Adding in new functionality to scroll the file window when dragging outside the viewport of the scrollable

src/app.rs

@@ -54,6 +54,7 @@ use std::{
     sync::{Arc, Mutex},
     time::{self, Instant},
 };
+use cosmic::iced::mouse::Event::CursorMoved;
 use tokio::sync::mpsc;
 use trash::TrashItem;
 #[cfg(feature = "wayland")]
@@ -277,6 +278,7 @@ pub enum Message {
     Config(Config),
     Copy(Option<Entity>),
     CosmicSettings(&'static str),
+    CursorMoved(Point),
     Cut(Option<Entity>),
     DesktopConfig(DesktopConfig),
     DesktopViewOptions,
@@ -1926,6 +1928,10 @@ impl Application for App {
                 let contents = ClipboardCopy::new(ClipboardKind::Copy, &paths);
                 return clipboard::write_data(contents);
             }
+            Message::CursorMoved(pos) => {
+                let entity = self.tab_model.active();
+                return self.update(Message::TabMessage(Some(entity), tab::Message::CursorMoved(pos)));
+            }
             Message::Cut(entity_opt) => {
                 let paths = self.selected_paths(entity_opt);
                 let contents = ClipboardCopy::new(ClipboardKind::Cut, &paths);
@@ -4536,7 +4542,8 @@ impl Application for App {
                         }
                         _ => None,
                     }
-                }
+                },
+                Event::Mouse(CursorMoved { position: pos }) => Some(Message::CursorMoved(pos)),
                 _ => None,
             }),
             Config::subscription().map(|update| {

src/mouse_area.rs

@@ -199,8 +199,8 @@ impl<'a, Message, F> OnMouseButton<'a, Message> for F where F: Fn(Option<Point>)
 pub trait OnDrag<'a, Message>: Fn(Option<Rectangle>) -> Message + 'a {}
 impl<'a, Message, F> OnDrag<'a, Message> for F where F: Fn(Option<Rectangle>) -> Message + 'a {}
 
-pub trait OnResize<'a, Message>: Fn(Size) -> Message + 'a {}
+pub trait OnResize<'a, Message>: Fn(Size, Rectangle) -> Message + 'a {}
-impl<'a, Message, F> OnResize<'a, Message> for F where F: Fn(Size) -> Message + 'a {}
+impl<'a, Message, F> OnResize<'a, Message> for F where F: Fn(Size, Rectangle) -> Message + 'a {}
 
 pub trait OnScroll<'a, Message>: Fn(mouse::ScrollDelta, Modifiers) -> Option<Message> + 'a {}
 impl<'a, Message, F> OnScroll<'a, Message> for F where
@@ -374,6 +374,7 @@ where
             cursor,
             shell,
             tree.state.downcast_mut::<State>(),
+            viewport,
         )
     }
 
@@ -493,6 +494,7 @@ fn update<Message: Clone>(
     cursor: mouse::Cursor,
     shell: &mut Shell<'_, Message>,
     state: &mut State,
+    viewport: &Rectangle
 ) -> event::Status {
     let layout_bounds = layout.bounds();
 
@@ -500,7 +502,7 @@ fn update<Message: Clone>(
         let size = layout_bounds.size();
         if state.size != Some(size) {
             state.size = Some(size);
-            shell.publish(message(size));
+            shell.publish(message(size, *viewport));
         }
     }
 

src/tab.rs

@@ -83,6 +83,8 @@ const MAX_SEARCH_RESULTS: usize = 200;
 //TODO: configurable thumbnail size?
 const THUMBNAIL_SIZE: u32 = (ICON_SIZE_GRID as u32) * (ICON_SCALE_MAX as u32);
 
+const DRAG_SCROLL_DISTANCE: u8 = 5;
+
 //TODO: adjust for locales?
 const DATE_TIME_FORMAT: &str = "%b %-d, %-Y, %-I:%M %p";
 const TIME_FORMAT: &str = "%-I:%M %p";
@@ -1121,6 +1123,8 @@ pub enum Message {
     Click(Option<usize>),
     DoubleClick(Option<usize>),
     ClickRelease(Option<usize>),
+    CursorMoved(Point),
+    MouseAreaResized(Size, Rectangle),
     DragEnd(Option<usize>),
     Config(TabConfig),
     ContextAction(Action),
@@ -1772,6 +1776,9 @@ pub struct Tab {
     selected_clicked: bool,
     last_right_click: Option<usize>,
     search_context: Option<SearchContext>,
+    global_cursor_position: Option<Point>,
+    current_drag_rect: Option<Rectangle>,
+    viewport_rect: Option<Rectangle>,
 }
 
 fn calculate_dir_size(path: &Path, controller: Controller) -> Result<u64, String> {
@@ -1856,6 +1863,9 @@ impl Tab {
             selected_clicked: false,
             last_right_click: None,
             search_context: None,
+            global_cursor_position: None,
+            current_drag_rect: None,
+            viewport_rect: None,
         }
     }
 
@@ -2199,8 +2209,40 @@ impl Tab {
                     }
                 }
             }
+            Message::CursorMoved(pos) => {
+                self.global_cursor_position = Some(pos);
+
+                // we're currently dragging
+                if self.current_drag_rect.is_some() {
+                    if let Some(viewport) = self.viewport_rect {
+                        if !viewport.contains(pos) {
+                            // diff_y should be NEGATIVE here when close to y=0 (above the MouseArea)
+                            // and positive when below the viewport
+                            let diff_y = pos.y - viewport.y;
+                            let scroll_y: i8 = if diff_y > 0.0 {
+                                DRAG_SCROLL_DISTANCE as i8
+                            } else if diff_y < 0.0 {
+                                DRAG_SCROLL_DISTANCE as i8 * -1
+                            } else {
+                                0
+                            };
+
+                            commands.push(Command::Iced(
+                                scrollable::scroll_by(self.scrollable_id.clone(), AbsoluteOffset {
+                                    x: 0.0,
+                                    y: scroll_y as f32
+                                }).into(),
+                            ));
+                        }
+                    }
+                }
+            }
+            Message::MouseAreaResized(_size, viewport) => {
+                self.viewport_rect = Some(viewport);
+            }
             Message::DragEnd(_) => {
                 self.clicked = None;
+                self.current_drag_rect = None;
                 if let Some(ref mut items) = self.items_opt {
                     for item in items.iter_mut() {
                         item.overlaps_drag_rect = false;
@@ -2433,6 +2475,7 @@ impl Tab {
                 }
             }
             Message::Drag(rect_opt) => {
+                self.current_drag_rect = rect_opt;
                 if let Some(rect) = rect_opt {
                     self.context_menu = None;
                     self.location_context_menu_index = None;
@@ -4434,6 +4477,7 @@ impl Tab {
             .on_drag_end(|_| Message::DragEnd(None))
             .show_drag_rect(true)
             .on_release(|_| Message::ClickRelease(None))
+            .on_resize(Message::MouseAreaResized)
             .into(),
             true,
         )
@@ -4497,7 +4541,7 @@ impl Tab {
             .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_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);