bevy_winit/
cursor.rs

1//! Components to customize winit cursor
2
3use crate::{
4    converters::convert_system_cursor_icon,
5    state::{CursorSource, PendingCursor},
6};
7#[cfg(feature = "custom_cursor")]
8use crate::{
9    custom_cursor::{
10        calculate_effective_rect, extract_and_transform_rgba_pixels, extract_rgba_pixels,
11        transform_hotspot, CustomCursorPlugin,
12    },
13    state::{CustomCursorCache, CustomCursorCacheKey},
14    WinitCustomCursor,
15};
16use bevy_app::{App, Last, Plugin};
17#[cfg(feature = "custom_cursor")]
18use bevy_asset::Assets;
19#[cfg(feature = "custom_cursor")]
20use bevy_ecs::system::Res;
21use bevy_ecs::{
22    change_detection::DetectChanges,
23    component::Component,
24    entity::Entity,
25    observer::Trigger,
26    query::With,
27    reflect::ReflectComponent,
28    system::{Commands, Local, Query},
29    world::{OnRemove, Ref},
30};
31#[cfg(feature = "custom_cursor")]
32use bevy_image::{Image, TextureAtlasLayout};
33use bevy_platform::collections::HashSet;
34use bevy_reflect::{std_traits::ReflectDefault, Reflect};
35use bevy_window::{SystemCursorIcon, Window};
36#[cfg(feature = "custom_cursor")]
37use tracing::warn;
38
39#[cfg(feature = "custom_cursor")]
40pub use crate::custom_cursor::{CustomCursor, CustomCursorImage};
41
42#[cfg(all(
43    feature = "custom_cursor",
44    target_family = "wasm",
45    target_os = "unknown"
46))]
47pub use crate::custom_cursor::CustomCursorUrl;
48
49pub(crate) struct CursorPlugin;
50
51impl Plugin for CursorPlugin {
52    fn build(&self, app: &mut App) {
53        #[cfg(feature = "custom_cursor")]
54        app.add_plugins(CustomCursorPlugin);
55
56        app.register_type::<CursorIcon>()
57            .add_systems(Last, update_cursors);
58
59        app.add_observer(on_remove_cursor_icon);
60    }
61}
62
63/// Insert into a window entity to set the cursor for that window.
64#[derive(Component, Debug, Clone, Reflect, PartialEq, Eq)]
65#[reflect(Component, Debug, Default, PartialEq, Clone)]
66pub enum CursorIcon {
67    #[cfg(feature = "custom_cursor")]
68    /// Custom cursor image.
69    Custom(CustomCursor),
70    /// System provided cursor icon.
71    System(SystemCursorIcon),
72}
73
74impl Default for CursorIcon {
75    fn default() -> Self {
76        CursorIcon::System(Default::default())
77    }
78}
79
80impl From<SystemCursorIcon> for CursorIcon {
81    fn from(icon: SystemCursorIcon) -> Self {
82        CursorIcon::System(icon)
83    }
84}
85
86fn update_cursors(
87    mut commands: Commands,
88    windows: Query<(Entity, Ref<CursorIcon>), With<Window>>,
89    #[cfg(feature = "custom_cursor")] cursor_cache: Res<CustomCursorCache>,
90    #[cfg(feature = "custom_cursor")] images: Res<Assets<Image>>,
91    #[cfg(feature = "custom_cursor")] texture_atlases: Res<Assets<TextureAtlasLayout>>,
92    mut queue: Local<HashSet<Entity>>,
93) {
94    for (entity, cursor) in windows.iter() {
95        if !(queue.remove(&entity) || cursor.is_changed()) {
96            continue;
97        }
98
99        let cursor_source = match cursor.as_ref() {
100            #[cfg(feature = "custom_cursor")]
101            CursorIcon::Custom(CustomCursor::Image(c)) => {
102                let CustomCursorImage {
103                    handle,
104                    texture_atlas,
105                    flip_x,
106                    flip_y,
107                    rect,
108                    hotspot,
109                } = c;
110
111                let cache_key = CustomCursorCacheKey::Image {
112                    id: handle.id(),
113                    texture_atlas_layout_id: texture_atlas.as_ref().map(|a| a.layout.id()),
114                    texture_atlas_index: texture_atlas.as_ref().map(|a| a.index),
115                    flip_x: *flip_x,
116                    flip_y: *flip_y,
117                    rect: *rect,
118                };
119
120                if cursor_cache.0.contains_key(&cache_key) {
121                    CursorSource::CustomCached(cache_key)
122                } else {
123                    let Some(image) = images.get(handle) else {
124                        warn!(
125                            "Cursor image {handle:?} is not loaded yet and couldn't be used. Trying again next frame."
126                        );
127                        queue.insert(entity);
128                        continue;
129                    };
130
131                    let (rect, needs_sub_image) =
132                        calculate_effective_rect(&texture_atlases, image, texture_atlas, rect);
133
134                    let (maybe_rgba, hotspot) = if *flip_x || *flip_y || needs_sub_image {
135                        (
136                            extract_and_transform_rgba_pixels(image, *flip_x, *flip_y, rect),
137                            transform_hotspot(*hotspot, *flip_x, *flip_y, rect),
138                        )
139                    } else {
140                        (extract_rgba_pixels(image), *hotspot)
141                    };
142
143                    let Some(rgba) = maybe_rgba else {
144                        warn!("Cursor image {handle:?} not accepted because it's not rgba8 or rgba32float format");
145                        continue;
146                    };
147
148                    let source = match WinitCustomCursor::from_rgba(
149                        rgba,
150                        rect.width() as u16,
151                        rect.height() as u16,
152                        hotspot.0,
153                        hotspot.1,
154                    ) {
155                        Ok(source) => source,
156                        Err(err) => {
157                            warn!("Cursor image {handle:?} is invalid: {err}");
158                            continue;
159                        }
160                    };
161
162                    CursorSource::Custom((cache_key, source))
163                }
164            }
165            #[cfg(all(
166                feature = "custom_cursor",
167                target_family = "wasm",
168                target_os = "unknown"
169            ))]
170            CursorIcon::Custom(CustomCursor::Url(c)) => {
171                let cache_key = CustomCursorCacheKey::Url(c.url.clone());
172
173                if cursor_cache.0.contains_key(&cache_key) {
174                    CursorSource::CustomCached(cache_key)
175                } else {
176                    use crate::CustomCursorExtWebSys;
177                    let source =
178                        WinitCustomCursor::from_url(c.url.clone(), c.hotspot.0, c.hotspot.1);
179                    CursorSource::Custom((cache_key, source))
180                }
181            }
182            CursorIcon::System(system_cursor_icon) => {
183                CursorSource::System(convert_system_cursor_icon(*system_cursor_icon))
184            }
185        };
186
187        commands
188            .entity(entity)
189            .insert(PendingCursor(Some(cursor_source)));
190    }
191}
192
193/// Resets the cursor to the default icon when `CursorIcon` is removed.
194fn on_remove_cursor_icon(trigger: Trigger<OnRemove, CursorIcon>, mut commands: Commands) {
195    // Use `try_insert` to avoid panic if the window is being destroyed.
196    commands
197        .entity(trigger.target())
198        .try_insert(PendingCursor(Some(CursorSource::System(
199            convert_system_cursor_icon(SystemCursorIcon::Default),
200        ))));
201}
bevy_winit/cursor.rs

bevy_winit/
cursor.rs
