Struct egui::Id [−][src]
egui tracks widgets frame-to-frame using Id
s.
For instance, if you start dragging a slider one frame, egui stores
the sliders Id
as the current active id so that next frame when
you move the mouse the same slider changes, even if the mouse has
moved outside the slider.
For some widgets Id
s are also used to persist some state about the
widgets, such as Window position or wether not a collapsing header region is open.
This implies that the Id
s must be unique.
For simple things like sliders and buttons that don’t have any memory and doesn’t move we can use the location of the widget as a source of identity. For instance, a slider only needs a unique and persistent ID while you are dragging the slider. As long as it is still while moving, that is fine.
For things that need to persist state even after moving (windows, collapsing headers) the location of the widgets is obviously not good enough. For instance, a collapsing region needs to remember wether or not it is open even if the layout next frame is different and the collapsing is not lower down on the screen.
Then there are widgets that need no identifiers at all, like labels, because they have no state nor are interacted with.
Implementations
impl Id
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pub fn new(source: impl Hash) -> Id
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Generate a new Id
by hashing some source (e.g. a string or integer).
pub fn with(self, child: impl Hash) -> Id
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Generate a new Id
by hashing the parent Id
and the given argument.
Trait Implementations
impl Clone for Id
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impl Copy for Id
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impl Debug for Id
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impl Eq for Id
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impl Hash for Id
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fn hash<__H: Hasher>(&self, state: &mut __H)
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pub fn hash_slice<H>(data: &[Self], state: &mut H) where
H: Hasher,
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H: Hasher,
impl PartialEq<Id> for Id
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impl StructuralEq for Id
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impl StructuralPartialEq for Id
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Auto Trait Implementations
Blanket Implementations
impl<T> Any for T where
T: 'static + ?Sized,
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T: 'static + ?Sized,
impl<T> Borrow<T> for T where
T: ?Sized,
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T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
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T: ?Sized,
pub fn borrow_mut(&mut self) -> &mut T
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impl<T> CallHasher for T where
T: Hash + ?Sized,
T: Hash + ?Sized,
pub default fn get_hash<H, B>(value: &H, build_hasher: &B) -> u64 where
B: BuildHasher,
H: Hash + ?Sized,
B: BuildHasher,
H: Hash + ?Sized,
impl<T> From<T> for T
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impl<T, U> Into<U> for T where
U: From<T>,
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U: From<T>,
impl<T> ToOwned for T where
T: Clone,
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T: Clone,
type Owned = T
The resulting type after obtaining ownership.
pub fn to_owned(&self) -> T
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pub fn clone_into(&self, target: &mut T)
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impl<T, U> TryFrom<U> for T where
U: Into<T>,
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U: Into<T>,
type Error = Infallible
The type returned in the event of a conversion error.
pub fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>
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impl<T, U> TryInto<U> for T where
U: TryFrom<T>,
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U: TryFrom<T>,