Merge pull request #2300 from iced-rs/fix/pane-grid-drag

Fix `PaneGrid` mouse interaction when clicking a pane

2 files changed, 59 insertions, 99 deletions

diff --git a/widget/src/pane_grid.rs b/widget/src/pane_grid.rs
index 37562504..478a7024 100644
--- a/widget/src/pane_grid.rs
+++ b/widget/src/pane_grid.rs
@@ -46,6 +46,9 @@ use crate::core::{
     Vector, Widget,
 };
 
+const DRAG_DEADBAND_DISTANCE: f32 = 10.0;
+const THICKNESS_RATIO: f32 = 25.0;
+
 /// A collection of panes distributed using either vertical or horizontal splits
 /// to completely fill the space available.
 ///
@@ -532,8 +535,6 @@ pub fn update<'a, Message, T: Draggable>(
     on_drag: &Option<Box<dyn Fn(DragEvent) -> Message + 'a>>,
     on_resize: &Option<(f32, Box<dyn Fn(ResizeEvent) -> Message + 'a>)>,
 ) -> event::Status {
-    const DRAG_DEADBAND_DISTANCE: f32 = 10.0;
-
     let mut event_status = event::Status::Ignored;
 
     match event {
@@ -575,6 +576,7 @@ pub fn update<'a, Message, T: Draggable>(
                                 shell,
                                 contents,
                                 on_click,
+                                on_drag,
                             );
                         }
                     }
@@ -586,6 +588,7 @@ pub fn update<'a, Message, T: Draggable>(
                             shell,
                             contents,
                             on_click,
+                            on_drag,
                         );
                     }
                 }
@@ -594,38 +597,44 @@ pub fn update<'a, Message, T: Draggable>(
         Event::Mouse(mouse::Event::ButtonReleased(mouse::Button::Left))
         | Event::Touch(touch::Event::FingerLifted { .. })
         | Event::Touch(touch::Event::FingerLost { .. }) => {
-            if let Some((pane, _)) = action.picked_pane() {
+            if let Some((pane, origin)) = action.picked_pane() {
                 if let Some(on_drag) = on_drag {
                     if let Some(cursor_position) = cursor.position() {
-                        let event = if let Some(edge) =
-                            in_edge(layout, cursor_position)
+                        if cursor_position.distance(origin)
+                            > DRAG_DEADBAND_DISTANCE
                         {
-                            DragEvent::Dropped {
-                                pane,
-                                target: Target::Edge(edge),
-                            }
-                        } else {
-                            let dropped_region = contents
-                                .zip(layout.children())
-                                .find_map(|(target, layout)| {
-                                    layout_region(layout, cursor_position)
-                                        .map(|region| (target, region))
-                                });
-
-                            match dropped_region {
-                                Some(((target, _), region))
-                                    if pane != target =>
-                                {
-                                    DragEvent::Dropped {
-                                        pane,
-                                        target: Target::Pane(target, region),
+                            let event = if let Some(edge) =
+                                in_edge(layout, cursor_position)
+                            {
+                                DragEvent::Dropped {
+                                    pane,
+                                    target: Target::Edge(edge),
+                                }
+                            } else {
+                                let dropped_region = contents
+                                    .zip(layout.children())
+                                    .find_map(|(target, layout)| {
+                                        layout_region(layout, cursor_position)
+                                            .map(|region| (target, region))
+                                    });
+
+                                match dropped_region {
+                                    Some(((target, _), region))
+                                        if pane != target =>
+                                    {
+                                        DragEvent::Dropped {
+                                            pane,
+                                            target: Target::Pane(
+                                                target, region,
+                                            ),
+                                        }
                                     }
+                                    _ => DragEvent::Canceled { pane },
                                 }
-                                _ => DragEvent::Canceled { pane },
-                            }
-                        };
+                            };
 
-                        shell.publish(on_drag(event));
+                            shell.publish(on_drag(event));
+                        }
                     }
                 }
 
@@ -638,49 +647,7 @@ pub fn update<'a, Message, T: Draggable>(
         }
         Event::Mouse(mouse::Event::CursorMoved { .. })
         | Event::Touch(touch::Event::FingerMoved { .. }) => {
-            if let Some((_, origin)) = action.clicked_pane() {
-                if let Some(on_drag) = &on_drag {
-                    let bounds = layout.bounds();
-
-                    if let Some(cursor_position) = cursor.position_over(bounds)
-                    {
-                        let mut clicked_region = contents
-                            .zip(layout.children())
-                            .filter(|(_, layout)| {
-                                layout.bounds().contains(cursor_position)
-                            });
-
-                        if let Some(((pane, content), layout)) =
-                            clicked_region.next()
-                        {
-                            if content
-                                .can_be_dragged_at(layout, cursor_position)
-                            {
-                                let pane_position = layout.position();
-
-                                let new_origin = cursor_position
-                                    - Vector::new(
-                                        pane_position.x,
-                                        pane_position.y,
-                                    );
-
-                                if new_origin.distance(origin)
-                                    > DRAG_DEADBAND_DISTANCE
-                                {
-                                    *action = state::Action::Dragging {
-                                        pane,
-                                        origin,
-                                    };
-
-                                    shell.publish(on_drag(DragEvent::Picked {
-                                        pane,
-                                    }));
-                                }
-                            }
-                        }
-                    }
-                }
-            } else if let Some((_, on_resize)) = on_resize {
+            if let Some((_, on_resize)) = on_resize {
                 if let Some((split, _)) = action.picked_split() {
                     let bounds = layout.bounds();
 
@@ -755,6 +722,7 @@ fn click_pane<'a, Message, T>(
     shell: &mut Shell<'_, Message>,
     contents: impl Iterator<Item = (Pane, T)>,
     on_click: &Option<Box<dyn Fn(Pane) -> Message + 'a>>,
+    on_drag: &Option<Box<dyn Fn(DragEvent) -> Message + 'a>>,
 ) where
     T: Draggable,
 {
@@ -762,15 +730,21 @@ fn click_pane<'a, Message, T>(
         .zip(layout.children())
         .filter(|(_, layout)| layout.bounds().contains(cursor_position));
 
-    if let Some(((pane, _), layout)) = clicked_region.next() {
+    if let Some(((pane, content), layout)) = clicked_region.next() {
         if let Some(on_click) = &on_click {
             shell.publish(on_click(pane));
         }
 
-        let pane_position = layout.position();
-        let origin =
-            cursor_position - Vector::new(pane_position.x, pane_position.y);
-        *action = state::Action::Clicking { pane, origin };
+        if let Some(on_drag) = &on_drag {
+            if content.can_be_dragged_at(layout, cursor_position) {
+                *action = state::Action::Dragging {
+                    pane,
+                    origin: cursor_position,
+                };
+
+                shell.publish(on_drag(DragEvent::Picked { pane }));
+            }
+        }
     }
 }
 
@@ -783,7 +757,7 @@ pub fn mouse_interaction(
     spacing: f32,
     resize_leeway: Option<f32>,
 ) -> Option<mouse::Interaction> {
-    if action.clicked_pane().is_some() || action.picked_pane().is_some() {
+    if action.picked_pane().is_some() {
         return Some(mouse::Interaction::Grabbing);
     }
 
@@ -841,7 +815,13 @@ pub fn draw<Theme, Renderer, T>(
     Theme: StyleSheet,
     Renderer: crate::core::Renderer,
 {
-    let picked_pane = action.picked_pane();
+    let picked_pane = action.picked_pane().filter(|(_, origin)| {
+        cursor
+            .position()
+            .map(|position| position.distance(*origin))
+            .unwrap_or_default()
+            > DRAG_DEADBAND_DISTANCE
+    });
 
     let picked_split = action
         .picked_split()
@@ -962,8 +942,7 @@ pub fn draw<Theme, Renderer, T>(
         if let Some(cursor_position) = cursor.position() {
             let bounds = layout.bounds();
 
-            let translation = cursor_position
-                - Point::new(bounds.x + origin.x, bounds.y + origin.y);
+            let translation = cursor_position - Point::new(origin.x, origin.y);
 
             renderer.with_translation(translation, |renderer| {
                 renderer.with_layer(bounds, |renderer| {
@@ -1020,8 +999,6 @@ pub fn draw<Theme, Renderer, T>(
     }
 }
 
-const THICKNESS_RATIO: f32 = 25.0;
-
 fn in_edge(layout: Layout<'_>, cursor: Point) -> Option<Edge> {
     let bounds = layout.bounds();
 
diff --git a/widget/src/pane_grid/state.rs b/widget/src/pane_grid/state.rs
index 5d1fe254..481cd770 100644
--- a/widget/src/pane_grid/state.rs
+++ b/widget/src/pane_grid/state.rs
@@ -403,15 +403,6 @@ pub enum Action {
     ///
     /// [`PaneGrid`]: super::PaneGrid
     Idle,
-    /// A [`Pane`] in the [`PaneGrid`] is being clicked.
-    ///
-    /// [`PaneGrid`]: super::PaneGrid
-    Clicking {
-        /// The [`Pane`] being clicked.
-        pane: Pane,
-        /// The starting [`Point`] of the click interaction.
-        origin: Point,
-    },
     /// A [`Pane`] in the [`PaneGrid`] is being dragged.
     ///
     /// [`PaneGrid`]: super::PaneGrid
@@ -441,14 +432,6 @@ impl Action {
         }
     }
 
-    /// Returns the current [`Pane`] that is being clicked, if any.
-    pub fn clicked_pane(&self) -> Option<(Pane, Point)> {
-        match *self {
-            Action::Clicking { pane, origin, .. } => Some((pane, origin)),
-            _ => None,
-        }
-    }
-
     /// Returns the current [`Split`] that is being dragged, if any.
     pub fn picked_split(&self) -> Option<(Split, Axis)> {
         match *self {