From 45564f952b4aa8082393118a6ab118c211a6ef79 Mon Sep 17 00:00:00 2001
From: Emil Ernerfeldt <emilernerfeldt@gmail.com>
Date: Sun, 3 May 2020 13:28:47 +0200
Subject: [PATCH] Kinetic windows

---
 emigui/README.md                  |   2 +-
 emigui/src/containers/floating.rs |  20 +++-
 emigui/src/context.rs             |  31 ++++-
 emigui/src/emigui.rs              |  47 +-------
 emigui/src/input.rs               | 193 ++++++++++++++++++++++++++++++
 emigui/src/lib.rs                 |   4 +
 emigui/src/movement_tracker.rs    | 120 +++++++++++++++++++
 emigui/src/texture_atlas.rs       |   5 +-
 emigui/src/types.rs               | 141 +---------------------
 emigui/src/widgets.rs             |   4 +-
 example_glium/src/main.rs         |  34 +++---
 example_wasm/src/lib.rs           |  26 ++--
 12 files changed, 398 insertions(+), 229 deletions(-)
 create mode 100644 emigui/src/input.rs
 create mode 100644 emigui/src/movement_tracker.rs

diff --git a/emigui/README.md b/emigui/README.md
index effb9611..97928b7d 100644
--- a/emigui/README.md
+++ b/emigui/README.md
@@ -12,7 +12,7 @@ This is the core library crate Emigui. It is fully platform independent without
 * [x] Collapsing header region
 * [x] Tooltip
 * [x] Movable/resizable windows
-    * [ ] Kinetic windows
+    * [x] Kinetic windows
     * [ ] BUG FIX: Don't catch clicks on closed windows
 * [ ] Scroll areas
     * [x] Vertical scrolling
diff --git a/emigui/src/containers/floating.rs b/emigui/src/containers/floating.rs
index 028756f9..e6d176e7 100644
--- a/emigui/src/containers/floating.rs
+++ b/emigui/src/containers/floating.rs
@@ -14,6 +14,10 @@ pub(crate) struct State {
 
     /// Last know size. Used for catching clicks.
     pub size: Vec2,
+
+    /// You can throw a Floating thing. It's fun.
+    #[serde(skip)]
+    pub vel: Vec2,
 }
 
 // TODO: rename Floating to something else. Area?
@@ -56,6 +60,7 @@ impl Floating {
                 let state = State {
                     pos: default_pos,
                     size: Vec2::zero(),
+                    vel: Vec2::zero(),
                 };
                 (state, true)
             }
@@ -75,8 +80,21 @@ impl Floating {
         let clip_rect = Rect::everything();
         let move_interact = ctx.interact(layer, &clip_rect, &rect, Some(id.with("move")));
 
+        let input = ctx.input();
         if move_interact.active {
-            state.pos += ctx.input().mouse_move;
+            state.pos += input.mouse_move;
+            state.vel = input.mouse_velocity;
+        } else {
+            let stop_speed = 20.0; // Pixels per second.
+            let friction_coeff = 1000.0; // Pixels per second squared.
+
+            let friction = friction_coeff * input.dt;
+            if friction > state.vel.length() || state.vel.length() < stop_speed {
+                state.vel = Vec2::zero();
+            } else {
+                state.vel -= friction * state.vel.normalized();
+                state.pos += state.vel * input.dt;
+            }
         }
 
         // Constrain to screen:
diff --git a/emigui/src/context.rs b/emigui/src/context.rs
index 44825368..63090332 100644
--- a/emigui/src/context.rs
+++ b/emigui/src/context.rs
@@ -10,8 +10,9 @@ pub struct Context {
     pub(crate) style: Mutex<Style>,
     pub(crate) fonts: Arc<Fonts>,
     /// Raw input from last frame. Use `input()` instead.
-    pub(crate) last_raw_input: RawInput,
+    last_raw_input: RawInput,
     pub(crate) input: GuiInput,
+    mouse_tracker: MovementTracker<Pos2>,
     memory: Mutex<Memory>,
     pub(crate) graphics: Mutex<GraphicLayers>,
 
@@ -29,6 +30,7 @@ impl Clone for Context {
             fonts: self.fonts.clone(),
             last_raw_input: self.last_raw_input.clone(),
             input: self.input.clone(),
+            mouse_tracker: self.mouse_tracker.clone(),
             memory: Mutex::new(self.memory.lock().clone()),
             graphics: Mutex::new(self.graphics.lock().clone()),
             output: Mutex::new(self.output.lock().clone()),
@@ -44,6 +46,7 @@ impl Context {
             fonts: Arc::new(Fonts::new(pixels_per_point)),
             last_raw_input: Default::default(),
             input: Default::default(),
+            mouse_tracker: MovementTracker::new(1000, 0.1),
             memory: Default::default(),
             graphics: Default::default(),
             output: Default::default(),
@@ -63,6 +66,11 @@ impl Context {
         &self.input
     }
 
+    /// Smoothed mouse velocity, in points per second
+    pub fn mouse_vel(&self) -> Vec2 {
+        self.mouse_tracker.velocity().unwrap_or_default()
+    }
+
     /// Raw input from last frame. Use `input()` instead.
     pub fn last_raw_input(&self) -> &RawInput {
         &self.last_raw_input
@@ -76,6 +84,10 @@ impl Context {
         *self.style.lock() = style;
     }
 
+    pub fn pixels_per_point(&self) -> f32 {
+        self.input.pixels_per_point
+    }
+
     /// Useful for pixel-perfect rendering
     pub fn round_to_pixel(&self, point: f32) -> f32 {
         (point * self.input.pixels_per_point).round() / self.input.pixels_per_point
@@ -89,10 +101,21 @@ impl Context {
         vec2(self.round_to_pixel(vec.x), self.round_to_pixel(vec.y))
     }
 
-    // TODO: move
-    pub fn begin_frame(&mut self, gui_input: GuiInput) {
+    pub fn begin_frame(&mut self, new_input: RawInput) {
+        if !self.last_raw_input.mouse_down || self.last_raw_input.mouse_pos.is_none() {
+            self.memory().active_id = None;
+        }
+
         self.used_ids.lock().clear();
-        self.input = gui_input;
+
+        if let Some(mouse_pos) = new_input.mouse_pos {
+            self.mouse_tracker.add(new_input.time, mouse_pos);
+        } else {
+            self.mouse_tracker.clear();
+        }
+        self.input = GuiInput::from_last_and_new(&self.last_raw_input, &new_input);
+        self.input.mouse_velocity = self.mouse_vel();
+        self.last_raw_input = new_input;
     }
 
     pub fn end_frame(&self) -> Output {
diff --git a/emigui/src/emigui.rs b/emigui/src/emigui.rs
index b3e1f6ff..c963a97a 100644
--- a/emigui/src/emigui.rs
+++ b/emigui/src/emigui.rs
@@ -12,7 +12,6 @@ struct Stats {
 /// Encapsulates input, layout and painting for ease of use.
 /// TODO: merge into Context
 pub struct Emigui {
-    last_input: RawInput,
     ctx: Arc<Context>,
     stats: Stats,
     mesher_options: MesherOptions,
@@ -21,7 +20,6 @@ pub struct Emigui {
 impl Emigui {
     pub fn new(pixels_per_point: f32) -> Emigui {
         Emigui {
-            last_input: Default::default(),
             ctx: Arc::new(Context::new(pixels_per_point)),
             stats: Default::default(),
             mesher_options: MesherOptions::default(),
@@ -37,18 +35,10 @@ impl Emigui {
     }
 
     pub fn begin_frame(&mut self, new_input: RawInput) {
-        if !self.last_input.mouse_down || self.last_input.mouse_pos.is_none() {
-            self.ctx.memory().active_id = None;
-        }
-
-        let gui_input = GuiInput::from_last_and_new(&self.last_input, &new_input);
-        self.last_input = new_input.clone(); // TODO: also stored in Context. Remove this one
-
         // TODO: avoid this clone
         let mut new_ctx = (*self.ctx).clone();
 
-        new_ctx.last_raw_input = new_input;
-        new_ctx.begin_frame(gui_input);
+        new_ctx.begin_frame(new_input);
         self.ctx = Arc::new(new_ctx);
     }
 
@@ -59,7 +49,7 @@ impl Emigui {
     }
 
     fn paint(&mut self) -> PaintBatches {
-        self.mesher_options.aa_size = 1.0 / self.last_input.pixels_per_point;
+        self.mesher_options.aa_size = 1.0 / self.ctx().pixels_per_point();
         let paint_commands = self.ctx.drain_paint_lists();
         let batches = mesh_paint_commands(&self.mesher_options, &self.ctx.fonts, paint_commands);
         self.stats = Default::default();
@@ -149,36 +139,3 @@ fn font_definitions_ui(font_definitions: &mut FontDefinitions, region: &mut Regi
         *font_definitions = crate::fonts::default_font_definitions();
     }
 }
-
-impl RawInput {
-    pub fn ui(&self, region: &mut Region) {
-        // TODO: simpler way to show values, e.g. `region.value("Mouse Pos:", self.mouse_pos);
-        // TODO: easily change default font!
-        region.add(label!("mouse_down: {}", self.mouse_down));
-        region.add(label!("mouse_pos: {:.1?}", self.mouse_pos));
-        region.add(label!("scroll_delta: {:?}", self.scroll_delta));
-        region.add(label!("screen_size: {:?}", self.screen_size));
-        region.add(label!("pixels_per_point: {}", self.pixels_per_point));
-        region.add(label!("time: {:.3} s", self.time));
-        region.add(label!("events: {:?}", self.events));
-        region.add(label!("dropped_files: {:?}", self.dropped_files));
-        region.add(label!("hovered_files: {:?}", self.hovered_files));
-    }
-}
-
-impl GuiInput {
-    pub fn ui(&self, region: &mut Region) {
-        region.add(label!("mouse_down: {}", self.mouse_down));
-        region.add(label!("mouse_pressed: {}", self.mouse_pressed));
-        region.add(label!("mouse_released: {}", self.mouse_released));
-        region.add(label!("mouse_pos: {:?}", self.mouse_pos));
-        region.add(label!("mouse_move: {:?}", self.mouse_move));
-        region.add(label!("scroll_delta: {:?}", self.scroll_delta));
-        region.add(label!("screen_size: {:?}", self.screen_size));
-        region.add(label!("pixels_per_point: {}", self.pixels_per_point));
-        region.add(label!("time: {}", self.time));
-        region.add(label!("events: {:?}", self.events));
-        region.add(label!("dropped_files: {:?}", self.dropped_files));
-        region.add(label!("hovered_files: {:?}", self.hovered_files));
-    }
-}
diff --git a/emigui/src/input.rs b/emigui/src/input.rs
new file mode 100644
index 00000000..83c359bf
--- /dev/null
+++ b/emigui/src/input.rs
@@ -0,0 +1,193 @@
+use crate::math::*;
+
+/// What the integration gives to the gui.
+/// All coordinates in emigui is in point/logical coordinates.
+#[derive(Clone, Debug, Default, Deserialize)]
+#[serde(default)]
+pub struct RawInput {
+    /// Is the button currently down?
+    pub mouse_down: bool,
+
+    /// Current position of the mouse in points.
+    pub mouse_pos: Option<Pos2>,
+
+    /// How many pixels the user scrolled
+    pub scroll_delta: Vec2,
+
+    /// Size of the screen in points.
+    pub screen_size: Vec2,
+
+    /// Also known as device pixel ratio, > 1 for HDPI screens.
+    pub pixels_per_point: f32,
+
+    /// Time in seconds. Relative to whatever. Used for animation.
+    pub time: f64,
+
+    /// Files has been dropped into the window.
+    pub dropped_files: Vec<std::path::PathBuf>,
+
+    /// Someone is threatening to drop these on us.
+    pub hovered_files: Vec<std::path::PathBuf>,
+
+    /// In-order events received this frame
+    pub events: Vec<Event>,
+}
+
+/// What emigui maintains
+#[derive(Clone, Debug, Default)]
+pub struct GuiInput {
+    // TODO: mouse: Mouse as separate
+    //
+    /// Is the button currently down?
+    /// true the frame when it is pressed,
+    /// false the frame it is released.
+    pub mouse_down: bool,
+
+    /// The mouse went from !down to down
+    pub mouse_pressed: bool,
+
+    /// The mouse went from down to !down
+    pub mouse_released: bool,
+
+    /// Current position of the mouse in points.
+    /// None for touch screens when finger is not down.
+    pub mouse_pos: Option<Pos2>,
+
+    /// How much the mouse moved compared to last frame, in points.
+    pub mouse_move: Vec2,
+
+    /// Current velocity of mouse cursor, if any.
+    pub mouse_velocity: Vec2,
+
+    /// How many pixels the user scrolled
+    pub scroll_delta: Vec2,
+
+    /// Size of the screen in points.
+    pub screen_size: Vec2,
+
+    /// Also known as device pixel ratio, > 1 for HDPI screens.
+    pub pixels_per_point: f32,
+
+    /// Time in seconds. Relative to whatever. Used for animation.
+    pub time: f64,
+
+    /// Time since last frame, in seconds.
+    pub dt: f32,
+
+    /// Files has been dropped into the window.
+    pub dropped_files: Vec<std::path::PathBuf>,
+
+    /// Someone is threatening to drop these on us.
+    pub hovered_files: Vec<std::path::PathBuf>,
+
+    /// In-order events received this frame
+    pub events: Vec<Event>,
+}
+
+#[derive(Clone, Debug, Eq, Ord, PartialEq, PartialOrd, Deserialize)]
+#[serde(rename_all = "snake_case")]
+pub enum Event {
+    Copy,
+    Cut,
+    /// Text input, e.g. via keyboard or paste action
+    Text(String),
+    Key {
+        key: Key,
+        pressed: bool,
+    },
+}
+
+#[derive(Clone, Debug, Eq, Ord, PartialEq, PartialOrd, Deserialize)]
+#[serde(rename_all = "snake_case")]
+pub enum Key {
+    Alt,
+    Backspace,
+    Control,
+    Delete,
+    Down,
+    End,
+    Escape,
+    Home,
+    Insert,
+    Left,
+    /// Windows key or Mac Command key
+    Logo,
+    PageDown,
+    PageUp,
+    Return,
+    Right,
+    Shift,
+    // Space,
+    Tab,
+    Up,
+}
+
+impl GuiInput {
+    pub fn from_last_and_new(last: &RawInput, new: &RawInput) -> GuiInput {
+        let mouse_move = new
+            .mouse_pos
+            .and_then(|new| last.mouse_pos.map(|last| new - last))
+            .unwrap_or_default();
+        let dt = (new.time - last.time) as f32;
+        let mut mouse_velocity = mouse_move / dt;
+        if !mouse_velocity.is_finite() {
+            mouse_velocity = Vec2::zero();
+        }
+        GuiInput {
+            mouse_down: new.mouse_down && new.mouse_pos.is_some(),
+            mouse_pressed: !last.mouse_down && new.mouse_down,
+            mouse_released: last.mouse_down && !new.mouse_down,
+            mouse_pos: new.mouse_pos,
+            mouse_move,
+            mouse_velocity,
+            scroll_delta: new.scroll_delta,
+            screen_size: new.screen_size,
+            pixels_per_point: new.pixels_per_point,
+            time: new.time,
+            dt,
+            dropped_files: new.dropped_files.clone(),
+            hovered_files: new.hovered_files.clone(),
+            events: new.events.clone(),
+        }
+    }
+}
+
+impl RawInput {
+    pub fn ui(&self, region: &mut crate::Region) {
+        use crate::label;
+        // TODO: simpler way to show values, e.g. `region.value("Mouse Pos:", self.mouse_pos);
+        // TODO: easily change default font!
+        region.add(label!("mouse_down: {}", self.mouse_down));
+        region.add(label!("mouse_pos: {:.1?}", self.mouse_pos));
+        region.add(label!("scroll_delta: {:?}", self.scroll_delta));
+        region.add(label!("screen_size: {:?}", self.screen_size));
+        region.add(label!("pixels_per_point: {}", self.pixels_per_point));
+        region.add(label!("time: {:.3} s", self.time));
+        region.add(label!("events: {:?}", self.events));
+        region.add(label!("dropped_files: {:?}", self.dropped_files));
+        region.add(label!("hovered_files: {:?}", self.hovered_files));
+    }
+}
+
+impl GuiInput {
+    pub fn ui(&self, region: &mut crate::Region) {
+        use crate::label;
+        region.add(label!("mouse_down: {}", self.mouse_down));
+        region.add(label!("mouse_pressed: {}", self.mouse_pressed));
+        region.add(label!("mouse_released: {}", self.mouse_released));
+        region.add(label!("mouse_pos: {:?}", self.mouse_pos));
+        region.add(label!("mouse_move: {:?}", self.mouse_move));
+        region.add(label!(
+            "mouse_velocity: [{:3.0} {:3.0}] points/sec",
+            self.mouse_velocity.x,
+            self.mouse_velocity.y
+        ));
+        region.add(label!("scroll_delta: {:?}", self.scroll_delta));
+        region.add(label!("screen_size: {:?}", self.screen_size));
+        region.add(label!("pixels_per_point: {}", self.pixels_per_point));
+        region.add(label!("time: {}", self.time));
+        region.add(label!("events: {:?}", self.events));
+        region.add(label!("dropped_files: {:?}", self.dropped_files));
+        region.add(label!("hovered_files: {:?}", self.hovered_files));
+    }
+}
diff --git a/emigui/src/lib.rs b/emigui/src/lib.rs
index c3738bd9..1e6288f3 100644
--- a/emigui/src/lib.rs
+++ b/emigui/src/lib.rs
@@ -14,11 +14,13 @@ pub mod example_app;
 mod font;
 mod fonts;
 mod id;
+mod input;
 mod layers;
 mod layout;
 pub mod math;
 mod memory;
 pub mod mesher;
+mod movement_tracker;
 mod region;
 mod style;
 mod texture_atlas;
@@ -31,11 +33,13 @@ pub use {
     context::Context,
     fonts::{FontDefinitions, Fonts, TextStyle},
     id::Id,
+    input::*,
     layers::*,
     layout::{Align, GuiResponse},
     math::*,
     memory::Memory,
     mesher::{Mesh, PaintBatches, Vertex},
+    movement_tracker::MovementTracker,
     region::Region,
     style::Style,
     texture_atlas::Texture,
diff --git a/emigui/src/movement_tracker.rs b/emigui/src/movement_tracker.rs
new file mode 100644
index 00000000..cb450bfa
--- /dev/null
+++ b/emigui/src/movement_tracker.rs
@@ -0,0 +1,120 @@
+use std::collections::VecDeque;
+
+/// This struct tracks recent values of some time series.
+/// This can be used for things like smoothed averages (for e.g. FPS)
+/// or for smoothed velocity (e.g. mouse pointer speed).
+/// All times are in seconds.
+#[derive(Clone, Debug)]
+pub struct MovementTracker<T> {
+    max_len: usize,
+    max_age: f64,
+
+    /// (time, value) pais
+    values: VecDeque<(f64, T)>,
+}
+
+impl<T> MovementTracker<T>
+where
+    T: Copy,
+{
+    pub fn new(max_len: usize, max_age: f64) -> Self {
+        Self {
+            max_len,
+            max_age,
+            values: Default::default(),
+        }
+    }
+
+    pub fn is_empty(&self) -> bool {
+        self.values.is_empty()
+    }
+
+    pub fn len(&self) -> usize {
+        self.values.len()
+    }
+
+    pub fn values<'a>(&'a self) -> impl Iterator<Item = T> + 'a {
+        self.values.iter().map(|(_time, value)| *value)
+    }
+
+    pub fn clear(&mut self) {
+        self.values.clear()
+    }
+
+    /// Values must be added with a monotonically increasing time, or at least not decreasing.
+    pub fn add(&mut self, now: f64, value: T) {
+        if let Some((last_time, _)) = self.values.back() {
+            debug_assert!(now >= *last_time, "Time shouldn't go backwards");
+        }
+        self.values.push_back((now, value));
+        self.flush(now);
+    }
+
+    /// Mean time difference between values in this MovementTracker.
+    pub fn mean_time_interval(&self) -> Option<f32> {
+        if let (Some(first), Some(last)) = (self.values.front(), self.values.back()) {
+            let n = self.len();
+            if n >= 2 {
+                Some((last.0 - first.0) as f32 / ((n - 1) as f32))
+            } else {
+                None
+            }
+        } else {
+            None
+        }
+    }
+
+    fn flush(&mut self, now: f64) {
+        while self.values.len() > self.max_len {
+            self.values.pop_front();
+        }
+        while let Some((front_time, _)) = self.values.front() {
+            if *front_time < now - self.max_age {
+                self.values.pop_front();
+            } else {
+                break;
+            }
+        }
+    }
+}
+
+impl<T> MovementTracker<T>
+where
+    T: Copy,
+    T: std::iter::Sum,
+    T: std::ops::Div<f32, Output = T>,
+{
+    pub fn sum(&self) -> T {
+        self.values().sum()
+    }
+
+    pub fn average(&self) -> Option<T> {
+        let num = self.len();
+        if num > 0 {
+            Some(self.sum() / (num as f32))
+        } else {
+            None
+        }
+    }
+}
+
+impl<T, Vel> MovementTracker<T>
+where
+    T: Copy,
+    T: std::ops::Sub<Output = Vel>,
+    Vel: std::ops::Div<f32, Output = Vel>,
+{
+    /// Calculate a smooth velocity (per second) over the entire time span
+    pub fn velocity(&self) -> Option<Vel> {
+        if let (Some(first), Some(last)) = (self.values.front(), self.values.back()) {
+            let dt = (last.0 - first.0) as f32;
+            if dt > 0.0 {
+                Some((last.1 - first.1) / dt)
+            } else {
+                None
+            }
+        } else {
+            None
+        }
+    }
+}
diff --git a/emigui/src/texture_atlas.rs b/emigui/src/texture_atlas.rs
index 1c46203b..f4f2a2e2 100644
--- a/emigui/src/texture_atlas.rs
+++ b/emigui/src/texture_atlas.rs
@@ -92,10 +92,7 @@ impl TextureAtlas {
 
 impl Texture {
     pub fn ui(&self, region: &mut crate::Region) {
-        use crate::{
-            color::WHITE, label, layout::show_popup, math::*, widgets::Label, Mesh, PaintCmd,
-            Vertex,
-        };
+        use crate::{color::WHITE, label, layout::show_popup, math::*, Mesh, PaintCmd, Vertex};
 
         region.add(label!(
             "Texture size: {} x {} (hover to zoom)",
diff --git a/emigui/src/types.rs b/emigui/src/types.rs
index 0b7994d4..94e88732 100644
--- a/emigui/src/types.rs
+++ b/emigui/src/types.rs
@@ -1,151 +1,12 @@
 use crate::{
     color::Color,
     fonts::TextStyle,
-    math::{Pos2, Rect, Vec2},
+    math::{Pos2, Rect},
     mesher::{Mesh, Path},
 };
 
 // ----------------------------------------------------------------------------
 
-/// What the integration gives to the gui.
-/// All coordinates in emigui is in point/logical coordinates.
-#[derive(Clone, Debug, Default, Deserialize)]
-#[serde(default)]
-pub struct RawInput {
-    /// Is the button currently down?
-    pub mouse_down: bool,
-
-    /// Current position of the mouse in points.
-    pub mouse_pos: Option<Pos2>,
-
-    /// How many pixels the user scrolled
-    pub scroll_delta: Vec2,
-
-    /// Size of the screen in points.
-    pub screen_size: Vec2,
-
-    /// Also known as device pixel ratio, > 1 for HDPI screens.
-    pub pixels_per_point: f32,
-
-    /// Time in seconds. Relative to whatever. Used for animation.
-    pub time: f64,
-
-    /// Files has been dropped into the window.
-    pub dropped_files: Vec<std::path::PathBuf>,
-
-    /// Someone is threatening to drop these on us.
-    pub hovered_files: Vec<std::path::PathBuf>,
-
-    /// In-order events received this frame
-    pub events: Vec<Event>,
-}
-
-/// What emigui maintains
-#[derive(Clone, Debug, Default)]
-pub struct GuiInput {
-    // TODO: mouse: Mouse as separate
-    //
-    /// Is the button currently down?
-    /// true the frame when it is pressed,
-    /// false the frame it is released.
-    pub mouse_down: bool,
-
-    /// The mouse went from !down to down
-    pub mouse_pressed: bool,
-
-    /// The mouse went from down to !down
-    pub mouse_released: bool,
-
-    /// Current position of the mouse in points.
-    /// None for touch screens when finger is not down.
-    pub mouse_pos: Option<Pos2>,
-
-    /// How much the mouse moved compared to last frame, in points.
-    pub mouse_move: Vec2,
-
-    /// How many pixels the user scrolled
-    pub scroll_delta: Vec2,
-
-    /// Size of the screen in points.
-    pub screen_size: Vec2,
-
-    /// Also known as device pixel ratio, > 1 for HDPI screens.
-    pub pixels_per_point: f32,
-
-    /// Time in seconds. Relative to whatever. Used for animation.
-    pub time: f64,
-
-    /// Files has been dropped into the window.
-    pub dropped_files: Vec<std::path::PathBuf>,
-
-    /// Someone is threatening to drop these on us.
-    pub hovered_files: Vec<std::path::PathBuf>,
-
-    /// In-order events received this frame
-    pub events: Vec<Event>,
-}
-
-#[derive(Clone, Debug, Eq, Ord, PartialEq, PartialOrd, Deserialize)]
-#[serde(rename_all = "snake_case")]
-pub enum Event {
-    Copy,
-    Cut,
-    /// Text input, e.g. via keyboard or paste action
-    Text(String),
-    Key {
-        key: Key,
-        pressed: bool,
-    },
-}
-
-#[derive(Clone, Debug, Eq, Ord, PartialEq, PartialOrd, Deserialize)]
-#[serde(rename_all = "snake_case")]
-pub enum Key {
-    Alt,
-    Backspace,
-    Control,
-    Delete,
-    Down,
-    End,
-    Escape,
-    Home,
-    Insert,
-    Left,
-    /// Windows key or Mac Command key
-    Logo,
-    PageDown,
-    PageUp,
-    Return,
-    Right,
-    Shift,
-    // Space,
-    Tab,
-    Up,
-}
-
-impl GuiInput {
-    pub fn from_last_and_new(last: &RawInput, new: &RawInput) -> GuiInput {
-        let mouse_move = new
-            .mouse_pos
-            .and_then(|new| last.mouse_pos.map(|last| new - last))
-            .unwrap_or_default();
-        GuiInput {
-            mouse_down: new.mouse_down && new.mouse_pos.is_some(),
-            mouse_pressed: !last.mouse_down && new.mouse_down,
-            mouse_released: last.mouse_down && !new.mouse_down,
-            mouse_pos: new.mouse_pos,
-            mouse_move,
-            scroll_delta: new.scroll_delta,
-            screen_size: new.screen_size,
-            pixels_per_point: new.pixels_per_point,
-            time: new.time,
-            dropped_files: new.dropped_files.clone(),
-            hovered_files: new.hovered_files.clone(),
-            events: new.events.clone(),
-        }
-    }
-}
-
 #[derive(Clone, Default, Serialize)]
 pub struct Output {
     pub cursor_icon: CursorIcon,
diff --git a/emigui/src/widgets.rs b/emigui/src/widgets.rs
index db103d50..5804b367 100644
--- a/emigui/src/widgets.rs
+++ b/emigui/src/widgets.rs
@@ -55,8 +55,8 @@ impl Label {
 /// Usage:  label!("Foo: {}", bar)
 #[macro_export]
 macro_rules! label {
-    ($fmt:expr) => (Label::new($fmt));
-    ($fmt:expr, $($arg:tt)*) => (Label::new(format!($fmt, $($arg)*)));
+    ($fmt:expr) => ($crate::widgets::Label::new($fmt));
+    ($fmt:expr, $($arg:tt)*) => ($crate::widgets::Label::new(format!($fmt, $($arg)*)));
 }
 
 impl Widget for Label {
diff --git a/example_glium/src/main.rs b/example_glium/src/main.rs
index 9b59d03d..09459d35 100644
--- a/example_glium/src/main.rs
+++ b/example_glium/src/main.rs
@@ -1,9 +1,6 @@
 #![deny(warnings)]
 #[allow(clippy::single_match)]
-use std::{
-    collections::VecDeque,
-    time::{Duration, Instant},
-};
+use std::time::{Duration, Instant};
 
 use {
     emigui::{containers::*, example_app::ExampleWindow, widgets::*, *},
@@ -42,7 +39,7 @@ fn main() {
     let start_time = Instant::now();
     let mut running = true;
     let mut frame_start = Instant::now();
-    let mut frame_times = VecDeque::new();
+    let mut frame_times = emigui::MovementTracker::new(1000, 1.0);
     let mut example_app = ExampleWindow::default();
     let mut clipboard = emigui_glium::init_clipboard();
 
@@ -82,8 +79,15 @@ fn main() {
 
         region.add(
             label!(
-                "Frame time: {:.1} ms (excludes painting)",
-                1e3 * mean_frame_time(&frame_times)
+                "CPU usage: {:.2} ms (excludes painting)",
+                1e3 * frame_times.average().unwrap_or_default()
+            )
+            .text_style(TextStyle::Monospace),
+        );
+        region.add(
+            label!(
+                "FPS: {:.1}",
+                1.0 / frame_times.mean_time_interval().unwrap_or_default()
             )
             .text_style(TextStyle::Monospace),
         );
@@ -108,10 +112,10 @@ fn main() {
 
         let (output, paint_batches) = emigui.end_frame();
 
-        frame_times.push_back((Instant::now() - emigui_start).as_secs_f64());
-        while frame_times.len() > 30 {
-            frame_times.pop_front();
-        }
+        frame_times.add(
+            raw_input.time,
+            (Instant::now() - emigui_start).as_secs_f64() as f32,
+        );
 
         painter.paint_batches(&display, paint_batches, emigui.texture());
         emigui_glium::handle_output(output, &display, clipboard.as_mut());
@@ -121,11 +125,3 @@ fn main() {
         eprintln!("ERROR: Failed to save emigui state: {}", err);
     }
 }
-
-pub fn mean_frame_time(frame_times: &VecDeque<f64>) -> f64 {
-    if frame_times.is_empty() {
-        0.0
-    } else {
-        frame_times.iter().sum::<f64>() / (frame_times.len() as f64)
-    }
-}
diff --git a/example_wasm/src/lib.rs b/example_wasm/src/lib.rs
index 31f96023..d1eedee1 100644
--- a/example_wasm/src/lib.rs
+++ b/example_wasm/src/lib.rs
@@ -26,7 +26,7 @@ pub struct State {
     emigui: Emigui,
     webgl_painter: emigui_wasm::webgl::Painter,
 
-    frame_times: std::collections::VecDeque<f64>,
+    frame_times: emigui::MovementTracker<f32>,
 }
 
 impl State {
@@ -37,7 +37,7 @@ impl State {
             example_app: Default::default(),
             emigui,
             webgl_painter: emigui_wasm::webgl::Painter::new(canvas_id)?,
-            frame_times: Default::default(),
+            frame_times: emigui::MovementTracker::new(1000, 1.0),
         })
     }
 
@@ -69,15 +69,17 @@ impl State {
             region.add_label(self.webgl_painter.debug_info());
         });
 
-        let mean_frame_time = if self.frame_times.is_empty() {
-            0.0
-        } else {
-            self.frame_times.iter().sum::<f64>() / (self.frame_times.len() as f64)
-        };
         region.add(
             label!(
-                "Frame time: {:.1} ms (excludes painting)",
-                1e3 * mean_frame_time
+                "CPU usage: {:.2} ms (excludes painting)",
+                1e3 * self.frame_times.average().unwrap_or_default()
+            )
+            .text_style(TextStyle::Monospace),
+        );
+        region.add(
+            label!(
+                "FPS: {:.1}",
+                1.0 / self.frame_times.mean_time_interval().unwrap_or_default()
             )
             .text_style(TextStyle::Monospace),
         );
@@ -101,10 +103,8 @@ impl State {
         let bg_color = srgba(0, 0, 0, 0); // Use background css color.
         let (output, batches) = self.emigui.end_frame();
 
-        self.frame_times.push_back(now_sec() - everything_start);
-        while self.frame_times.len() > 30 {
-            self.frame_times.pop_front();
-        }
+        let now = now_sec();
+        self.frame_times.add(now, (now - everything_start) as f32);
 
         self.webgl_painter.paint_batches(
             bg_color,