Fix flicker in egui virtual list when in a egui_router animation (#92)

Author: lucasmerlin

crates/egui_router/src/transition.rs

@@ -94,6 +94,8 @@ impl TransitionTrait for SlideTransition {
     fn create_child_ui(&self, ui: &mut Ui, t: f32, with_id: Id) -> Ui {
         let available_size = ui.available_size();
         let offset = available_size * (1.0 - t) * self.amount;
+        // Round to pixels to prevent sub-pixel jitter and flickering in child components
+        let offset = Vec2::new(offset.x.round(), offset.y.round());
         let child_rect = ui.max_rect().translate(offset);
 
         ui.new_child(UiBuilder::new().max_rect(child_rect).id_salt(with_id))

crates/egui_virtual_list/src/lib.rs

@@ -130,9 +130,9 @@ impl VirtualList {
     ) -> VirtualListResponse {
         let mut scroll_to_item_index_visibility = None;
         {
-            let available_width_rounded = (ui.available_width() * 10.0).round() / 10.0;
+            let available_width_rounded = (ui.max_rect().width() * 10.0).round() / 10.0;
             if let Some(last_width) = self.last_width {
-                if available_width_rounded != last_width {
+                if (available_width_rounded - last_width).abs() > 1.0 {
                     self.last_width = Some(available_width_rounded);
                     if self.check_for_resize {
                         self.last_known_row_index = None;