From bfb1c0c7d3390bd351edc76ab6c4967a797e958e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?H=C3=A9ctor=20Ram=C3=B3n=20Jim=C3=A9nez?=
 <hector0193@gmail.com>
Date: Mon, 30 Jan 2023 05:01:28 +0100
Subject: [PATCH] Fix layout translation in `overlay::Group`

This bug produced improper positioning of overlays of elements inside a
`Scrollable`.
---
 core/src/vector.rs            |  5 +++++
 native/src/overlay/element.rs | 10 ++++++++--
 native/src/overlay/group.rs   |  6 ++++--
 native/src/user_interface.rs  | 18 ++++++++++--------
 4 files changed, 27 insertions(+), 12 deletions(-)

diff --git a/core/src/vector.rs b/core/src/vector.rs
index b550869c7f..1380c3b370 100644
--- a/core/src/vector.rs
+++ b/core/src/vector.rs
@@ -15,6 +15,11 @@ impl<T> Vector<T> {
     }
 }
 
+impl Vector {
+    /// The zero [`Vector`].
+    pub const ZERO: Self = Self::new(0.0, 0.0);
+}
+
 impl<T> std::ops::Add for Vector<T>
 where
     T: std::ops::Add<Output = T>,
diff --git a/native/src/overlay/element.rs b/native/src/overlay/element.rs
index bdf7766e7f..237d25d175 100644
--- a/native/src/overlay/element.rs
+++ b/native/src/overlay/element.rs
@@ -53,8 +53,14 @@ where
     }
 
     /// Computes the layout of the [`Element`] in the given bounds.
-    pub fn layout(&self, renderer: &Renderer, bounds: Size) -> layout::Node {
-        self.overlay.layout(renderer, bounds, self.position)
+    pub fn layout(
+        &self,
+        renderer: &Renderer,
+        bounds: Size,
+        translation: Vector,
+    ) -> layout::Node {
+        self.overlay
+            .layout(renderer, bounds, self.position + translation)
     }
 
     /// Processes a runtime [`Event`].
diff --git a/native/src/overlay/group.rs b/native/src/overlay/group.rs
index 5c9cf809b3..1126f0cf11 100644
--- a/native/src/overlay/group.rs
+++ b/native/src/overlay/group.rs
@@ -66,13 +66,15 @@ where
         &self,
         renderer: &Renderer,
         bounds: Size,
-        _position: Point,
+        position: Point,
     ) -> layout::Node {
+        let translation = position - Point::ORIGIN;
+
         layout::Node::with_children(
             bounds,
             self.children
                 .iter()
-                .map(|child| child.layout(renderer, bounds))
+                .map(|child| child.layout(renderer, bounds, translation))
                 .collect(),
         )
     }
diff --git a/native/src/user_interface.rs b/native/src/user_interface.rs
index 0def730cdd..80dece2155 100644
--- a/native/src/user_interface.rs
+++ b/native/src/user_interface.rs
@@ -6,7 +6,9 @@ use crate::mouse;
 use crate::renderer;
 use crate::widget;
 use crate::window;
-use crate::{Clipboard, Element, Layout, Point, Rectangle, Shell, Size};
+use crate::{
+    Clipboard, Element, Layout, Point, Rectangle, Shell, Size, Vector,
+};
 
 /// A set of interactive graphical elements with a specific [`Layout`].
 ///
@@ -203,7 +205,7 @@ where
             let bounds = self.bounds;
 
             let mut overlay = manual_overlay.as_mut().unwrap();
-            let mut layout = overlay.layout(renderer, bounds);
+            let mut layout = overlay.layout(renderer, bounds, Vector::ZERO);
             let mut event_statuses = Vec::new();
 
             for event in events.iter().cloned() {
@@ -252,7 +254,7 @@ where
                     overlay = manual_overlay.as_mut().unwrap();
 
                     shell.revalidate_layout(|| {
-                        layout = overlay.layout(renderer, bounds);
+                        layout = overlay.layout(renderer, bounds, Vector::ZERO);
                     });
                 }
 
@@ -434,10 +436,9 @@ where
             .as_widget_mut()
             .overlay(&mut self.state, Layout::new(&self.base), renderer)
         {
-            let overlay_layout = self
-                .overlay
-                .take()
-                .unwrap_or_else(|| overlay.layout(renderer, self.bounds));
+            let overlay_layout = self.overlay.take().unwrap_or_else(|| {
+                overlay.layout(renderer, self.bounds, Vector::ZERO)
+            });
 
             let new_cursor_position =
                 if overlay_layout.bounds().contains(cursor_position) {
@@ -538,7 +539,8 @@ where
             renderer,
         ) {
             if self.overlay.is_none() {
-                self.overlay = Some(overlay.layout(renderer, self.bounds));
+                self.overlay =
+                    Some(overlay.layout(renderer, self.bounds, Vector::ZERO));
             }
 
             overlay.operate(