feat: add a window drag resize task

core/src/window.rs

@@ -8,6 +8,7 @@ mod level;
 mod mode;
 mod position;
 mod redraw_request;
+mod resize_direction;
 mod user_attention;
 
 pub use event::Event;
@@ -17,5 +18,6 @@ pub use level::Level;
 pub use mode::Mode;
 pub use position::Position;
 pub use redraw_request::RedrawRequest;
+pub use resize_direction::ResizeDirection;
 pub use settings::Settings;
 pub use user_attention::UserAttention;

core/src/window/resize_direction.rs

@@ -0,0 +1,27 @@
+/// Defines the orientation that a window resize will be performed.
+#[derive(Debug, Clone, Copy)]
+pub enum ResizeDirection {
+    /// The window will be resized along the eastern ( right ) edge.
+    East,
+
+    /// The window will be resized along the eastern ( top ) edge.
+    North,
+
+    /// The window will be resized at the northeastern ( top-right ) corner.
+    NorthEast,
+
+    /// The window will be resized at the northwestern ( top-left ) corner.
+    NorthWest,
+
+    /// The window will be resized along the southern ( bottom ) edge.
+    South,
+
+    /// The window will be resized at the southeastern ( bottom-right ) corner.
+    SouthEast,
+
+    /// The window will be resized at the southwestern ( bottom-left ) corner.
+    SouthWest,
+
+    /// The window will be resized along the western ( left ) edge.
+    West,
+}

runtime/src/window.rs

@@ -5,7 +5,7 @@ pub use screenshot::Screenshot;
 
 use crate::core::time::Instant;
 use crate::core::window::{
-    Event, Icon, Id, Level, Mode, Settings, UserAttention,
+    Event, Icon, Id, Level, Mode, ResizeDirection, Settings, UserAttention,
 };
 use crate::core::{Point, Size};
 use crate::futures::event;
@@ -39,6 +39,13 @@ pub enum Action {
     /// button was pressed immediately before this function is called.
     Drag(Id),
 
+    /// Resize the window with the left mouse button until the button is
+    /// released.
+    ///
+    /// There’s no guarantee that this will work unless the left mouse
+    /// button was pressed immediately before this function is called.
+    DragResize(Id, ResizeDirection),
+
     /// Resize the window to the given logical dimensions.
     Resize(Id, Size),
 
@@ -264,6 +271,11 @@ pub fn drag<T>(id: Id) -> Task<T> {
     task::effect(crate::Action::Window(Action::Drag(id)))
 }
 
+/// Begins resizing the window while the left mouse button is held.
+pub fn drag_resize<T>(id: Id, direction: ResizeDirection) -> Task<T> {
+    task::effect(crate::Action::Window(Action::DragResize(id, direction)))
+}
+
 /// Resizes the window to the given logical dimensions.
 pub fn resize<T>(id: Id, new_size: Size) -> Task<T> {
     task::effect(crate::Action::Window(Action::Resize(id, new_size)))

winit/src/conversion.rs

@@ -1112,7 +1112,7 @@ pub fn native_key_code(
     }
 }
 
-/// Converts some [`UserAttention`] into it's `winit` counterpart.
+/// Converts some [`UserAttention`] into its `winit` counterpart.
 ///
 /// [`UserAttention`]: window::UserAttention
 pub fn user_attention(
@@ -1128,6 +1128,32 @@ pub fn user_attention(
     }
 }
 
+/// Converts some [`ResizeDirection`] into its `winit` counterpart.
+///
+/// [`ResizeDirection`]: window::ResizeDirection
+pub fn resize_direction(
+    resize_direction: window::ResizeDirection,
+) -> winit::window::ResizeDirection {
+    match resize_direction {
+        window::ResizeDirection::East => winit::window::ResizeDirection::East,
+        window::ResizeDirection::North => winit::window::ResizeDirection::North,
+        window::ResizeDirection::NorthEast => {
+            winit::window::ResizeDirection::NorthEast
+        }
+        window::ResizeDirection::NorthWest => {
+            winit::window::ResizeDirection::NorthWest
+        }
+        window::ResizeDirection::South => winit::window::ResizeDirection::South,
+        window::ResizeDirection::SouthEast => {
+            winit::window::ResizeDirection::SouthEast
+        }
+        window::ResizeDirection::SouthWest => {
+            winit::window::ResizeDirection::SouthWest
+        }
+        window::ResizeDirection::West => winit::window::ResizeDirection::West,
+    }
+}
+
 /// Converts some [`window::Icon`] into it's `winit` counterpart.
 ///
 /// Returns `None` if there is an error during the conversion.

winit/src/program.rs

@@ -1285,6 +1285,13 @@ fn run_action<P, C>(
                     let _ = window.raw.drag_window();
                 }
             }
+            window::Action::DragResize(id, direction) => {
+                if let Some(window) = window_manager.get_mut(id) {
+                    let _ = window.raw.drag_resize_window(
+                        conversion::resize_direction(direction),
+                    );
+                }
+            }
             window::Action::Resize(id, size) => {
                 if let Some(window) = window_manager.get_mut(id) {
                     let _ = window.raw.request_inner_size(