From f9df09b53d2b1eac23cc0ace8e9f84fe067f41e9 Mon Sep 17 00:00:00 2001
From: Varphone Wong <varphone@qq.com>
Date: Fri, 7 Jun 2024 09:27:32 +0800
Subject: [PATCH] `emath`: Add `quadratic_in_inverse`

---
 crates/emath/src/easing.rs | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/crates/emath/src/easing.rs b/crates/emath/src/easing.rs
index 352c451c2..e8d566741 100644
--- a/crates/emath/src/easing.rs
+++ b/crates/emath/src/easing.rs
@@ -26,6 +26,14 @@ pub fn quadratic_in(t: f32) -> f32 {
     t * t
 }
 
+/// Inverse of `quadratic_in`.
+///
+/// This is not the same as `1.0 - quadratic_in(t)`.
+#[inline]
+pub fn quadratic_in_inverse(y: f32) -> f32 {
+    y.sqrt()
+}
+
 /// <https://easings.net/#easeOutQuad>
 ///
 /// Same as `1.0 - quadratic_in(1.0 - t)`.