Keep focused item in view when resizing, part of #109

src/mouse_area.rs

@@ -36,6 +36,7 @@ pub struct MouseArea<'a, Message> {
     on_press: Option<Box<dyn Fn(Option<Point>) -> Message + 'a>>,
     on_drag_end: Option<Box<dyn Fn(Option<Point>) -> Message + 'a>>,
     on_release: Option<Box<dyn Fn(Option<Point>) -> Message + 'a>>,
+    on_resize: Option<Box<dyn Fn(Size) -> Message + 'a>>,
     on_right_press: Option<Box<dyn Fn(Option<Point>) -> Message + 'a>>,
     on_right_press_no_capture: Option<Box<dyn Fn(Option<Point>) -> Message + 'a>>,
     on_right_release: Option<Box<dyn Fn(Option<Point>) -> Message + 'a>>,
@@ -85,6 +86,13 @@ impl<'a, Message> MouseArea<'a, Message> {
         self
     }
 
+    /// The message to emit on resizing.
+    #[must_use]
+    pub fn on_resize(mut self, message: impl Fn(Size) -> Message + 'a) -> Self {
+        self.on_resize = Some(Box::new(message));
+        self
+    }
+
     /// The message to emit on a right button press.
     #[must_use]
     pub fn on_right_press(mut self, message: impl Fn(Option<Point>) -> Message + 'a) -> Self {
@@ -182,6 +190,7 @@ struct State {
     drag_initiated: Option<Point>,
     modifiers: Modifiers,
     prev_click: Option<(mouse::Click, Instant)>,
+    size: Option<Size>,
 }
 
 impl State {
@@ -235,6 +244,7 @@ impl<'a, Message> MouseArea<'a, Message> {
             on_double_click: None,
             on_press: None,
             on_release: None,
+            on_resize: None,
             on_right_press: None,
             on_right_press_no_capture: None,
             on_right_release: None,
@@ -449,6 +459,14 @@ fn update<Message: Clone>(
 ) -> event::Status {
     let layout_bounds = layout.bounds();
 
+    if let Some(message) = widget.on_resize.as_ref() {
+        let size = layout_bounds.size();
+        if state.size != Some(size) {
+            state.size = Some(size);
+            shell.publish(message(size));
+        }
+    }
+
     if state.drag_initiated.is_none() && !cursor.is_over(layout_bounds) {
         return event::Status::Ignored;
     }

src/tab.rs

@@ -849,6 +849,7 @@ pub enum Message {
     RightClick(Option<usize>),
     MiddleClick(usize),
     Scroll(Viewport),
+    ScrollToFocus,
     SelectAll,
     SetSort(HeadingOptions, bool),
     Thumbnail(PathBuf, ItemThumbnail),
@@ -2096,6 +2097,14 @@ impl Tab {
             Message::Scroll(viewport) => {
                 self.scroll_opt = Some(viewport.absolute_offset());
             }
+            Message::ScrollToFocus => {
+                if let Some(offset) = self.select_focus_scroll() {
+                    commands.push(Command::Iced(scrollable::scroll_to(
+                        self.scrollable_id.clone(),
+                        offset,
+                    )));
+                }
+            }
             Message::SelectAll => {
                 self.select_all();
                 if self.select_focus.take().is_some() {
@@ -3464,6 +3473,8 @@ impl Tab {
         let mut mouse_area = mouse_area::MouseArea::new(item_view)
             .on_press(move |_point_opt| Message::Click(None))
             .on_release(|_| Message::ClickRelease(None))
+            //TODO: better way to keep focused item in view
+            .on_resize(|_| Message::ScrollToFocus)
             .on_back_press(move |_point_opt| Message::GoPrevious)
             .on_forward_press(move |_point_opt| Message::GoNext)
             .on_scroll(respond_to_scroll_direction);