Added set_cursor_icon(...) to Window (#3395)

# Objective

The window's cursor should be settable without having to implement a custom cursor icon solution. This will especially be helpful when creating user-interfaces that might like to use the cursor to denote some meaning (e.g., _clickable_, _resizable_, etc.).

## Solution

Added a `CursorIcon` enum that maps one-to-one to winit's `CursorIcon` enum, as well as a method to set/get it for the given `Window`.

crates/bevy_window/src/cursor.rs

@@ -0,0 +1,39 @@
+/// The icon to display for a window's cursor
+#[derive(Debug, Hash, PartialEq, Eq, Clone, Copy)]
+pub enum CursorIcon {
+    Default,
+    Crosshair,
+    Hand,
+    Arrow,
+    Move,
+    Text,
+    Wait,
+    Help,
+    Progress,
+    NotAllowed,
+    ContextMenu,
+    Cell,
+    VerticalText,
+    Alias,
+    Copy,
+    NoDrop,
+    Grab,
+    Grabbing,
+    AllScroll,
+    ZoomIn,
+    ZoomOut,
+    EResize,
+    NResize,
+    NeResize,
+    NwResize,
+    SResize,
+    SeResize,
+    SwResize,
+    WResize,
+    EwResize,
+    NsResize,
+    NeswResize,
+    NwseResize,
+    ColResize,
+    RowResize,
+}

crates/bevy_window/src/lib.rs

@@ -1,3 +1,4 @@
+mod cursor;
 mod event;
 mod raw_window_handle;
 mod system;
@@ -5,6 +6,7 @@ mod window;
 mod windows;
 
 pub use crate::raw_window_handle::*;
+pub use cursor::*;
 pub use event::*;
 pub use system::*;
 pub use window::*;
@@ -13,8 +15,8 @@ pub use windows::*;
 pub mod prelude {
     #[doc(hidden)]
     pub use crate::{
-        CursorEntered, CursorLeft, CursorMoved, FileDragAndDrop, ReceivedCharacter, Window,
-        WindowDescriptor, WindowMoved, Windows,
+        CursorEntered, CursorIcon, CursorLeft, CursorMoved, FileDragAndDrop, ReceivedCharacter,
+        Window, WindowDescriptor, WindowMoved, Windows,
     };
 }
 

crates/bevy_window/src/window.rs

@@ -19,6 +19,7 @@ impl WindowId {
     }
 }
 
+use crate::CursorIcon;
 use std::fmt;
 
 use crate::raw_window_handle::RawWindowHandleWrapper;
@@ -123,6 +124,7 @@ pub struct Window {
     vsync: bool,
     resizable: bool,
     decorations: bool,
+    cursor_icon: CursorIcon,
     cursor_visible: bool,
     cursor_locked: bool,
     physical_cursor_position: Option<DVec2>,
@@ -162,6 +164,9 @@ pub enum WindowCommand {
     SetCursorLockMode {
         locked: bool,
     },
+    SetCursorIcon {
+        icon: CursorIcon,
+    },
     SetCursorVisibility {
         visible: bool,
     },
@@ -222,6 +227,7 @@ impl Window {
             decorations: window_descriptor.decorations,
             cursor_visible: window_descriptor.cursor_visible,
             cursor_locked: window_descriptor.cursor_locked,
+            cursor_icon: CursorIcon::Default,
             physical_cursor_position: None,
             raw_window_handle: RawWindowHandleWrapper::new(raw_window_handle),
             focused: true,
@@ -474,6 +480,16 @@ impl Window {
         });
     }
 
+    #[inline]
+    pub fn cursor_icon(&self) -> CursorIcon {
+        self.cursor_icon
+    }
+
+    pub fn set_cursor_icon(&mut self, icon: CursorIcon) {
+        self.command_queue
+            .push(WindowCommand::SetCursorIcon { icon });
+    }
+
     /// The current mouse position, in physical pixels.
     #[inline]
     pub fn physical_cursor_position(&self) -> Option<DVec2> {

crates/bevy_winit/src/converters.rs

@@ -5,6 +5,7 @@ use bevy_input::{
     ElementState,
 };
 use bevy_math::Vec2;
+use bevy_window::CursorIcon;
 
 pub fn convert_keyboard_input(keyboard_input: &winit::event::KeyboardInput) -> KeyboardInput {
     KeyboardInput {
@@ -225,3 +226,43 @@ pub fn convert_virtual_key_code(virtual_key_code: winit::event::VirtualKeyCode)
         winit::event::VirtualKeyCode::Cut => KeyCode::Cut,
     }
 }
+
+pub fn convert_cursor_icon(cursor_icon: CursorIcon) -> winit::window::CursorIcon {
+    match cursor_icon {
+        CursorIcon::Default => winit::window::CursorIcon::Default,
+        CursorIcon::Crosshair => winit::window::CursorIcon::Crosshair,
+        CursorIcon::Hand => winit::window::CursorIcon::Hand,
+        CursorIcon::Arrow => winit::window::CursorIcon::Arrow,
+        CursorIcon::Move => winit::window::CursorIcon::Move,
+        CursorIcon::Text => winit::window::CursorIcon::Text,
+        CursorIcon::Wait => winit::window::CursorIcon::Wait,
+        CursorIcon::Help => winit::window::CursorIcon::Help,
+        CursorIcon::Progress => winit::window::CursorIcon::Progress,
+        CursorIcon::NotAllowed => winit::window::CursorIcon::NotAllowed,
+        CursorIcon::ContextMenu => winit::window::CursorIcon::ContextMenu,
+        CursorIcon::Cell => winit::window::CursorIcon::Cell,
+        CursorIcon::VerticalText => winit::window::CursorIcon::VerticalText,
+        CursorIcon::Alias => winit::window::CursorIcon::Alias,
+        CursorIcon::Copy => winit::window::CursorIcon::Copy,
+        CursorIcon::NoDrop => winit::window::CursorIcon::NoDrop,
+        CursorIcon::Grab => winit::window::CursorIcon::Grab,
+        CursorIcon::Grabbing => winit::window::CursorIcon::Grabbing,
+        CursorIcon::AllScroll => winit::window::CursorIcon::AllScroll,
+        CursorIcon::ZoomIn => winit::window::CursorIcon::ZoomIn,
+        CursorIcon::ZoomOut => winit::window::CursorIcon::ZoomOut,
+        CursorIcon::EResize => winit::window::CursorIcon::EResize,
+        CursorIcon::NResize => winit::window::CursorIcon::NResize,
+        CursorIcon::NeResize => winit::window::CursorIcon::NeResize,
+        CursorIcon::NwResize => winit::window::CursorIcon::NwResize,
+        CursorIcon::SResize => winit::window::CursorIcon::SResize,
+        CursorIcon::SeResize => winit::window::CursorIcon::SeResize,
+        CursorIcon::SwResize => winit::window::CursorIcon::SwResize,
+        CursorIcon::WResize => winit::window::CursorIcon::WResize,
+        CursorIcon::EwResize => winit::window::CursorIcon::EwResize,
+        CursorIcon::NsResize => winit::window::CursorIcon::NsResize,
+        CursorIcon::NeswResize => winit::window::CursorIcon::NeswResize,
+        CursorIcon::NwseResize => winit::window::CursorIcon::NwseResize,
+        CursorIcon::ColResize => winit::window::CursorIcon::ColResize,
+        CursorIcon::RowResize => winit::window::CursorIcon::RowResize,
+    }
+}

crates/bevy_winit/src/lib.rs

@@ -103,6 +103,10 @@ fn change_window(world: &mut World) {
                     let window = winit_windows.get_window(id).unwrap();
                     window.set_decorations(decorations);
                 }
+                bevy_window::WindowCommand::SetCursorIcon { icon } => {
+                    let window = winit_windows.get_window(id).unwrap();
+                    window.set_cursor_icon(converters::convert_cursor_icon(icon));
+                }
                 bevy_window::WindowCommand::SetCursorLockMode { locked } => {
                     let window = winit_windows.get_window(id).unwrap();
                     window

examples/window/window_settings.rs

@@ -13,6 +13,7 @@ fn main() {
         .add_plugins(DefaultPlugins)
         .add_system(change_title)
         .add_system(toggle_cursor)
+        .add_system(cycle_cursor_icon)
         .run();
 }
 
@@ -33,3 +34,30 @@ fn toggle_cursor(input: Res<Input<KeyCode>>, mut windows: ResMut<Windows>) {
         window.set_cursor_visibility(!window.cursor_visible());
     }
 }
+
+/// This system cycles the cursor's icon through a small set of icons when clicking
+fn cycle_cursor_icon(
+    input: Res<Input<MouseButton>>,
+    mut windows: ResMut<Windows>,
+    mut index: Local<usize>,
+) {
+    const ICONS: &[CursorIcon] = &[
+        CursorIcon::Default,
+        CursorIcon::Hand,
+        CursorIcon::Wait,
+        CursorIcon::Text,
+        CursorIcon::Copy,
+    ];
+    let window = windows.get_primary_mut().unwrap();
+    if input.just_pressed(MouseButton::Left) {
+        *index = (*index + 1) % ICONS.len();
+        window.set_cursor_icon(ICONS[*index]);
+    } else if input.just_pressed(MouseButton::Right) {
+        *index = if *index == 0 {
+            ICONS.len() - 1
+        } else {
+            *index - 1
+        };
+        window.set_cursor_icon(ICONS[*index]);
+    }
+}