feat: position field on WindowAttribute

.changes/position.md

@@ -0,0 +1,6 @@
+---
+"wry": minor
+---
+
+Add position field on WindowAttribute
+

src/application/window.rs

@@ -71,6 +71,31 @@ pub struct WindowAttributes {
   /// The default is `None`.
   pub max_inner_size: Option<Size>,
 
+  /// The desired position of the window. If this is `None`, some platform-specific position
+  /// will be chosen.
+  ///
+  /// The default is `None`.
+  ///
+  /// ## Platform-specific
+  ///
+  /// - **macOS**: The top left corner position of the window content, the window's "inner"
+  /// position. The window title bar will be placed above it.
+  /// The window will be positioned such that it fits on screen, maintaining
+  /// set `inner_size` if any.
+  /// If you need to precisely position the top left corner of the whole window you have to
+  /// use [`Window::set_outer_position`] after creating the window.
+  /// - **Windows**: The top left corner position of the window title bar, the window's "outer"
+  /// position.
+  /// There may be a small gap between this position and the window due to the specifics of the
+  /// Window Manager.
+  /// - **X11**: The top left corner of the window, the window's "outer" position.
+  /// - **Others**: Ignored.
+  ///
+  /// See [`Window::set_outer_position`].
+  ///
+  /// [`Window::set_outer_position`]: crate::window::Window::set_outer_position
+  pub position: Option<Position>,
+
   /// Whether the window is resizable or not.
   ///
   /// The default is `true`.
@@ -125,6 +150,7 @@ impl Default for WindowAttributes {
       inner_size: None,
       min_inner_size: None,
       max_inner_size: None,
+      position: None,
       resizable: true,
       title: "winit window".to_owned(),
       maximized: false,
@@ -194,6 +220,17 @@ impl WindowBuilder {
     self
   }
 
+  /// Sets a desired initial position for the window.
+  ///
+  /// See [`WindowAttributes::position`] for details.
+  ///
+  /// [`WindowAttributes::position`]: crate::window::WindowAttributes::position
+  #[inline]
+  pub fn with_position<P: Into<Position>>(mut self, position: P) -> Self {
+    self.window.position = Some(position.into());
+    self
+  }
+
   /// Sets whether the window is resizable or not.
   ///
   /// See [`Window::set_resizable`] for details.
@@ -408,6 +445,12 @@ impl Window {
       geom_mask,
     );
 
+    // Set Position
+    if let Some(position) = attributes.position {
+      let (x, y): (i32, i32) = position.to_physical::<i32>(win_scale_factor as f64).into();
+      window.move_(x, y);
+    }
+
     // Set Transparent
     if attributes.transparent {
       if let Some(screen) = window.get_screen() {