Struct Hovered 

pub struct Hovered(pub bool);

A component that allows users to use regular Bevy change detection to determine when the pointer enters or leaves an entity. Users should insert this component on an entity to indicate interest in knowing about hover state changes.

The component’s boolean value will be true whenever the pointer is currently directly hovering over the entity, or any of the entity’s descendants (as defined by the ChildOf relationship). This is consistent with the behavior of the CSS :hover pseudo-class, which applies to the element and all of its descendants.

The contained boolean value is guaranteed to only be mutated when the pointer enters or leaves the entity, allowing Bevy change detection to be used efficiently. This is in contrast to the HoverMap resource, which is updated every frame.

Typically, a simple hoverable entity or widget will have this component added to it. More complex widgets can have this component added to each hoverable part.

The computational cost of keeping the Hovered components up to date is relatively cheap, and linear in the number of entities that have the Hovered component inserted.

Tuple Fields

0: bool

Implementations

impl Hovered

pub fn get(&self) -> bool

Get whether the entity is currently hovered.

Examples found in repository

examples/ui/standard_widgets.rs (line 235)

fn update_button_style(
    mut buttons: Query<
        (
            Has<Pressed>,
            &Hovered,
            Has<InteractionDisabled>,
            &mut BackgroundColor,
            &mut BorderColor,
            &Children,
        ),
        (
            Or<(
                Changed<Pressed>,
                Changed<Hovered>,
                Added<InteractionDisabled>,
            )>,
            With<DemoButton>,
        ),
    >,
    mut text_query: Query<&mut Text>,
) {
    for (pressed, hovered, disabled, mut color, mut border_color, children) in &mut buttons {
        let mut text = text_query.get_mut(children[0]).unwrap();
        set_button_style(
            disabled,
            hovered.get(),
            pressed,
            &mut color,
            &mut border_color,
            &mut text,
        );
    }
}

/// Supplementary system to detect removed marker components
fn update_button_style2(
    mut buttons: Query<
        (
            Has<Pressed>,
            &Hovered,
            Has<InteractionDisabled>,
            &mut BackgroundColor,
            &mut BorderColor,
            &Children,
        ),
        With<DemoButton>,
    >,
    mut removed_depressed: RemovedComponents<Pressed>,
    mut removed_disabled: RemovedComponents<InteractionDisabled>,
    mut text_query: Query<&mut Text>,
) {
    removed_depressed
        .read()
        .chain(removed_disabled.read())
        .for_each(|entity| {
            if let Ok((pressed, hovered, disabled, mut color, mut border_color, children)) =
                buttons.get_mut(entity)
            {
                let mut text = text_query.get_mut(children[0]).unwrap();
                set_button_style(
                    disabled,
                    hovered.get(),
                    pressed,
                    &mut color,
                    &mut border_color,
                    &mut text,
                );
            }
        });
}

examples/ui/standard_widgets_observers.rs (line 185)

fn button_on_interaction<E: EntityEvent, C: Component>(
    event: On<E, C>,
    mut buttons: Query<
        (
            &Hovered,
            Has<InteractionDisabled>,
            Has<Pressed>,
            &mut BackgroundColor,
            &mut BorderColor,
            &Children,
        ),
        With<DemoButton>,
    >,
    mut text_query: Query<&mut Text>,
) {
    if let Ok((hovered, disabled, pressed, mut color, mut border_color, children)) =
        buttons.get_mut(event.event_target())
    {
        if children.is_empty() {
            return;
        }
        let Ok(mut text) = text_query.get_mut(children[0]) else {
            return;
        };
        let hovered = hovered.get();
        // These "removal event checks" exist because the `Remove` event is triggered _before_ the component is actually
        // removed, meaning it still shows up in the query. We're investigating the best way to improve this scenario.
        let pressed = pressed && !(E::is::<Remove>() && C::is::<Pressed>());
        let disabled = disabled && !(E::is::<Remove>() && C::is::<InteractionDisabled>());
        match (disabled, hovered, pressed) {
            // Disabled button
            (true, _, _) => {
                **text = "Disabled".to_string();
                *color = NORMAL_BUTTON.into();
                border_color.set_all(GRAY);
            }

            // Pressed and hovered button
            (false, true, true) => {
                **text = "Press".to_string();
                *color = PRESSED_BUTTON.into();
                border_color.set_all(RED);
            }

            // Hovered, unpressed button
            (false, true, false) => {
                **text = "Hover".to_string();
                *color = HOVERED_BUTTON.into();
                border_color.set_all(WHITE);
            }

            // Unhovered button (either pressed or not).
            (false, false, _) => {
                **text = "Button".to_string();
                *color = NORMAL_BUTTON.into();
                border_color.set_all(BLACK);
            }
        }
    }
}

/// Create a demo slider
fn slider(min: f32, max: f32, value: f32) -> impl Bundle {
    (
        Node {
            display: Display::Flex,
            flex_direction: FlexDirection::Column,
            justify_content: JustifyContent::Center,
            align_items: AlignItems::Stretch,
            justify_items: JustifyItems::Center,
            column_gap: px(4),
            height: px(12),
            width: percent(30),
            ..default()
        },
        Name::new("Slider"),
        Hovered::default(),
        DemoSlider,
        Slider::default(),
        SliderValue(value),
        SliderRange::new(min, max),
        TabIndex(0),
        Children::spawn((
            // Slider background rail
            Spawn((
                Node {
                    height: px(6),
                    ..default()
                },
                BackgroundColor(SLIDER_TRACK), // Border color for the checkbox
                BorderRadius::all(px(3)),
            )),
            // Invisible track to allow absolute placement of thumb entity. This is narrower than
            // the actual slider, which allows us to position the thumb entity using simple
            // percentages, without having to measure the actual width of the slider thumb.
            Spawn((
                Node {
                    display: Display::Flex,
                    position_type: PositionType::Absolute,
                    left: px(0),
                    // Track is short by 12px to accommodate the thumb.
                    right: px(12),
                    top: px(0),
                    bottom: px(0),
                    ..default()
                },
                children![(
                    // Thumb
                    DemoSliderThumb,
                    SliderThumb,
                    Node {
                        display: Display::Flex,
                        width: px(12),
                        height: px(12),
                        position_type: PositionType::Absolute,
                        left: percent(0), // This will be updated by the slider's value
                        ..default()
                    },
                    BorderRadius::MAX,
                    BackgroundColor(SLIDER_THUMB),
                )],
            )),
        )),
    )
}

fn slider_on_interaction<E: EntityEvent, C: Component>(
    event: On<E, C>,
    sliders: Query<(Entity, &Hovered, Has<InteractionDisabled>), With<DemoSlider>>,
    children: Query<&Children>,
    mut thumbs: Query<(&mut BackgroundColor, Has<DemoSliderThumb>), Without<DemoSlider>>,
) {
    if let Ok((slider_ent, hovered, disabled)) = sliders.get(event.event_target()) {
        // These "removal event checks" exist because the `Remove` event is triggered _before_ the component is actually
        // removed, meaning it still shows up in the query. We're investigating the best way to improve this scenario.
        let disabled = disabled && !(E::is::<Remove>() && C::is::<InteractionDisabled>());
        for child in children.iter_descendants(slider_ent) {
            if let Ok((mut thumb_bg, is_thumb)) = thumbs.get_mut(child)
                && is_thumb
            {
                thumb_bg.0 = thumb_color(disabled, hovered.0);
            }
        }
    }
}

fn slider_on_change_value<C: Component>(
    insert: On<Insert, C>,
    sliders: Query<(Entity, &SliderValue, &SliderRange), With<DemoSlider>>,
    children: Query<&Children>,
    mut thumbs: Query<(&mut Node, Has<DemoSliderThumb>), Without<DemoSlider>>,
) {
    if let Ok((slider_ent, value, range)) = sliders.get(insert.entity) {
        for child in children.iter_descendants(slider_ent) {
            if let Ok((mut thumb_node, is_thumb)) = thumbs.get_mut(child)
                && is_thumb
            {
                thumb_node.left = percent(range.thumb_position(value.0) * 100.0);
            }
        }
    }
}

fn thumb_color(disabled: bool, hovered: bool) -> Color {
    match (disabled, hovered) {
        (true, _) => GRAY.into(),

        (false, true) => SLIDER_THUMB.lighter(0.3),

        _ => SLIDER_THUMB,
    }
}

/// Create a demo checkbox
fn checkbox(asset_server: &AssetServer, caption: &str) -> impl Bundle {
    (
        Node {
            display: Display::Flex,
            flex_direction: FlexDirection::Row,
            justify_content: JustifyContent::FlexStart,
            align_items: AlignItems::Center,
            align_content: AlignContent::Center,
            column_gap: px(4),
            ..default()
        },
        Name::new("Checkbox"),
        Hovered::default(),
        DemoCheckbox,
        Checkbox,
        TabIndex(0),
        Children::spawn((
            Spawn((
                // Checkbox outer
                Node {
                    display: Display::Flex,
                    width: px(16),
                    height: px(16),
                    border: UiRect::all(px(2)),
                    ..default()
                },
                BorderColor::all(CHECKBOX_OUTLINE), // Border color for the checkbox
                BorderRadius::all(px(3)),
                children![
                    // Checkbox inner
                    (
                        Node {
                            display: Display::Flex,
                            width: px(8),
                            height: px(8),
                            position_type: PositionType::Absolute,
                            left: px(2),
                            top: px(2),
                            ..default()
                        },
                        BackgroundColor(Srgba::NONE.into()),
                    ),
                ],
            )),
            Spawn((
                Text::new(caption),
                TextFont {
                    font: asset_server.load("fonts/FiraSans-Bold.ttf"),
                    font_size: 20.0,
                    ..default()
                },
            )),
        )),
    )
}

fn checkbox_on_interaction<E: EntityEvent, C: Component>(
    event: On<E, C>,
    checkboxes: Query<
        (&Hovered, Has<InteractionDisabled>, Has<Checked>, &Children),
        With<DemoCheckbox>,
    >,
    mut borders: Query<(&mut BorderColor, &mut Children), Without<DemoCheckbox>>,
    mut marks: Query<&mut BackgroundColor, (Without<DemoCheckbox>, Without<Children>)>,
) {
    if let Ok((hovered, disabled, checked, children)) = checkboxes.get(event.event_target()) {
        let hovered = hovered.get();
        // These "removal event checks" exist because the `Remove` event is triggered _before_ the component is actually
        // removed, meaning it still shows up in the query. We're investigating the best way to improve this scenario.
        let checked = checked && !(E::is::<Remove>() && C::is::<Checked>());
        let disabled = disabled && !(E::is::<Remove>() && C::is::<InteractionDisabled>());

        let Some(border_id) = children.first() else {
            return;
        };

        let Ok((mut border_color, border_children)) = borders.get_mut(*border_id) else {
            return;
        };

        let Some(mark_id) = border_children.first() else {
            warn!("Checkbox does not have a mark entity.");
            return;
        };

        let Ok(mut mark_bg) = marks.get_mut(*mark_id) else {
            warn!("Checkbox mark entity lacking a background color.");
            return;
        };

        let color: Color = if disabled {
            // If the checkbox is disabled, use a lighter color
            CHECKBOX_OUTLINE.with_alpha(0.2)
        } else if hovered {
            // If hovering, use a lighter color
            CHECKBOX_OUTLINE.lighter(0.2)
        } else {
            // Default color for the checkbox
            CHECKBOX_OUTLINE
        };

        // Update the background color of the check mark
        border_color.set_all(color);

        let mark_color: Color = match (disabled, checked) {
            (true, true) => CHECKBOX_CHECK.with_alpha(0.5),
            (false, true) => CHECKBOX_CHECK,
            (_, false) => Srgba::NONE.into(),
        };

        if mark_bg.0 != mark_color {
            // Update the color of the check mark
            mark_bg.0 = mark_color;
        }
    }
}

Trait Implementations

impl Clone for Hovered

fn clone(&self) -> Hovered

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Component for Hovered

where Hovered: Send + Sync + 'static,

const STORAGE_TYPE: StorageType = bevy_ecs::component::StorageType::Table

A constant indicating the storage type used for this component.

type Mutability = Immutable

A marker type to assist Bevy with determining if this component is mutable, or immutable. Mutable components will have Component<Mutability = Mutable>, while immutable components will instead have Component<Mutability = Immutable>.

fn register_required_components( _requiree: ComponentId, required_components: &mut RequiredComponentsRegistrator<'_, '_>, )

Registers required components.

fn clone_behavior() -> ComponentCloneBehavior

Called when registering this component, allowing to override clone function (or disable cloning altogether) for this component.

fn on_add() -> Option<for<'w> fn(DeferredWorld<'w>, HookContext)>

Gets the on_add ComponentHook for this Component if one is defined.

fn on_insert() -> Option<for<'w> fn(DeferredWorld<'w>, HookContext)>

Gets the on_insert ComponentHook for this Component if one is defined.

fn on_replace() -> Option<for<'w> fn(DeferredWorld<'w>, HookContext)>

Gets the on_replace ComponentHook for this Component if one is defined.

fn on_remove() -> Option<for<'w> fn(DeferredWorld<'w>, HookContext)>

Gets the on_remove ComponentHook for this Component if one is defined.

fn on_despawn() -> Option<for<'w> fn(DeferredWorld<'w>, HookContext)>

Gets the on_despawn ComponentHook for this Component if one is defined.

fn map_entities<E>(_this: &mut Self, _mapper: &mut E)

where E: EntityMapper,

Maps the entities on this component using the given EntityMapper. This is used to remap entities in contexts like scenes and entity cloning. When deriving Component, this is populated by annotating fields containing entities with #[entities]

impl Debug for Hovered

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl Default for Hovered

fn default() -> Hovered

Returns the “default value” for a type.

impl FromArg for Hovered

type This<'from_arg> = Hovered

The type to convert into.

fn from_arg(arg: Arg<'_>) -> Result<<Hovered as FromArg>::This<'_>, ArgError>

Creates an item from an argument.

impl FromReflect for Hovered

fn from_reflect(reflect: &(dyn PartialReflect + 'static)) -> Option<Hovered>

Constructs a concrete instance of Self from a reflected value.

fn take_from_reflect( reflect: Box<dyn PartialReflect>, ) -> Result<Self, Box<dyn PartialReflect>>

Attempts to downcast the given value to Self using, constructing the value using from_reflect if that fails.

impl GetOwnership for Hovered

fn ownership() -> Ownership

Returns the ownership of Self.

impl GetTypeRegistration for Hovered

fn get_type_registration() -> TypeRegistration

Returns the default TypeRegistration for this type.

fn register_type_dependencies(registry: &mut TypeRegistry)

Registers other types needed by this type.

impl IntoReturn for Hovered

fn into_return<'into_return>(self) -> Return<'into_return>

where Hovered: 'into_return,

Converts Self into a Return value.

impl PartialEq for Hovered

fn eq(&self, other: &Hovered) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl PartialReflect for Hovered

fn get_represented_type_info(&self) -> Option<&'static TypeInfo>

Returns the TypeInfo of the type represented by this value.

fn try_apply( &mut self, value: &(dyn PartialReflect + 'static), ) -> Result<(), ApplyError>

Tries to apply a reflected value to this value.

fn reflect_kind(&self) -> ReflectKind

Returns a zero-sized enumeration of “kinds” of type.

fn reflect_ref(&self) -> ReflectRef<'_>

Returns an immutable enumeration of “kinds” of type.

fn reflect_mut(&mut self) -> ReflectMut<'_>

Returns a mutable enumeration of “kinds” of type.

fn reflect_owned(self: Box<Hovered>) -> ReflectOwned

Returns an owned enumeration of “kinds” of type.

fn try_into_reflect( self: Box<Hovered>, ) -> Result<Box<dyn Reflect>, Box<dyn PartialReflect>>

Attempts to cast this type to a boxed, fully-reflected value.

fn try_as_reflect(&self) -> Option<&(dyn Reflect + 'static)>

Attempts to cast this type to a fully-reflected value.

fn try_as_reflect_mut(&mut self) -> Option<&mut (dyn Reflect + 'static)>

Attempts to cast this type to a mutable, fully-reflected value.

fn into_partial_reflect(self: Box<Hovered>) -> Box<dyn PartialReflect>

Casts this type to a boxed, reflected value.

fn as_partial_reflect(&self) -> &(dyn PartialReflect + 'static)

Casts this type to a reflected value.

fn as_partial_reflect_mut(&mut self) -> &mut (dyn PartialReflect + 'static)

Casts this type to a mutable, reflected value.

fn reflect_partial_eq( &self, value: &(dyn PartialReflect + 'static), ) -> Option<bool>

Returns a “partial equality” comparison result.

fn debug(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Debug formatter for the value.

fn reflect_clone(&self) -> Result<Box<dyn Reflect>, ReflectCloneError>

Attempts to clone Self using reflection.

fn apply(&mut self, value: &(dyn PartialReflect + 'static))

Applies a reflected value to this value.

fn to_dynamic(&self) -> Box<dyn PartialReflect>

Converts this reflected value into its dynamic representation based on its kind.

fn reflect_clone_and_take<T>(&self) -> Result<T, ReflectCloneError>

where T: 'static, Self: Sized + TypePath,

For a type implementing PartialReflect, combines reflect_clone and take in a useful fashion, automatically constructing an appropriate ReflectCloneError if the downcast fails.

fn reflect_hash(&self) -> Option<u64>

Returns a hash of the value (which includes the type).

fn is_dynamic(&self) -> bool

Indicates whether or not this type is a dynamic type.

impl Reflect for Hovered

fn into_any(self: Box<Hovered>) -> Box<dyn Any>

Returns the value as a Box<dyn Any>.

fn as_any(&self) -> &(dyn Any + 'static)

Returns the value as a &dyn Any.

fn as_any_mut(&mut self) -> &mut (dyn Any + 'static)

Returns the value as a &mut dyn Any.

fn into_reflect(self: Box<Hovered>) -> Box<dyn Reflect>

Casts this type to a boxed, fully-reflected value.

fn as_reflect(&self) -> &(dyn Reflect + 'static)

Casts this type to a fully-reflected value.

fn as_reflect_mut(&mut self) -> &mut (dyn Reflect + 'static)

Casts this type to a mutable, fully-reflected value.

fn set(&mut self, value: Box<dyn Reflect>) -> Result<(), Box<dyn Reflect>>

Performs a type-checked assignment of a reflected value to this value.

impl TupleStruct for Hovered

fn field(&self, index: usize) -> Option<&(dyn PartialReflect + 'static)>

Returns a reference to the value of the field with index index as a &dyn Reflect.

fn field_mut( &mut self, index: usize, ) -> Option<&mut (dyn PartialReflect + 'static)>

Returns a mutable reference to the value of the field with index index as a &mut dyn Reflect.

fn field_len(&self) -> usize

Returns the number of fields in the tuple struct.

fn iter_fields(&self) -> TupleStructFieldIter<'_>

Returns an iterator over the values of the tuple struct’s fields.

fn to_dynamic_tuple_struct(&self) -> DynamicTupleStruct

Creates a new DynamicTupleStruct from this tuple struct.

fn get_represented_tuple_struct_info(&self) -> Option<&'static TupleStructInfo>

Will return None if TypeInfo is not available.

impl TypePath for Hovered

fn type_path() -> &'static str

Returns the fully qualified path of the underlying type.

fn short_type_path() -> &'static str

Returns a short, pretty-print enabled path to the type.

fn type_ident() -> Option<&'static str>

Returns the name of the type, or None if it is anonymous.

fn crate_name() -> Option<&'static str>

Returns the name of the crate the type is in, or None if it is anonymous.

fn module_path() -> Option<&'static str>

Returns the path to the module the type is in, or None if it is anonymous.

impl Typed for Hovered

fn type_info() -> &'static TypeInfo

Returns the compile-time info for the underlying type.

impl Copy for Hovered

impl Eq for Hovered

impl StructuralPartialEq for Hovered