feat(x11): Add Window::drag_resize_window (#2515)

examples/window_drag_resize.rs

@@ -0,0 +1,141 @@
+//! Demonstrates capability to create in-app draggable regions for client-side decoration support.
+
+use simple_logger::SimpleLogger;
+use winit::{
+    event::{
+        ElementState, Event, KeyboardInput, MouseButton, StartCause, VirtualKeyCode, WindowEvent,
+    },
+    event_loop::{ControlFlow, EventLoop},
+    window::{CursorIcon, ResizeDirection, WindowBuilder},
+};
+
+const BORDER: f64 = 8.0;
+
+fn main() {
+    SimpleLogger::new().init().unwrap();
+    let event_loop = EventLoop::new();
+
+    let window = WindowBuilder::new()
+        .with_inner_size(winit::dpi::LogicalSize::new(600.0, 400.0))
+        .with_min_inner_size(winit::dpi::LogicalSize::new(400.0, 200.0))
+        .with_decorations(false)
+        .build(&event_loop)
+        .unwrap();
+
+    let mut border = false;
+    let mut cursor_location = None;
+
+    event_loop.run(move |event, _, control_flow| match event {
+        Event::NewEvents(StartCause::Init) => {
+            eprintln!("Press 'B' to toggle borderless")
+        }
+        Event::WindowEvent { event, .. } => match event {
+            WindowEvent::CloseRequested => *control_flow = ControlFlow::Exit,
+            WindowEvent::CursorMoved { position, .. } => {
+                if !window.is_decorated() {
+                    let new_location =
+                        cursor_resize_direction(window.inner_size(), position, BORDER);
+
+                    if new_location != cursor_location {
+                        cursor_location = new_location;
+                        window.set_cursor_icon(cursor_direction_icon(cursor_location))
+                    }
+                }
+            }
+
+            WindowEvent::MouseInput {
+                state: ElementState::Pressed,
+                button: MouseButton::Left,
+                ..
+            } => {
+                if let Some(dir) = cursor_location {
+                    let _res = window.drag_resize_window(dir);
+                }
+            }
+            WindowEvent::KeyboardInput {
+                input:
+                    KeyboardInput {
+                        state: ElementState::Released,
+                        virtual_keycode: Some(VirtualKeyCode::B),
+                        ..
+                    },
+                ..
+            } => {
+                border = !border;
+                window.set_decorations(border);
+            }
+            _ => (),
+        },
+        _ => (),
+    });
+}
+
+fn cursor_direction_icon(resize_direction: Option<ResizeDirection>) -> CursorIcon {
+    match resize_direction {
+        Some(resize_direction) => match resize_direction {
+            ResizeDirection::East => CursorIcon::EResize,
+            ResizeDirection::North => CursorIcon::NResize,
+            ResizeDirection::NorthEast => CursorIcon::NeResize,
+            ResizeDirection::NorthWest => CursorIcon::NwResize,
+            ResizeDirection::South => CursorIcon::SResize,
+            ResizeDirection::SouthEast => CursorIcon::SeResize,
+            ResizeDirection::SouthWest => CursorIcon::SwResize,
+            ResizeDirection::West => CursorIcon::WResize,
+        },
+        None => CursorIcon::Default,
+    }
+}
+
+fn cursor_resize_direction(
+    win_size: winit::dpi::PhysicalSize<u32>,
+    position: winit::dpi::PhysicalPosition<f64>,
+    border_size: f64,
+) -> Option<ResizeDirection> {
+    enum XDirection {
+        West,
+        East,
+        Default,
+    }
+
+    enum YDirection {
+        North,
+        South,
+        Default,
+    }
+
+    let xdir = if position.x < border_size {
+        XDirection::West
+    } else if position.x > (win_size.width as f64 - border_size) {
+        XDirection::East
+    } else {
+        XDirection::Default
+    };
+
+    let ydir = if position.y < border_size {
+        YDirection::North
+    } else if position.y > (win_size.height as f64 - border_size) {
+        YDirection::South
+    } else {
+        YDirection::Default
+    };
+
+    Some(match xdir {
+        XDirection::West => match ydir {
+            YDirection::North => ResizeDirection::NorthWest,
+            YDirection::South => ResizeDirection::SouthWest,
+            YDirection::Default => ResizeDirection::West,
+        },
+
+        XDirection::East => match ydir {
+            YDirection::North => ResizeDirection::NorthEast,
+            YDirection::South => ResizeDirection::SouthEast,
+            YDirection::Default => ResizeDirection::East,
+        },
+
+        XDirection::Default => match ydir {
+            YDirection::North => ResizeDirection::North,
+            YDirection::South => ResizeDirection::South,
+            YDirection::Default => return None,
+        },
+    })
+}