Merge pull request #812 from ellieplayswow/feature/drag-scroll

adding in drag-scroll functionality when cursor is outside of scrollable viewport

src/app.rs

@@ -18,6 +18,7 @@ use cosmic::{
     app::{self, context_drawer, message, Core, Task},
     cosmic_config, cosmic_theme, executor,
     iced::{
+        self,
         clipboard::dnd::DndAction,
         event,
         futures::{self, SinkExt},
@@ -54,6 +55,7 @@ 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 +279,7 @@ pub enum Message {
     Config(Config),
     Copy(Option<Entity>),
     CosmicSettings(&'static str),
+    CursorMoved(Point),
     Cut(Option<Entity>),
     DesktopConfig(DesktopConfig),
     DesktopViewOptions,
@@ -330,6 +333,7 @@ pub enum Message {
     Rename(Option<Entity>),
     ReplaceResult(ReplaceResult),
     RestoreFromTrash(Option<Entity>),
+    ScrollTab(i16),
     SearchActivate,
     SearchClear,
     SearchInput(String),
@@ -548,6 +552,7 @@ pub struct App {
     tab_dnd_hover: Option<(Entity, Instant)>,
     nav_drag_id: DragId,
     tab_drag_id: DragId,
+    auto_scroll_speed: Option<i16>
 }
 
 impl App {
@@ -1626,6 +1631,7 @@ impl Application for App {
             tab_dnd_hover: None,
             nav_drag_id: DragId::new(),
             tab_drag_id: DragId::new(),
+            auto_scroll_speed: None,
         };
 
         let mut commands = vec![app.update_config()];
@@ -1926,6 +1932,10 @@ 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);
@@ -2788,6 +2798,10 @@ impl Application for App {
                     self.operation(Operation::Restore { items: trash_items });
                 }
             }
+            Message::ScrollTab(scroll_speed) => {
+                let entity = self.tab_model.active();
+                return self.update(Message::TabMessage(Some(entity), tab::Message::ScrollTab((scroll_speed as f32) / 10.0)));
+            }
             Message::SearchActivate => {
                 return if self.search_get().is_none() {
                     self.search_set_active(Some(String::new()))
@@ -2925,6 +2939,17 @@ impl Application for App {
                             config_set!(favorites, favorites);
                             commands.push(self.update_config());
                         }
+                        tab::Command::AutoScroll(scroll_speed) => {
+                            // converting an f32 to an i16 here by multiplying by 10 and casting to i16
+                            // further resolution isn't necessary
+                            if let Some(scroll_speed_float) = scroll_speed {
+                                self.auto_scroll_speed = Some((scroll_speed_float * 10.0) as i16);
+                            }
+                            else {
+                                self.auto_scroll_speed = None;
+                            }
+
+                        }
                         tab::Command::ChangeLocation(tab_title, tab_path, selection_paths) => {
                             self.activate_nav_model_location(&tab_path);
 
@@ -4536,7 +4561,8 @@ impl Application for App {
                         }
                         _ => None,
                     }
-                }
+                },
+                Event::Mouse(CursorMoved { position: pos }) => Some(Message::CursorMoved(pos)),
                 _ => None,
             }),
             Config::subscription().map(|update| {
@@ -4707,6 +4733,13 @@ impl Application for App {
             ),
         ];
 
+        if let Some(scroll_speed) = self.auto_scroll_speed {
+            subscriptions.push(
+                iced::time::every(time::Duration::from_millis(10)).with(scroll_speed)
+                    .map(|(scroll_speed, _)| Message::ScrollTab(scroll_speed))
+            );
+        }
+
         for (key, mounter) in MOUNTERS.iter() {
             subscriptions.push(
                 mounter.subscription().with(*key).map(

src/mouse_area.rs

@@ -50,6 +50,7 @@ pub struct MouseArea<'a, Message> {
     on_enter: Option<Box<dyn OnEnterExit<'a, Message>>>,
     on_exit: Option<Box<dyn OnEnterExit<'a, Message>>>,
     show_drag_rect: bool,
+    cursor_offset: Option<Point>
 }
 
 impl<'a, Message> MouseArea<'a, Message> {
@@ -185,6 +186,11 @@ impl<'a, Message> MouseArea<'a, Message> {
         self
     }
 
+    pub fn cursor_offset(mut self, offset: Option<Point>) -> Self {
+        self.cursor_offset = offset;
+        self
+    }
+
     /// Sets the widget's unique identifier.
     #[must_use]
     pub fn with_id(mut self, id: Id) -> Self {
@@ -199,8 +205,8 @@ 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
@@ -215,6 +221,8 @@ impl<'a, Message, F> OnEnterExit<'a, Message> for F where F: Fn() -> Message + '
 #[derive(Default)]
 struct State {
     last_position: Option<Point>,
+    last_virtual_position: Option<Point>,
+    last_in_bounds_position: Option<Point>,
     drag_initiated: Option<Point>,
     modifiers: Modifiers,
     prev_click: Option<(mouse::Click, Instant)>,
@@ -224,7 +232,7 @@ struct State {
 impl State {
     fn drag_rect(&self, cursor: mouse::Cursor) -> Option<Rectangle> {
         if let Some(drag_source) = self.drag_initiated {
-            if let Some(position) = cursor.position() {
+            if let Some(position) = cursor.position().or(self.last_virtual_position) {
                 if position.distance(drag_source) > 1.0 {
                     let min_x = drag_source.x.min(position.x);
                     let max_x = drag_source.x.max(position.x);
@@ -292,6 +300,7 @@ impl<'a, Message> MouseArea<'a, Message> {
             on_exit: None,
             on_scroll: None,
             show_drag_rect: false,
+            cursor_offset: None
         }
     }
 }
@@ -374,6 +383,7 @@ where
             cursor,
             shell,
             tree.state.downcast_mut::<State>(),
+            viewport,
         )
     }
 
@@ -493,6 +503,7 @@ 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 +511,7 @@ 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));
         }
     }
 
@@ -520,6 +531,42 @@ fn update<Message: Clone>(
             _ => {}
         }
         state.last_position = position_in;
+
+        // if we have a cursor_offset, we need to calculate our "virtual" position
+        // (where we think the ABSOLUTE cursor is) - we'll take the last in bounds position and
+        // clamp it to the layout bounds
+        if let Some(offset) = widget.cursor_offset {
+            if let Some(in_bounds_pos) = state.last_in_bounds_position {
+                let mut new_virtual_pos = Point {
+                    x: in_bounds_pos.x + offset.x,
+                    y: in_bounds_pos.y + offset.y
+                };
+
+                // clamp to the viewport
+                new_virtual_pos.x = if new_virtual_pos.x > (layout_bounds.width + layout_bounds.x) {
+                    layout_bounds.width + layout_bounds.x
+                } else if new_virtual_pos.x < 0.0 {
+                    0.0
+                } else {
+                    new_virtual_pos.x
+                };
+
+                new_virtual_pos.y = if new_virtual_pos.y > (layout_bounds.height + layout_bounds.y) {
+                    layout_bounds.height + layout_bounds.y
+                } else if new_virtual_pos.y < 0.0 {
+                    0.0
+                } else {
+                    new_virtual_pos.y
+                };
+
+                state.last_virtual_position = Some(new_virtual_pos);
+            }
+        }
+
+        // set the last in bounds position to be the ABSOLUTE version of position_in
+        if position_in.is_some() {
+            state.last_in_bounds_position = cursor.position_over(layout_bounds);
+        }
     }
 
     if state.drag_initiated.is_none() && !cursor.is_over(layout_bounds) {

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: f32 = 15.0;
+
 //TODO: adjust for locales?
 const DATE_TIME_FORMAT: &str = "%b %-d, %-Y, %-I:%M %p";
 const TIME_FORMAT: &str = "%-I:%M %p";
@@ -1098,6 +1100,7 @@ pub enum Command {
     Action(Action),
     AddNetworkDrive,
     AddToSidebar(PathBuf),
+    AutoScroll(Option<f32>),
     ChangeLocation(String, Location, Option<Vec<PathBuf>>),
     DropFiles(PathBuf, ClipboardPaste),
     EmptyTrash,
@@ -1121,6 +1124,8 @@ pub enum Message {
     Click(Option<usize>),
     DoubleClick(Option<usize>),
     ClickRelease(Option<usize>),
+    CursorMoved(Point),
+    MouseAreaResized(Size, Rectangle),
     DragEnd(Option<usize>),
     Config(TabConfig),
     ContextAction(Action),
@@ -1153,6 +1158,7 @@ pub enum Message {
     RightClick(Option<usize>),
     MiddleClick(usize),
     Scroll(Viewport),
+    ScrollTab(f32),
     ScrollToFocus,
     SearchContext(Location, SearchContextWrapper),
     SearchReady(bool),
@@ -1772,6 +1778,12 @@ 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>,
+    virtual_cursor_offset: Option<Point>,
+    last_scroll_position: Option<Point>,
+    last_scroll_offset: Option<Point>,
 }
 
 fn calculate_dir_size(path: &Path, controller: Controller) -> Result<u64, String> {
@@ -1856,6 +1868,12 @@ impl Tab {
             selected_clicked: false,
             last_right_click: None,
             search_context: None,
+            global_cursor_position: None,
+            current_drag_rect: None,
+            viewport_rect: None,
+            virtual_cursor_offset: None,
+            last_scroll_position: None,
+            last_scroll_offset: None
         }
     }
 
@@ -2199,13 +2217,120 @@ 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) {
+                            if pos.y < viewport.y || pos.y > (viewport.y + viewport.height) {
+                                // if our mouse is above the scrollable viewport, we want to scroll up
+                                let drag_start_point = Point {
+                                    x: viewport.x,
+                                    y: viewport.y
+                                };
+                                // 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 - drag_start_point.y;
+                                let scroll_y: f32 = if diff_y > 0.0 {
+                                    DRAG_SCROLL_DISTANCE
+                                } else if diff_y < 0.0 {
+                                    DRAG_SCROLL_DISTANCE * -1.0
+                                } else {
+                                    0.0
+                                };
+
+                                let mut new_offset = Point {
+                                    x: 0.0,
+                                    y: scroll_y
+                                };
+
+                                if let Some(virtual_cursor_offset) = self.virtual_cursor_offset {
+                                    new_offset = Point {
+                                        x: new_offset.x + virtual_cursor_offset.x,
+                                        y: new_offset.y + virtual_cursor_offset.y,
+                                    };
+                                }
+
+                                if let Some(last_scroll_position) = self.last_scroll_position {
+                                    new_offset.x = pos.x - last_scroll_position.x;
+                                }
+
+                                self.virtual_cursor_offset = Some(new_offset);
+                                self.last_scroll_offset = Some(new_offset);
+
+                                commands.push(Command::AutoScroll(Some(scroll_y)));
+                            }
+                            else {
+                                if let Some(last_scroll_offset) = self.last_scroll_offset {
+                                    if let Some(last_scroll_position) = self.last_scroll_position {
+                                        self.virtual_cursor_offset = Some(Point {
+                                            x: 0.0,
+                                            y: (pos.y - last_scroll_position.y + last_scroll_offset.y)
+                                        });
+                                    }
+
+                                }
+                                else {
+                                    if let Some(last_scroll_position) = self.last_scroll_position {
+                                        self.virtual_cursor_offset = Some(Point {
+                                            x: 0.0,
+                                            y: (pos.y - last_scroll_position.y)
+                                        });
+                                    }
+                                    else {
+                                        self.virtual_cursor_offset = Some(Point {
+                                            x: 0.0,
+                                            y: 0.0
+                                        });
+                                    }
+                                }
+
+                                commands.push(Command::AutoScroll(None));
+                            }
+                        }
+                        else {
+                            // reset our virtual cursor offset when we're back in bounds
+                            self.virtual_cursor_offset = None;
+                            self.last_scroll_position = Some(pos);
+                            self.last_scroll_offset = None;
+
+                            commands.push(Command::AutoScroll(None));
+                        }
+                    }
+                }
+            }
+            Message::MouseAreaResized(_size, viewport) => {
+                // if we have a scroll position, we want to subtract it from the viewport
+                // so that we don't desync when swapping
+                if let Some(scroll_pos) = self.scroll_opt {
+                    self.viewport_rect = Some(Rectangle {
+                        x: viewport.x - scroll_pos.x,
+                        y: viewport.y - scroll_pos.y,
+                        width: viewport.width,
+                        height: viewport.height
+                    });
+                }
+                else {
+                    self.viewport_rect = Some(viewport);
+                }
+
+            }
             Message::DragEnd(_) => {
                 self.clicked = None;
+                self.virtual_cursor_offset = None;
+                self.last_scroll_offset = None;
+                self.last_scroll_position = 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;
                     }
                 }
+
+                commands.push(Command::AutoScroll(None));
             }
             Message::DoubleClick(click_i_opt) => {
                 if let Some(clicked_item) = self
@@ -2433,6 +2558,7 @@ 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;
@@ -2835,6 +2961,14 @@ impl Tab {
             Message::Scroll(viewport) => {
                 self.scroll_opt = Some(viewport.absolute_offset());
             }
+            Message::ScrollTab(scroll_speed) => {
+                commands.push(Command::Iced(
+                    scrollable::scroll_by(self.scrollable_id.clone(), AbsoluteOffset {
+                        x: 0.0,
+                        y: scroll_speed
+                    }).into(),
+                ));
+            }
             Message::ScrollToFocus => {
                 if let Some(offset) = self.select_focus_scroll() {
                     commands.push(Command::Iced(
@@ -4104,6 +4238,8 @@ impl Tab {
                 .on_drag_end(|_| Message::DragEnd(None))
                 .show_drag_rect(true)
                 .on_release(|_| Message::ClickRelease(None))
+                .on_resize(Message::MouseAreaResized)
+                .cursor_offset(self.virtual_cursor_offset)
                 .into(),
             true,
         )
@@ -4434,6 +4570,8 @@ impl Tab {
             .on_drag_end(|_| Message::DragEnd(None))
             .show_drag_rect(true)
             .on_release(|_| Message::ClickRelease(None))
+            .on_resize(Message::MouseAreaResized)
+            .cursor_offset(self.virtual_cursor_offset)
             .into(),
             true,
         )
@@ -4497,7 +4635,7 @@ 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);