T00 foundation: theme, motion, assets, icon, buttons, gallery

Theme tokens in light and dark with high contrast, a palette cross-fade,
motion curves and a damped spring, embedded Lucide icons with Inter and
JetBrains Mono, Icon, Button, IconButton, and a gallery that captures
its own window. Reviewed by codex gpt-6-astra (max): PASS in round 3.

src/motion/curve.rs

@@ -0,0 +1,78 @@
+use std::time::Duration;
+
+use gpui::App;
+
+use crate::theme::ActiveTheme;
+
+pub const FAST: Duration = Duration::from_millis(120);
+pub const BASE: Duration = Duration::from_millis(200);
+pub const SLOW: Duration = Duration::from_millis(320);
+pub const THEME: Duration = Duration::from_millis(280);
+
+const DAMPING: f32 = 0.75;
+const OMEGA: f32 = 6.91 / DAMPING;
+
+/// `base`, or one millisecond under reduced motion.
+pub fn duration(base: Duration, cx: &App) -> Duration {
+    if cx.theme().reduced_motion {
+        Duration::from_millis(1)
+    } else {
+        base
+    }
+}
+
+pub fn lerp(from: f32, to: f32, t: f32) -> f32 {
+    from + (to - from) * t
+}
+
+pub fn ease_out_cubic(t: f32) -> f32 {
+    1.0 - (1.0 - t).powi(3)
+}
+
+pub fn ease_in_out_cubic(t: f32) -> f32 {
+    if t < 0.5 {
+        4.0 * t * t * t
+    } else {
+        1.0 - (-2.0 * t + 2.0).powi(3) / 2.0
+    }
+}
+
+/// Damped spring. Overshoots; not a gpui easing.
+pub fn spring(t: f32) -> f32 {
+    if t >= 1.0 {
+        return 1.0;
+    }
+    let damped = OMEGA * (1.0 - DAMPING * DAMPING).sqrt();
+    let decay = (-DAMPING * OMEGA * t).exp();
+    1.0 - decay * ((damped * t).cos() + DAMPING * OMEGA / damped * (damped * t).sin())
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn easings_pin_their_ends() {
+        for ease in [ease_out_cubic, ease_in_out_cubic, spring] {
+            assert!(ease(0.0).abs() < 1e-6);
+            assert_eq!(ease(1.0), 1.0);
+        }
+    }
+
+    #[test]
+    fn spring_overshoots_a_little_then_settles() {
+        let peak = (0..=100)
+            .map(|i| spring(i as f32 / 100.0))
+            .fold(0.0, f32::max);
+        assert!(peak > 1.01 && peak < 1.05, "peak {peak}");
+        assert!((spring(0.95) - 1.0).abs() < 0.01);
+    }
+
+    #[test]
+    fn ease_in_out_is_symmetric() {
+        for i in 0..=10 {
+            let t = i as f32 / 10.0;
+            assert!((ease_in_out_cubic(t) + ease_in_out_cubic(1.0 - t) - 1.0).abs() < 1e-5);
+        }
+    }
+}

src/motion/mod.rs

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+mod curve;
+
+pub use curve::*;