Introduce `window::Level` enum

... and add `level` field to `window::Settings`

5 files changed, 46 insertions, 16 deletions

diff --git a/core/src/window.rs b/core/src/window.rs
index 81bd7e3d..a6dbdfb4 100644
--- a/core/src/window.rs
+++ b/core/src/window.rs
@@ -2,12 +2,14 @@
 pub mod icon;
 
 mod event;
+mod level;
 mod mode;
 mod redraw_request;
 mod user_attention;
 
 pub use event::Event;
 pub use icon::Icon;
+pub use level::Level;
 pub use mode::Mode;
 pub use redraw_request::RedrawRequest;
 pub use user_attention::UserAttention;
diff --git a/core/src/window/level.rs b/core/src/window/level.rs
new file mode 100644
index 00000000..3878ecac
--- /dev/null
+++ b/core/src/window/level.rs
@@ -0,0 +1,19 @@
+/// A window level groups windows with respect to their z-position.
+///
+/// The relative ordering between windows in different window levels is fixed.
+/// The z-order of a window within the same window level may change dynamically
+/// on user interaction.
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
+pub enum Level {
+    /// The default behavior.
+    #[default]
+    Normal,
+
+    /// The window will always be below normal windows.
+    ///
+    /// This is useful for a widget-based app.
+    AlwaysOnBottom,
+
+    /// The window will always be on top of normal windows.
+    AlwaysOnTop,
+}
diff --git a/src/window/settings.rs b/src/window/settings.rs
index 3c8da62f..458b9232 100644
--- a/src/window/settings.rs
+++ b/src/window/settings.rs
@@ -1,4 +1,4 @@
-use crate::window::{Icon, Position};
+use crate::window::{Icon, Level, Position};
 
 pub use iced_winit::settings::PlatformSpecific;
 
@@ -29,8 +29,8 @@ pub struct Settings {
     /// Whether the window should be transparent.
     pub transparent: bool,
 
-    /// Whether the window will always be on top of other windows.
-    pub always_on_top: bool,
+    /// The window [`Level`].
+    pub level: Level,
 
     /// The icon of the window.
     pub icon: Option<Icon>,
@@ -50,7 +50,7 @@ impl Default for Settings {
             resizable: true,
             decorations: true,
             transparent: false,
-            always_on_top: false,
+            level: Level::default(),
             icon: None,
             platform_specific: Default::default(),
         }
@@ -68,7 +68,7 @@ impl From<Settings> for iced_winit::settings::Window {
             resizable: settings.resizable,
             decorations: settings.decorations,
             transparent: settings.transparent,
-            always_on_top: settings.always_on_top,
+            level: settings.level,
             icon: settings.icon.map(Icon::into),
             platform_specific: settings.platform_specific,
         }
diff --git a/winit/src/conversion.rs b/winit/src/conversion.rs
index a9262184..904aa184 100644
--- a/winit/src/conversion.rs
+++ b/winit/src/conversion.rs
@@ -140,6 +140,19 @@ pub fn window_event(
     }
 }
 
+/// Converts a [`window::Level`] to a [`winit`] window level.
+///
+/// [`winit`]: https://github.com/rust-windowing/winit
+pub fn window_level(level: window::Level) -> winit::window::WindowLevel {
+    match level {
+        window::Level::Normal => winit::window::WindowLevel::Normal,
+        window::Level::AlwaysOnBottom => {
+            winit::window::WindowLevel::AlwaysOnBottom
+        }
+        window::Level::AlwaysOnTop => winit::window::WindowLevel::AlwaysOnTop,
+    }
+}
+
 /// Converts a [`Position`] to a [`winit`] logical position for a given monitor.
 ///
 /// [`winit`]: https://github.com/rust-windowing/winit
diff --git a/winit/src/settings.rs b/winit/src/settings.rs
index 13be3932..40b3d487 100644
--- a/winit/src/settings.rs
+++ b/winit/src/settings.rs
@@ -22,11 +22,11 @@ mod platform;
 pub use platform::PlatformSpecific;
 
 use crate::conversion;
-use crate::core::window::Icon;
+use crate::core::window::{Icon, Level};
 use crate::Position;
 
 use winit::monitor::MonitorHandle;
-use winit::window::{WindowBuilder, WindowLevel};
+use winit::window::WindowBuilder;
 
 use std::fmt;
 
@@ -81,8 +81,8 @@ pub struct Window {
     /// Whether the window should be transparent.
     pub transparent: bool,
 
-    /// Whether the window will always be on top of other windows.
-    pub always_on_top: bool,
+    /// The window [`Level`].
+    pub level: Level,
 
     /// The window icon, which is also usually used in the taskbar
     pub icon: Option<Icon>,
@@ -102,7 +102,7 @@ impl fmt::Debug for Window {
             .field("resizable", &self.resizable)
             .field("decorations", &self.decorations)
             .field("transparent", &self.transparent)
-            .field("always_on_top", &self.always_on_top)
+            .field("level", &self.level)
             .field("icon", &self.icon.is_some())
             .field("platform_specific", &self.platform_specific)
             .finish()
@@ -121,10 +121,6 @@ impl Window {
 
         let (width, height) = self.size;
 
-        let window_level = match self.always_on_top {
-            true => WindowLevel::AlwaysOnTop,
-            false => WindowLevel::Normal,
-        };
         window_builder = window_builder
             .with_title(title)
             .with_inner_size(winit::dpi::LogicalSize { width, height })
@@ -132,7 +128,7 @@ impl Window {
             .with_decorations(self.decorations)
             .with_transparent(self.transparent)
             .with_window_icon(self.icon.and_then(conversion::icon))
-            .with_window_level(window_level)
+            .with_window_level(conversion::window_level(self.level))
             .with_visible(self.visible);
 
         if let Some(position) = conversion::position(
@@ -211,7 +207,7 @@ impl Default for Window {
             resizable: true,
             decorations: true,
             transparent: false,
-            always_on_top: false,
+            level: Level::default(),
             icon: None,
             platform_specific: Default::default(),
         }