From 45fe192f75946f98a6e1d6e418f17d055633e1cd Mon Sep 17 00:00:00 2001
From: kernelkind <kernelkind@gmail.com>
Date: Tue, 15 Apr 2025 18:37:38 -0400
Subject: [PATCH] introduce `ImagePulseTint`

Signed-off-by: kernelkind <kernelkind@gmail.com>
---
 crates/notedeck_ui/src/anim.rs | 71 ++++++++++++++++++++++++++++++++++
 crates/notedeck_ui/src/lib.rs  |  2 +-
 2 files changed, 72 insertions(+), 1 deletion(-)

diff --git a/crates/notedeck_ui/src/anim.rs b/crates/notedeck_ui/src/anim.rs
index 94007d9e..203a7411 100644
--- a/crates/notedeck_ui/src/anim.rs
+++ b/crates/notedeck_ui/src/anim.rs
@@ -138,3 +138,74 @@ impl AnimationHelper {
         min_object_size + ((max_object_size - min_object_size) * self.animation_progress)
     }
 }
+
+pub struct ImagePulseTint<'a> {
+    ctx: &'a egui::Context,
+    id: egui::Id,
+    image: egui::Image<'a>,
+    color_unmultiplied: &'a [u8; 3],
+    alpha_min: u8,
+    alpha_max: u8,
+    animation_speed: f32,
+}
+
+impl<'a> ImagePulseTint<'a> {
+    pub fn new(
+        ctx: &'a egui::Context,
+        id: egui::Id,
+        image: egui::Image<'a>,
+        color_unmultiplied: &'a [u8; 3],
+        alpha_min: u8,
+        alpha_max: u8,
+    ) -> Self {
+        Self {
+            ctx,
+            id,
+            image,
+            color_unmultiplied,
+            alpha_min,
+            alpha_max,
+            animation_speed: ANIM_SPEED,
+        }
+    }
+
+    pub fn with_speed(mut self, speed: f32) -> Self {
+        self.animation_speed = speed;
+        self
+    }
+
+    pub fn animate(self) -> egui::Image<'a> {
+        let pulse_direction = if let Some(pulse_dir) = self.ctx.data(|d| d.get_temp(self.id)) {
+            pulse_dir
+        } else {
+            self.ctx.data_mut(|d| d.insert_temp(self.id, false));
+            false
+        };
+
+        let alpha_min_f32 = self.alpha_min as f32;
+        let target = if pulse_direction {
+            self.alpha_max as f32 - alpha_min_f32
+        } else {
+            0.0
+        };
+
+        let cur_val = self
+            .ctx
+            .animate_value_with_time(self.id, target, self.animation_speed);
+
+        if (target - cur_val).abs() < 0.5 {
+            self.ctx
+                .data_mut(|d| d.insert_temp(self.id, !pulse_direction));
+        }
+
+        let alpha =
+            (cur_val + alpha_min_f32).clamp(self.alpha_min as f32, self.alpha_max as f32) as u8;
+
+        self.image.tint(egui::Color32::from_rgba_unmultiplied(
+            self.color_unmultiplied[0],
+            self.color_unmultiplied[1],
+            self.color_unmultiplied[2],
+            alpha,
+        ))
+    }
+}
diff --git a/crates/notedeck_ui/src/lib.rs b/crates/notedeck_ui/src/lib.rs
index 3747426c..69600975 100644
--- a/crates/notedeck_ui/src/lib.rs
+++ b/crates/notedeck_ui/src/lib.rs
@@ -6,5 +6,5 @@ pub mod icons;
 pub mod images;
 pub mod profile;
 
-pub use anim::AnimationHelper;
+pub use anim::{AnimationHelper, ImagePulseTint};
 pub use profile::ProfilePic;