From 019412543c604602c7b1aeadbdae4ba66413e789 Mon Sep 17 00:00:00 2001
From: Jonathan Johnson <jon@khonsulabs.com>
Date: Sat, 11 Nov 2023 13:47:35 -0800
Subject: [PATCH] Lerp for ThemeMode

---
 examples/theme.rs | 13 +++----------
 src/window.rs     | 31 +++++++++++++++++++++++++++++--
 2 files changed, 32 insertions(+), 12 deletions(-)

diff --git a/examples/theme.rs b/examples/theme.rs
index ee605c9..e315a06 100644
--- a/examples/theme.rs
+++ b/examples/theme.rs
@@ -72,18 +72,11 @@ fn main() -> gooey::Result {
 }
 
 fn dark_mode_slider() -> (Dynamic<ThemeMode>, impl MakeWidget) {
-    let on_off = Dynamic::new(true);
-    let theme_mode = on_off.map_each(|dark| {
-        if *dark {
-            ThemeMode::Dark
-        } else {
-            ThemeMode::Light
-        }
-    });
+    let theme_mode = Dynamic::default();
 
     (
-        theme_mode,
-        Stack::rows(Label::new("Theme Mode").and(Slider::<bool>::from_value(on_off))),
+        theme_mode.clone(),
+        Stack::rows(Label::new("Theme Mode").and(Slider::<ThemeMode>::from_value(theme_mode))),
     )
 }
 
diff --git a/src/window.rs b/src/window.rs
index 615a56f..79e8a63 100644
--- a/src/window.rs
+++ b/src/window.rs
@@ -18,12 +18,13 @@ use kludgine::app::winit::keyboard::Key;
 use kludgine::app::winit::window;
 use kludgine::app::WindowBehavior as _;
 use kludgine::figures::units::{Px, UPx};
-use kludgine::figures::{IntoSigned, IntoUnsigned, Point, Rect, ScreenScale, Size};
+use kludgine::figures::{IntoSigned, IntoUnsigned, Point, Ranged, Rect, ScreenScale, Size};
 use kludgine::render::Drawing;
 use kludgine::wgpu::CompositeAlphaMode;
 use kludgine::Kludgine;
 use tracing::Level;
 
+use crate::animation::{LinearInterpolate, PercentBetween, ZeroToOne};
 use crate::context::{
     AsEventContext, EventContext, Exclusive, GraphicsContext, LayoutContext, RedrawStatus,
     WidgetContext,
@@ -1057,11 +1058,12 @@ pub(crate) mod sealed {
 }
 
 /// Controls whether the light or dark theme is applied.
-#[derive(Clone, Copy, Debug, Eq, PartialEq, Ord, PartialOrd)]
+#[derive(Default, Clone, Copy, Debug, Eq, PartialEq, Ord, PartialOrd)]
 pub enum ThemeMode {
     /// Applies the light theme
     Light,
     /// Applies the dark theme
+    #[default]
     Dark,
 }
 
@@ -1082,3 +1084,28 @@ impl From<ThemeMode> for window::Theme {
         }
     }
 }
+
+impl LinearInterpolate for ThemeMode {
+    fn lerp(&self, target: &Self, percent: f32) -> Self {
+        if percent >= 0.5 {
+            *target
+        } else {
+            *self
+        }
+    }
+}
+
+impl PercentBetween for ThemeMode {
+    fn percent_between(&self, min: &Self, max: &Self) -> ZeroToOne {
+        if *min == *max || *self == *min {
+            ZeroToOne::ZERO
+        } else {
+            ZeroToOne::ONE
+        }
+    }
+}
+
+impl Ranged for ThemeMode {
+    const MAX: Self = Self::Dark;
+    const MIN: Self = Self::Light;
+}