let metrics = glyph_cache.font_metrics();
+        let cell_width = (metrics.average_advance + font.offset().x() as f64) as u32;
+        let cell_height = (metrics.line_height + font.offset().y() as f64) as u32;
+
+        // Resize window to specified dimensions
+        let width = cell_width * options.columns_u32() + 4;
+        let height = cell_height * options.lines_u32() + 4;
+        let size = Size { width: Pixels(width), height: Pixels(height) };
+        println!("set_inner_size: {}", size);
+
+        window.set_inner_size(size);
+        renderer.resize(*size.width as _, *size.height as _);
+        println!("Cell Size: ({} x {})", cell_width, cell_height);
+
+        let size_info = SizeInfo {
+            width: *size.width as f32,
+            height: *size.height as f32,
+            cell_width: cell_width as f32,
+            cell_height: cell_height as f32
+        };
+
+        // Channel for resize events
+        //
+        // macOS has a callback for getting resize events, the channel is used
+        // to queue resize events until the next draw call. Unfortunately, it
+        // seems that the event loop is blocked until the window is done
+        // resizing. If any drawing were to happen during a resize, it would
+        // need to be in the callback.
+        let (tx, rx) = mpsc::channel();
+
+        let mut display = Display {
+            window: window,
+            renderer: renderer,
+            glyph_cache: glyph_cache,
+            render_timer: render_timer,
+            tx: tx,
+            rx: rx,
+            meter: Meter::new(),
+            resize_callback: None,
+            size_info: size_info,
+        };
+
+        let resize_tx = display.resize_channel();
+        let proxy = display.window.create_window_proxy();
+        display.window.set_resize_callback(move |width, height| {
+            let _ = resize_tx.send((width, height));
+            proxy.wakeup_event_loop();
+        });
+
+        Ok(display)
+    }
+
+    #[inline]
+    pub fn resize_channel(&self) -> mpsc::Sender<(u32, u32)> {
+        self.tx.clone()
+    }
+
+    pub fn window(&self) -> &Window {
+        &self.window
+    }
+
+    /// Draw the screen
+    ///
+    /// A reference to Term whose state is being drawn must be provided.
+    ///
+    /// This call may block if vsync is enabled
+    pub fn draw(&mut self, mut terminal: MutexGuard<Term>, config: &Config) {
+        // This is a hack since sometimes we get stuck waiting for events
+        // in the main loop otherwise.
+        //
+        // TODO figure out why this is necessary
+        self.window.clear_wakeup_flag();
+
+        // Clear dirty flag
+        terminal.dirty = false;
+
+        // Resize events new_size and are handled outside the poll_events
+        // iterator. This has the effect of coalescing multiple resize
+        // events into one.
+        let mut new_size = None;
+
+        // Check for any out-of-band resize events (mac only)
+        while let Ok(sz) = self.rx.try_recv() {
+            new_size = Some(sz);
+        }
+
+        // Receive any resize events; only call gl::Viewport on last
+        // available
+        if let Some((w, h)) = new_size.take() {
+            terminal.resize(w as f32, h as f32);
+            let size = terminal.size_info();
+            self.resize_callback.as_ref()
+                .map(|func| func(&size));
+            self.renderer.resize(w as i32, h as i32);
+        }
+
+        {
+            let glyph_cache = &mut self.glyph_cache;
+            // Draw grid
+            {
+                let _sampler = self.meter.sampler();
+
+                let size_info = terminal.size_info().clone();
+                self.renderer.with_api(config, &size_info, |mut api| {
+                    api.clear();
+
+                    // Draw the grid
+                    api.render_cells(terminal.renderable_cells(), glyph_cache);
+                });
+            }
+
+            // Draw render timer
+            if self.render_timer {
+                let timing = format!("{:.3} usec", self.meter.average());
+                let color = Color::Spec(Rgb { r: 0xd5, g: 0x4e, b: 0x53 });
+                self.renderer.with_api(config, terminal.size_info(), |mut api| {
+                    api.render_string(&timing[..], glyph_cache, &color);
+                });
+            }
+        }
+
+        // Unlock the terminal mutex
+        drop(terminal);
+        self.window.swap_buffers().unwrap();
+    }
+}
diff --git a/src/event.rs b/src/event.rs
index 900a0fb1..2a27dd61 100644
--- a/src/event.rs
+++ b/src/event.rs
@@ -5,6 +5,7 @@ use std::sync::{Arc, mpsc};
 use serde_json as json;
 
 use glutin;
+
 use window::Window;
 
 use input;
diff --git a/src/event_loop.rs b/src/event_loop.rs
index c2c5ce69..70aa4acb 100644
--- a/src/event_loop.rs
+++ b/src/event_loop.rs
@@ -10,14 +10,11 @@ use mio::{self, Events, PollOpt, Ready};
 use mio::unix::EventedFd;
 
 use ansi;
+use display;
 use term::Term;
 use util::thread;
 use sync::FairMutex;
 
-use window;
-
-use super::Flag;
-
 /// Messages that may be sent to the `EventLoop`
 #[derive(Debug)]
 pub enum Msg {
@@ -35,8 +32,7 @@ pub struct EventLoop<Io> {
     rx: mio::channel::Receiver<Msg>,
     tx: mio::channel::Sender<Msg>,
     terminal: Arc<FairMutex<Term>>,
-    proxy: window::Proxy,
-    signal_flag: Flag,
+    display: display::Notifier,
     ref_test: bool,
 }
 
@@ -131,8 +127,7 @@ impl<Io> EventLoop<Io>
     /// Create a new event loop
     pub fn new(
         terminal: Arc<FairMutex<Term>>,
-        proxy: window::Proxy,
-        signal_flag: Flag,
+        display: display::Notifier,
         pty: Io,
         ref_test: bool,
     ) -> EventLoop<Io> {
@@ -143,8 +138,7 @@ impl<Io> EventLoop<Io>
             tx: tx,
             rx: rx,
             terminal: terminal,
-            proxy: proxy,
-            signal_flag: signal_flag,
+            display: display,
             ref_test: ref_test,
         }
     }
@@ -196,14 +190,7 @@ impl<Io> EventLoop<Io>
 
                     terminal.dirty = true;
 
-                    // Only wake up the event loop if it hasn't already been
-                    // signaled. This is a really important optimization because
-                    // waking up the event loop redundantly burns *a lot* of
-                    // cycles.
-                    if !self.signal_flag.get() {
-                        self.proxy.wakeup_event_loop();
-                        self.signal_flag.set(true);
-                    }
+                    self.display.notify();
                 },
                 Err(err) => {
                     match err.kind() {
diff --git a/src/lib.rs b/src/lib.rs
index cd4f382e..9903f591 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -49,7 +49,9 @@ extern crate bitflags;
 pub mod macros;
 
 pub mod ansi;
+pub mod cli;
 pub mod config;
+pub mod display;
 pub mod event;
 pub mod event_loop;
 pub mod grid;
@@ -63,9 +65,6 @@ pub mod tty;
 pub mod util;
 pub mod window;
 
-use std::sync::Arc;
-use std::sync::atomic::{AtomicBool, Ordering};
-
 pub use grid::Grid;
 pub use term::Term;
 
@@ -80,21 +79,3 @@ pub mod gl {
     #![allow(non_upper_case_globals)]
     include!(concat!(env!("OUT_DIR"), "/gl_bindings.rs"));
 }
-
-#[derive(Clone)]
-pub struct Flag(pub Arc<AtomicBool>);
-impl Flag {
-    pub fn new(initial_value: bool) -> Flag {
-        Flag(Arc::new(AtomicBool::new(initial_value)))
-    }
-
-    #[inline]
-    pub fn get(&self) -> bool {
-        self.0.load(Ordering::Acquire)
-    }
-
-    #[inline]
-    pub fn set(&self, value: bool) {
-        self.0.store(value, Ordering::Release)
-    }
-}
diff --git a/src/main.rs b/src/main.rs
index 1c1397d0..0fba05a6 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -42,25 +42,20 @@ extern crate vte;
 #[macro_use]
 extern crate bitflags;
 
+use std::error::Error;
 use std::sync::{mpsc, Arc};
-use std::sync::atomic::Ordering;
+use std::rc::Rc;
 
-use parking_lot::{MutexGuard};
-
-use alacritty::Flag;
-use alacritty::Rgb;
+use alacritty::cli;
 use alacritty::config::{self, Config};
+use alacritty::display::{self, Display};
 use alacritty::event;
 use alacritty::event_loop::EventLoop;
 use alacritty::input;
-use alacritty::meter::Meter;
-use alacritty::renderer::{QuadRenderer, GlyphCache};
 use alacritty::sync::FairMutex;
-use alacritty::term::{self, Term};
-use alacritty::tty::{self, Pty, process_should_exit};
-use alacritty::window::{self, Window, SetInnerSize, Pixels, Size};
+use alacritty::term::{Term};
+use alacritty::tty::{self, process_should_exit};
 
-mod cli;
 
 fn main() {
     // Load configuration
@@ -86,7 +81,11 @@ fn main() {
     let options = cli::Options::load();
 
     // Run alacritty
-    run(config, options);
+    if let Err(err) = run(config, options) {
+        die!("{}", err);
+    }
+
+    println!("Goodbye");
 }
 
 /// Run Alacritty
@@ -156,124 +155,59 @@ fn main() {
 ///
 /// instead of the 200 line monster it currently is.
 ///
-fn run(config: Config, options: cli::Options) {
-
-
-    // Extract some properties from config
-    let font = config.font();
-    let dpi = config.dpi();
-    let render_timer = config.render_timer();
-
-    // Create the window where Alacritty will be displayed
-    let mut window = match Window::new() {
-        Ok(window) => window,
-        Err(err) => die!("{}", err)
-    };
-
-    // get window properties for initializing the other subsytems
-    let size = window.inner_size_pixels().unwrap();
-    let dpr = window.hidpi_factor();
-
-    println!("device_pixel_ratio: {}", dpr);
-
-    let rasterizer = font::Rasterizer::new(dpi.x(), dpi.y(), dpr);
-
-    // Create renderer
-    let mut renderer = QuadRenderer::new(&config, size);
-
-    // Initialize glyph cache
-    let glyph_cache = {
-        println!("Initializing glyph cache");
-        let init_start = ::std::time::Instant::now();
-
-        let cache = renderer.with_loader(|mut api| {
-            GlyphCache::new(rasterizer, &config, &mut api)
-        });
-
-        let stop = init_start.elapsed();
-        let stop_f = stop.as_secs() as f64 + stop.subsec_nanos() as f64 / 1_000_000_000f64;
-        println!("Finished initializing glyph cache in {}", stop_f);
-
-        cache
-    };
-
-    // Need font metrics to resize the window properly. This suggests to me the
-    // font metrics should be computed before creating the window in the first
-    // place so that a resize is not needed.
-    let metrics = glyph_cache.font_metrics();
-    let cell_width = (metrics.average_advance + font.offset().x() as f64) as u32;
-    let cell_height = (metrics.line_height + font.offset().y() as f64) as u32;
-
-    // Resize window to specified dimensions
-    let width = cell_width * options.columns_u32() + 4;
-    let height = cell_height * options.lines_u32() + 4;
-    let size = Size { width: Pixels(width), height: Pixels(height) };
-    println!("set_inner_size: {}", size);
-
-    window.set_inner_size(size);
-    renderer.resize(*size.width as _, *size.height as _);
-
-    println!("Cell Size: ({} x {})", cell_width, cell_height);
-
-    let size = term::SizeInfo {
-        width: *size.width as f32,
-        height: *size.height as f32,
-        cell_width: cell_width as f32,
-        cell_height: cell_height as f32
-    };
-
-    let terminal = Term::new(size);
-    let pty = tty::new(size.lines(), size.cols());
-    pty.resize(size.lines(), size.cols(), size.width as usize, size.height as usize);
-    let pty_io = pty.reader();
-
-    let (tx, rx) = mpsc::channel();
-
-    let signal_flag = Flag::new(false);
-
-    let terminal = Arc::new(FairMutex::new(terminal));
-
-    // Setup the rsize callback for osx
-    let terminal_ref = terminal.clone();
-    let signal_flag_ref = signal_flag.clone();
-    let proxy = window.create_window_proxy();
-    let tx2 = tx.clone();
-    window.set_resize_callback(move |width, height| {
-        let _ = tx2.send((width, height));
-        if !signal_flag_ref.0.swap(true, Ordering::AcqRel) {
-           // We raised the signal flag
-            let mut terminal = terminal_ref.lock();
-            terminal.dirty = true;
-            proxy.wakeup_event_loop();
-        }
+fn run(config: Config, options: cli::Options) -> Result<(), Box<Error>> {
+    // Create a display.
+    //
+    // The display manages a window and can draw the terminal
+    let mut display = Display::new(&config, &options)?;
+
+    // Create the terminal
+    //
+    // This object contains all of the state about what's being displayed. It's
+    // wrapped in a clonable mutex since both the I/O loop and display need to
+    // access it.
+    let terminal = Arc::new(FairMutex::new(Term::new(display.size().to_owned())));
+
+    // Create the pty
+    //
+    // The pty forks a process to run the shell on the slave side of the
+    // pseudoterminal. A file descriptor for the master side is retained for
+    // reading/writing to the shell.
+    let pty = Rc::new(tty::new(display.size()));
+
+    // When the display is resized, inform the kernel of changes to pty
+    // dimensions.
+    //
+    // TODO: The Rc on pty is needed due to a borrowck error here. The borrow
+    // checker says that `pty` is still borrowed when it is dropped at the end
+    // of the `run` function.
+    let pty_ref = pty.clone();
+    display.set_resize_callback(move |size| {
+        pty_ref.resize(size);
     });
 
+    // Create the pseudoterminal I/O loop
+    //
+    // pty I/O is ran on another thread as to not occupy cycles used by the
+    // renderer and input processing. Note that access to the terminal state is
+    // synchronized since the I/O loop updates the state, and the display
+    // consumes it periodically.
     let event_loop = EventLoop::new(
         terminal.clone(),
-        window.create_window_proxy(),
-        signal_flag.clone(),
-        pty_io,
+        display.notifier(),
+        pty.reader(),
         options.ref_test,
     );
 
     let loop_tx = event_loop.channel();
     let event_loop_handle = event_loop.spawn(None);
 
-    // Wraps a renderer and gives simple draw() api.
-    let mut display = Display::new(
-        &window,
-        renderer,
-        glyph_cache,
-        render_timer,
-        rx,
-        pty
-    );
-
     // Event processor
+    let resize_tx = display.resize_channel();
     let mut processor = event::Processor::new(
         input::LoopNotifier(loop_tx),
         terminal.clone(),
-        tx,
+        resize_tx,
         &config,
         options.ref_test,
     );
@@ -284,28 +218,26 @@ fn run(config: Config, options: cli::Options) {
     let _config_reloader = config.path().map(|path| {
         config::Watcher::new(path, ConfigHandler {
             tx: config_tx,
-            window: window.create_window_proxy(),
+            loop_kicker: display.notifier(),
         })
     });
 
     // Main loop
-    let mut force_draw;
+    let mut config_updated = false;
     loop {
-        force_draw = false;
         // Wait for something to happen
-        processor.process_events(&window);
+        processor.process_events(display.window());
 
         // Handle config reloads
         if let Ok(config) = config_rx.try_recv() {
-            force_draw = true;
+            config_updated = true;
             display.update_config(&config);
             processor.update_config(&config);
         }
 
         // Maybe draw the terminal
         let terminal = terminal.lock();
-        signal_flag.set(false);
-        if force_draw || terminal.dirty {
+        if terminal.dirty || config_updated {
             display.draw(terminal, &config);
         }
 
@@ -317,16 +249,19 @@ fn run(config: Config, options: cli::Options) {
 
     // FIXME need file watcher to work with custom delegates before
     //       joining config reloader is possible
+    //
+    // HELP I don't know what I meant in the above fixme
     // config_reloader.join().ok();
 
     // shutdown
     event_loop_handle.join().ok();
-    println!("Goodbye");
+
+    Ok(())
 }
 
 struct ConfigHandler {
     tx: mpsc::Sender<config::Config>,
-    window: window::Proxy,
+    loop_kicker: display::Notifier,
 }
 
 impl config::OnConfigReload for ConfigHandler {
@@ -336,100 +271,7 @@ impl config::OnConfigReload for ConfigHandler {
             return;
         }
 
-        self.window.wakeup_event_loop();
+        self.loop_kicker.notify();
     }
 }
 
-struct Display<'a> {
-    window: &'a Window,
-    renderer: QuadRenderer,
-    glyph_cache: GlyphCache,
-    render_timer: bool,
-    rx: mpsc::Receiver<(u32, u32)>,
-    meter: Meter,
-    pty: Pty,
-}
-
-impl<'a> Display<'a> {
-    pub fn update_config(&mut self, config: &Config) {
-        self.renderer.update_config(config);
-        self.render_timer = config.render_timer();
-    }
-
-    pub fn new(
-        window: &Window,
-        renderer: QuadRenderer,
-        glyph_cache: GlyphCache,
-        render_timer: bool,
-        rx: mpsc::Receiver<(u32, u32)>,
-        pty: Pty
-    ) -> Display {
-        Display {
-            window: window,
-            renderer: renderer,
-            glyph_cache: glyph_cache,
-            render_timer: render_timer,
-            rx: rx,
-            meter: Meter::new(),
-            pty: pty,
-        }
-    }
-
-    /// Draw the screen
-    ///
-    /// A reference to Term whose state is being drawn must be provided.
-    ///
-    /// This call may block if vsync is enabled
-    pub fn draw(&mut self, mut terminal: MutexGuard<Term>, config: &Config) {
-        terminal.dirty = false;
-
-        // Resize events new_size and are handled outside the poll_events
-        // iterator. This has the effect of coalescing multiple resize
-        // events into one.
-        let mut new_size = None;
-
-
-        // Check for any out-of-band resize events (mac only)
-        while let Ok(sz) = self.rx.try_recv() {
-            new_size = Some(sz);
-        }
-
-        // Receive any resize events; only call gl::Viewport on last
-        // available
-        if let Some((w, h)) = new_size.take() {
-            terminal.resize(w as f32, h as f32);
-            let size = terminal.size_info();
-            self.pty.resize(size.lines(), size.cols(), w as _, h as _);
-            self.renderer.resize(w as i32, h as i32);
-        }
-
-        {
-            let glyph_cache = &mut self.glyph_cache;
-            // Draw grid
-            {
-                let _sampler = self.meter.sampler();
-
-                let size_info = terminal.size_info().clone();
-                self.renderer.with_api(config, &size_info, |mut api| {
-                    api.clear();
-
-                    // Draw the grid
-                    api.render_cells(terminal.renderable_cells(), glyph_cache);
-                });
-            }
-
-            // Draw render timer
-            if self.render_timer {
-                let timing = format!("{:.3} usec", self.meter.average());
-                let color = alacritty::ansi::Color::Spec(Rgb { r: 0xd5, g: 0x4e, b: 0x53 });
-                self.renderer.with_api(config, terminal.size_info(), |mut api| {
-                    api.render_string(&timing[..], glyph_cache, &color);
-                });
-            }
-        }
-
-        // Unlock the terminal mutex
-        drop(terminal);
-        self.window.swap_buffers().unwrap();
-    }
-}
diff --git a/src/term/mod.rs b/src/term/mod.rs
index 979999a9..da5683e0 100644
--- a/src/term/mod.rs
+++ b/src/term/mod.rs
@@ -23,6 +23,20 @@ use grid::{Grid, ClearRegion};
 use index::{Cursor, Column, Line};
 use ansi::{Color, NamedColor};
 
+use tty::ToWinsize;
+use libc::{self, winsize};
+
+impl<'a> ToWinsize for &'a SizeInfo {
+    fn to_winsize(&self) -> winsize {
+        winsize {
+            ws_row: self.lines().0 as libc::c_ushort,
+            ws_col: self.cols().0 as libc::c_ushort,
+            ws_xpixel: self.width as libc::c_ushort,
+            ws_ypixel: self.height as libc::c_ushort,
+        }
+    }
+}
+
 pub mod cell;
 pub use self::cell::Cell;
 
diff --git a/src/tty.rs b/src/tty.rs
index fddb4d99..7071bad3 100644
--- a/src/tty.rs
+++ b/src/tty.rs
@@ -23,8 +23,6 @@ use std::ptr;
 
 use libc::{self, winsize, c_int, pid_t, WNOHANG, WIFEXITED, WEXITSTATUS, SIGCHLD};
 
-use index::{Line, Column};
-
 /// Process ID of child process
 ///
 /// Necessary to put this in static storage for `sigchld` to have access
@@ -238,8 +236,10 @@ fn execsh() -> ! {
 }
 
 /// Create a new tty and return a handle to interact with it.
-pub fn new(lines: Line, cols: Column) -> Pty {
-    let (master, slave) = openpty(lines.0 as _, cols.0 as _);
+pub fn new<T: ToWinsize>(size: T) -> Pty {
+    let win = size.to_winsize();
+
+    let (master, slave) = openpty(win.ws_row as _, win.ws_col as _);
 
     match fork() {
         Relation::Child => {
@@ -282,7 +282,9 @@ pub fn new(lines: Line, cols: Column) -> Pty {
                 set_nonblocking(master);
             }
 
-            Pty { fd: master }
+            let pty = Pty { fd: master };
+            pty.resize(size);
+            pty
         }
     }
 }
@@ -301,15 +303,12 @@ impl Pty {
         }
     }
 
-    pub fn resize(&self, lines: Line, cols: Column, px_x: usize, px_y: usize) {
-        let lines = lines.0;
-        let cols = cols.0;
-        let win = winsize {
-            ws_row: lines as libc::c_ushort,
-            ws_col: cols as libc::c_ushort,
-            ws_xpixel: px_x as libc::c_ushort,
-            ws_ypixel: px_y as libc::c_ushort,
-        };
+    /// Resize the pty
+    ///
+    /// Tells the kernel that the window size changed with the new pixel
+    /// dimensions and line/column counts.
+    pub fn resize<T: ToWinsize>(&self, size: T) {
+        let win = size.to_winsize();
 
         let res = unsafe {
             libc::ioctl(self.fd, libc::TIOCSWINSZ, &win as *const _)
@@ -321,6 +320,12 @@ impl Pty {
     }
 }
 
+/// Types that can produce a `libc::winsize`
+pub trait ToWinsize {
+    /// Get a `libc::winsize`
+    fn to_winsize(&self) -> winsize;
+}
+
 unsafe fn set_nonblocking(fd: c_int) {
     use libc::{fcntl, F_SETFL, F_GETFL, O_NONBLOCK};
 
diff --git a/src/window.rs b/src/window.rs
index 4d8a0c02..f9f2050c 100644
--- a/src/window.rs
+++ b/src/window.rs
@@ -11,6 +11,8 @@
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.
+use std::sync::Arc;
+use std::sync::atomic::{AtomicBool, Ordering};
 use std::convert::From;
 use std::fmt::{self, Display};
 use std::ops::Deref;
@@ -55,10 +57,17 @@ type Result<T> = ::std::result::Result<T, Error>;
 /// Wraps the underlying windowing library to provide a stable API in Alacritty
 pub struct Window {
     glutin_window: glutin::Window,
+
+    /// This flag allows calls to wakeup_event_loop to be coalesced. Waking the
+    /// event loop is potentially very slow (and indeed is on X11).
+    flag: Flag
 }
 
 /// Threadsafe APIs for the window
-pub struct Proxy(glutin::WindowProxy);
+pub struct Proxy {
+    inner: glutin::WindowProxy,
+    flag: Flag,
+}
 
 /// Information about where the window is being displayed
 ///
@@ -89,6 +98,46 @@ pub struct Pixels<T>(pub T);
 #[derive(Debug, Copy, Clone)]
 pub struct Points<T>(pub T);
 
+/// A wrapper around glutin's WaitEventsIterator that clears the wakeup
+/// optimization flag on drop.
+pub struct WaitEventsIterator<'a> {
+    inner: glutin::WaitEventsIterator<'a>,
+    flag: Flag
+}
+
+impl<'a> Iterator for WaitEventsIterator<'a> {
+    type Item = glutin::Event;
+
+    #[inline]
+    fn next(&mut self) -> Option<Self::Item> {
+        self.inner.next()
+    }
+}
+
+impl<'a> Drop for WaitEventsIterator<'a> {
+    fn drop(&mut self) {
+        self.flag.set(false);
+    }
+}
+
+#[derive(Clone)]
+pub struct Flag(pub Arc<AtomicBool>);
+impl Flag {
+    pub fn new(initial_value: bool) -> Flag {
+        Flag(Arc::new(AtomicBool::new(initial_value)))
+    }
+
+    #[inline]
+    pub fn get(&self) -> bool {
+        self.0.load(Ordering::Acquire)
+    }
+
+    #[inline]
+    pub fn set(&self, value: bool) {
+        self.0.store(value, Ordering::Release)
+    }
+}
+
 pub trait ToPoints {
     fn to_points(&self, scale: f32) -> Size<Points<u32>>;
 }
@@ -216,6 +265,7 @@ impl Window {
 
         Ok(Window {
             glutin_window: window,
+            flag: Flag::new(false),
         })
     }
 
@@ -256,7 +306,10 @@ impl Window {
 
     #[inline]
     pub fn create_window_proxy(&self) -> Proxy {
-        Proxy(self.glutin_window.create_window_proxy())
+        Proxy {
+            inner: self.glutin_window.create_window_proxy(),
+            flag: self.flag.clone(),
+        }
     }
 
     #[inline]
@@ -267,11 +320,17 @@ impl Window {
     }
 
     /// Block waiting for events
-    ///
-    /// FIXME should return our own type
     #[inline]
-    pub fn wait_events(&self) -> glutin::WaitEventsIterator {
-        self.glutin_window.wait_events()
+    pub fn wait_events(&self) -> WaitEventsIterator {
+        WaitEventsIterator {
+            inner: self.glutin_window.wait_events(),
+            flag: self.flag.clone()
+        }
+    }
+
+    /// Clear the wakeup optimization flag
+    pub fn clear_wakeup_flag(&self) {
+        self.flag.set(false);
     }
 
     /// Block waiting for events
@@ -289,7 +348,13 @@ impl Proxy {
     /// This is useful for triggering a draw when the renderer would otherwise
     /// be waiting on user input.
     pub fn wakeup_event_loop(&self) {
-        self.0.wakeup_event_loop();
+        // Only wake up the window event loop if it hasn't already been
+        // signaled. This is a really important optimization because waking up
+        // the event loop redundantly burns *a lot* of cycles.
+        if !self.flag.get() {
+            self.inner.wakeup_event_loop();
+            self.flag.set(true);
+        }
     }
 }