Make CustomCursor variants CustomCursorImage/CustomCursorUrl structs (#17518)

# Objective

- Make `CustomCursor::Image` easier to work with by splitting the enum
variants off into `CustomCursorImage` and `CustomCursorUrl` structs and
deriving `Default` on those structs.
- Refs #17276.

## Testing

- Ran two examples: `cargo run --example custom_cursor_image
--features=custom_cursor` and `cargo run --example window_settings
--features=custom_cursor`
- CI.

---

## Migration Guide

The `CustomCursor` enum's variants now hold instances of
`CustomCursorImage` or `CustomCursorUrl`. Update your uses of
`CustomCursor` accordingly.

crates/bevy_winit/src/cursor.rs

@@ -37,7 +37,7 @@ use bevy_window::{SystemCursorIcon, Window};
 use tracing::warn;
 
 #[cfg(feature = "custom_cursor")]
-pub use crate::custom_cursor::CustomCursor;
+pub use crate::custom_cursor::{CustomCursor, CustomCursorImage};
 
 pub(crate) struct CursorPlugin;
 
@@ -91,14 +91,16 @@ fn update_cursors(
 
         let cursor_source = match cursor.as_ref() {
             #[cfg(feature = "custom_cursor")]
-            CursorIcon::Custom(CustomCursor::Image {
+            CursorIcon::Custom(CustomCursor::Image(c)) => {
+                let CustomCursorImage {
                     handle,
                     texture_atlas,
                     flip_x,
                     flip_y,
                     rect,
                     hotspot,
-            }) => {
+                } = c;
+
                 let cache_key = CustomCursorCacheKey::Image {
                     id: handle.id(),
                     texture_atlas_layout_id: texture_atlas.as_ref().map(|a| a.layout.id()),
@@ -155,14 +157,15 @@ fn update_cursors(
                 target_family = "wasm",
                 target_os = "unknown"
             ))]
-            CursorIcon::Custom(CustomCursor::Url { url, hotspot }) => {
-                let cache_key = CustomCursorCacheKey::Url(url.clone());
+            CursorIcon::Custom(CustomCursor::Url(c)) => {
+                let cache_key = CustomCursorCacheKey::Url(c.url.clone());
 
                 if cursor_cache.0.contains_key(&cache_key) {
                     CursorSource::CustomCached(cache_key)
                 } else {
                     use crate::CustomCursorExtWebSys;
-                    let source = WinitCustomCursor::from_url(url.clone(), hotspot.0, hotspot.1);
+                    let source =
+                        WinitCustomCursor::from_url(c.url.clone(), c.hotspot.0, c.hotspot.1);
                     CursorSource::Custom((cache_key, source))
                 }
             }

crates/bevy_winit/src/custom_cursor.rs

@@ -2,46 +2,57 @@ use bevy_app::{App, Plugin};
 use bevy_asset::{Assets, Handle};
 use bevy_image::{Image, TextureAtlas, TextureAtlasLayout, TextureAtlasPlugin};
 use bevy_math::{ops, Rect, URect, UVec2, Vec2};
-use bevy_reflect::Reflect;
+use bevy_reflect::{std_traits::ReflectDefault, Reflect};
 use wgpu_types::TextureFormat;
 
 use crate::{cursor::CursorIcon, state::CustomCursorCache};
 
-/// Custom cursor image data.
-#[derive(Debug, Clone, Reflect, PartialEq, Eq, Hash)]
-pub enum CustomCursor {
-    /// Image to use as a cursor.
-    Image {
-        /// The image must be in 8 bit int or 32 bit float rgba. PNG images
-        /// work well for this.
-        handle: Handle<Image>,
-        /// The (optional) texture atlas used to render the image.
-        texture_atlas: Option<TextureAtlas>,
+/// A custom cursor created from an image.
+#[derive(Debug, Clone, Default, Reflect, PartialEq, Eq, Hash)]
+#[reflect(Debug, Default, Hash, PartialEq)]
+pub struct CustomCursorImage {
+    /// Handle to the image to use as the cursor. The image must be in 8 bit int
+    /// or 32 bit float rgba. PNG images work well for this.
+    pub handle: Handle<Image>,
+    /// An optional texture atlas used to render the image.
+    pub texture_atlas: Option<TextureAtlas>,
     /// Whether the image should be flipped along its x-axis.
-        flip_x: bool,
+    pub flip_x: bool,
     /// Whether the image should be flipped along its y-axis.
-        flip_y: bool,
-        /// An optional rectangle representing the region of the image to
-        /// render, instead of rendering the full image. This is an easy one-off
-        /// alternative to using a [`TextureAtlas`].
+    pub flip_y: bool,
+    /// An optional rectangle representing the region of the image to render,
+    /// instead of rendering the full image. This is an easy one-off alternative
+    /// to using a [`TextureAtlas`].
     ///
     /// When used with a [`TextureAtlas`], the rect is offset by the atlas's
     /// minimal (top-left) corner position.
-        rect: Option<URect>,
-        /// X and Y coordinates of the hotspot in pixels. The hotspot must be
-        /// within the image bounds.
-        hotspot: (u16, u16),
-    },
-    #[cfg(all(target_family = "wasm", target_os = "unknown"))]
-    /// A URL to an image to use as the cursor.
-    Url {
-        /// Web URL to an image to use as the cursor. PNGs preferred. Cursor
+    pub rect: Option<URect>,
+    /// X and Y coordinates of the hotspot in pixels. The hotspot must be within
+    /// the image bounds.
+    pub hotspot: (u16, u16),
+}
+
+#[cfg(all(target_family = "wasm", target_os = "unknown"))]
+/// A custom cursor created from a URL.
+#[derive(Debug, Clone, Default, Reflect, PartialEq, Eq, Hash)]
+#[reflect(Debug, Default, Hash, PartialEq)]
+pub struct CustomCursorUrl {
+    /// Web URL to an image to use as the cursor. PNGs are preferred. Cursor
     /// creation can fail if the image is invalid or not reachable.
-        url: String,
-        /// X and Y coordinates of the hotspot in pixels. The hotspot must be
-        /// within the image bounds.
-        hotspot: (u16, u16),
-    },
+    pub url: String,
+    /// X and Y coordinates of the hotspot in pixels. The hotspot must be within
+    /// the image bounds.
+    pub hotspot: (u16, u16),
+}
+
+/// Custom cursor image data.
+#[derive(Debug, Clone, Reflect, PartialEq, Eq, Hash)]
+pub enum CustomCursor {
+    /// Use an image as the cursor.
+    Image(CustomCursorImage),
+    #[cfg(all(target_family = "wasm", target_os = "unknown"))]
+    /// Use a URL to an image as the cursor.
+    Url(CustomCursorUrl),
 }
 
 impl From<CustomCursor> for CursorIcon {

examples/window/custom_cursor_image.rs

@@ -3,8 +3,10 @@
 
 use std::time::Duration;
 
-use bevy::winit::cursor::CustomCursor;
-use bevy::{prelude::*, winit::cursor::CursorIcon};
+use bevy::{
+    prelude::*,
+    winit::cursor::{CursorIcon, CustomCursor, CustomCursorImage},
+};
 
 fn main() {
     App::new()
@@ -39,7 +41,7 @@ fn setup_cursor_icon(
     let animation_config = AnimationConfig::new(0, 199, 1, 4);
 
     commands.entity(*window).insert((
-        CursorIcon::Custom(CustomCursor::Image {
+        CursorIcon::Custom(CustomCursor::Image(CustomCursorImage {
             // Image to use as the cursor.
             handle: asset_server
                 .load("cursors/kenney_crosshairPack/Tilesheet/crosshairs_tilesheet_white.png"),
@@ -56,7 +58,7 @@ fn setup_cursor_icon(
             // The hotspot is the point in the cursor image that will be
             // positioned at the mouse cursor's position.
             hotspot: (0, 0),
-        }),
+        })),
         animation_config,
     ));
 }
@@ -112,15 +114,11 @@ impl AnimationConfig {
 /// `last_sprite_index`.
 fn execute_animation(time: Res<Time>, mut query: Query<(&mut AnimationConfig, &mut CursorIcon)>) {
     for (mut config, mut cursor_icon) in &mut query {
-        if let CursorIcon::Custom(CustomCursor::Image {
-            ref mut texture_atlas,
-            ..
-        }) = *cursor_icon
-        {
+        if let CursorIcon::Custom(CustomCursor::Image(ref mut image)) = *cursor_icon {
             config.frame_timer.tick(time.delta());
 
             if config.frame_timer.finished() {
-                if let Some(atlas) = texture_atlas {
+                if let Some(atlas) = image.texture_atlas.as_mut() {
                     atlas.index += config.increment;
 
                     if atlas.index > config.last_sprite_index {
@@ -141,18 +139,19 @@ fn toggle_texture_atlas(
 ) {
     if input.just_pressed(KeyCode::KeyT) {
         for mut cursor_icon in &mut query {
-            if let CursorIcon::Custom(CustomCursor::Image {
-                ref mut texture_atlas,
-                ..
-            }) = *cursor_icon
-            {
-                *texture_atlas = match texture_atlas.take() {
+            if let CursorIcon::Custom(CustomCursor::Image(ref mut image)) = *cursor_icon {
+                match image.texture_atlas.take() {
                     Some(a) => {
+                        // Save the current texture atlas.
                         *cached_atlas = Some(a.clone());
-                        None
                     }
-                    None => cached_atlas.take(),
-                };
+                    None => {
+                        // Restore the cached texture atlas.
+                        if let Some(cached_a) = cached_atlas.take() {
+                            image.texture_atlas = Some(cached_a);
+                        }
+                    }
+                }
             }
         }
     }
@@ -164,8 +163,8 @@ fn toggle_flip_x(
 ) {
     if input.just_pressed(KeyCode::KeyX) {
         for mut cursor_icon in &mut query {
-            if let CursorIcon::Custom(CustomCursor::Image { ref mut flip_x, .. }) = *cursor_icon {
-                *flip_x = !*flip_x;
+            if let CursorIcon::Custom(CustomCursor::Image(ref mut image)) = *cursor_icon {
+                image.flip_x = !image.flip_x;
             }
         }
     }
@@ -177,8 +176,8 @@ fn toggle_flip_y(
 ) {
     if input.just_pressed(KeyCode::KeyY) {
         for mut cursor_icon in &mut query {
-            if let CursorIcon::Custom(CustomCursor::Image { ref mut flip_y, .. }) = *cursor_icon {
-                *flip_y = !*flip_y;
+            if let CursorIcon::Custom(CustomCursor::Image(ref mut image)) = *cursor_icon {
+                image.flip_y = !image.flip_y;
             }
         }
     }
@@ -214,15 +213,15 @@ fn cycle_rect(input: Res<ButtonInput<KeyCode>>, mut query: Query<&mut CursorIcon
     ];
 
     for mut cursor_icon in &mut query {
-        if let CursorIcon::Custom(CustomCursor::Image { ref mut rect, .. }) = *cursor_icon {
+        if let CursorIcon::Custom(CustomCursor::Image(ref mut image)) = *cursor_icon {
             let next_rect = SECTIONS
                 .iter()
                 .cycle()
-                .skip_while(|&&corner| corner != *rect)
+                .skip_while(|&&corner| corner != image.rect)
                 .nth(1) // move to the next element
                 .unwrap_or(&None);
 
-            *rect = *next_rect;
+            image.rect = *next_rect;
         }
     }
 }

examples/window/window_settings.rs

@@ -2,7 +2,7 @@
 //! the mouse pointer in various ways.
 
 #[cfg(feature = "custom_cursor")]
-use bevy::winit::cursor::CustomCursor;
+use bevy::winit::cursor::{CustomCursor, CustomCursorImage};
 use bevy::{
     diagnostic::{FrameCount, FrameTimeDiagnosticsPlugin, LogDiagnosticsPlugin},
     prelude::*,
@@ -163,14 +163,11 @@ fn init_cursor_icons(
         SystemCursorIcon::Wait.into(),
         SystemCursorIcon::Text.into(),
         #[cfg(feature = "custom_cursor")]
-        CustomCursor::Image {
+        CustomCursor::Image(CustomCursorImage {
             handle: asset_server.load("branding/icon.png"),
-            texture_atlas: None,
-            flip_x: false,
-            flip_y: false,
-            rect: None,
             hotspot: (128, 128),
-        }
+            ..Default::default()
+        })
         .into(),
     ]));
 }