Add UiScale interpolator for UiTransform

CHANGELOG.md

@@ -3,6 +3,7 @@
 ## Unreleased - XXXX-XX-XX
 
 - Make AnimationTarget derives Clone and Copy by [#90](https://github.com/Multirious/bevy_tween/pull/90)
+- Add UiScale interpolator for UiTransform by [#92](https://github.com/Multirious/bevy_tween/pull/92)
 
 ## v0.13.0 - 2026-07-03
 
@@ -36,6 +37,7 @@
   - Add `time_context_animation` example.
 
 Internal:
+
 - Update flake by [#77](https://github.com/Multirious/bevy_tween/pull/77)
   - Use latest instead of a version for stableRust in flake.nix
   - `nix flake update`

src/interpolate.rs

@@ -75,6 +75,8 @@ mod sprite;
 mod transform;
 #[cfg(feature = "bevy_ui")]
 mod ui;
+#[cfg(feature = "bevy_ui")]
+mod ui_transform;
 
 use std::marker::PhantomData;
 
@@ -86,6 +88,9 @@ pub use sprite::*;
 #[cfg(feature = "bevy_ui")]
 pub use ui::*;
 
+#[cfg(feature = "bevy_ui")]
+pub use ui_transform::*;
+
 use crate::{BevyTweenRegisterSystems, tween};
 use bevy::ecs::schedule::{InternedScheduleLabel, ScheduleLabel};
 

src/interpolate/ui_transform.rs

@@ -0,0 +1,76 @@
+use crate::interpolate::Interpolator;
+use bevy::prelude::*;
+
+/// [`Interpolator`] for [`UiTransform`]'s scale
+#[derive(Debug, Default, Clone, PartialEq, Reflect)]
+pub struct UiScale {
+    /// Starting [`UiTransform`]'s scale
+    pub start: Vec2,
+    /// Ending [`UiTransform`]'s scale
+    pub end: Vec2,
+    /// whether it increments by delta or sets absolute values
+    pub delta: bool,
+}
+impl Interpolator for UiScale {
+    type Item = UiTransform;
+
+    fn interpolate(
+        &self,
+        item: &mut Self::Item,
+        value: f32,
+        previous_value: f32,
+    ) {
+        if self.delta {
+            let previous_scale = self.start.lerp(self.end, previous_value);
+            let next_scale = self.start.lerp(self.end, value);
+            let scale_delta = next_scale - previous_scale;
+            item.scale += scale_delta;
+        } else {
+            item.scale = self.start.lerp(self.end, value);
+        }
+    }
+}
+
+/// Constructor for [`UiScale`]
+pub fn ui_scale(start: Vec2, end: Vec2) -> UiScale {
+    UiScale {
+        start,
+        end,
+        delta: false,
+    }
+}
+
+/// Constructor for [`UiScale`] relative to previous value using currying.
+pub fn ui_scale_to(to: Vec2) -> impl Fn(&mut Vec2) -> UiScale {
+    move |state| {
+        let start = *state;
+        let end = to;
+        *state = to;
+        ui_scale(start, end)
+    }
+}
+
+/// Constructor for [`UiScale`] relative to previous value using currying.
+pub fn ui_scale_by(by: Vec2) -> impl Fn(&mut Vec2) -> UiScale {
+    move |state| {
+        let start = *state;
+        let end = *state + by;
+        *state += by;
+        ui_scale(start, end)
+    }
+}
+
+/// Constructor for [`UiScale`] relative to previous value.
+/// Since this is a delta tween, it can run alongside other ongoing tweens of that type.
+pub fn ui_scale_delta_by(by: Vec2) -> impl Fn(&mut Vec2) -> UiScale {
+    move |state| {
+        let start = *state;
+        let end = *state + by;
+        *state += by;
+        UiScale {
+            start,
+            end,
+            delta: true,
+        }
+    }
+}