Struct iced_core::Element

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pub struct Element<'a, Message, Theme, Renderer> { /* private fields */ }
Expand description

A generic Widget.

It is useful to build composable user interfaces that do not leak implementation details in their view logic.

If you have a built-in widget, you should be able to use Into<Element> to turn it into an Element.

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impl<'a, Message, Theme, Renderer> Element<'a, Message, Theme, Renderer>

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pub fn new(widget: impl Widget<Message, Theme, Renderer> + 'a) -> Self
where Renderer: Renderer,

Creates a new Element containing the given Widget.

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pub fn as_widget(&self) -> &dyn Widget<Message, Theme, Renderer>

Returns a reference to the Widget of the Element,

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pub fn as_widget_mut(&mut self) -> &mut dyn Widget<Message, Theme, Renderer>

Returns a mutable reference to the Widget of the Element,

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pub fn map<B>( self, f: impl Fn(Message) -> B + 'a, ) -> Element<'a, B, Theme, Renderer>
where Message: 'a, Theme: 'a, Renderer: Renderer + 'a, B: 'a,

Applies a transformation to the produced message of the Element.

This method is useful when you want to decouple different parts of your UI and make them composable.

§Example

Imagine we want to use our counter. But instead of showing a single counter, we want to display many of them. We can reuse the Counter type as it is!

We use composition to model the state of our new application:

use counter::Counter;

struct ManyCounters {
    counters: Vec<Counter>,
}

We can store the state of multiple counters now. However, the messages we implemented before describe the user interactions of a single counter. Right now, we need to also identify which counter is receiving user interactions. Can we use composition again? Yes.

#[derive(Debug, Clone, Copy)]
pub enum Message {
    Counter(usize, counter::Message)
}

We compose the previous messages with the index of the counter producing them. Let’s implement our view logic now:

use counter::Counter;

use iced::widget::row;
use iced::Element;

struct ManyCounters {
    counters: Vec<Counter>,
}

#[derive(Debug, Clone, Copy)]
pub enum Message {
    Counter(usize, counter::Message),
}

impl ManyCounters {
    pub fn view(&self) -> Element<Message> {
        // We can quickly populate a `row` by mapping our counters
        row(
            self.counters
                .iter()
                .map(Counter::view)
                .enumerate()
                .map(|(index, counter)| {
                    // Here we turn our `Element<counter::Message>` into
                    // an `Element<Message>` by combining the `index` and the
                    // message of the `element`.
                    counter.map(move |message| Message::Counter(index, message))
                }),
        )
        .into()
    }
}

Finally, our update logic is pretty straightforward: simple delegation.

impl ManyCounters {
    pub fn update(&mut self, message: Message) {
        match message {
            Message::Counter(index, counter_msg) => {
                if let Some(counter) = self.counters.get_mut(index) {
                    counter.update(counter_msg);
                }
            }
        }
    }
}
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pub fn explain<C: Into<Color>>( self, color: C, ) -> Element<'a, Message, Theme, Renderer>
where Message: 'a, Theme: 'a, Renderer: Renderer + 'a,

Marks the Element as to-be-explained.

The Renderer will explain the layout of the Element graphically. This can be very useful for debugging your layout!

Trait Implementations§

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impl<'a, Message, Theme, Renderer> Borrow<dyn Widget<Message, Theme, Renderer> + 'a> for &Element<'a, Message, Theme, Renderer>

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fn borrow(&self) -> &(dyn Widget<Message, Theme, Renderer> + 'a)

Immutably borrows from an owned value. Read more
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impl<'a, Message, Theme, Renderer> Borrow<dyn Widget<Message, Theme, Renderer> + 'a> for Element<'a, Message, Theme, Renderer>

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fn borrow(&self) -> &(dyn Widget<Message, Theme, Renderer> + 'a)

Immutably borrows from an owned value. Read more
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impl<'a, Message, Theme, Renderer> From<&'a str> for Element<'a, Message, Theme, Renderer>
where Theme: Catalog + 'a, Renderer: Renderer + 'a,

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fn from(content: &'a str) -> Self

Converts to this type from the input type.
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impl<'a, Message, Theme, Renderer> From<Text<'a, Theme, Renderer>> for Element<'a, Message, Theme, Renderer>
where Theme: Catalog + 'a, Renderer: Renderer + 'a,

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fn from( text: Text<'a, Theme, Renderer>, ) -> Element<'a, Message, Theme, Renderer>

Converts to this type from the input type.

Auto Trait Implementations§

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impl<'a, Message, Theme, Renderer> Freeze for Element<'a, Message, Theme, Renderer>

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impl<'a, Message, Theme, Renderer> !RefUnwindSafe for Element<'a, Message, Theme, Renderer>

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impl<'a, Message, Theme, Renderer> !Send for Element<'a, Message, Theme, Renderer>

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impl<'a, Message, Theme, Renderer> !Sync for Element<'a, Message, Theme, Renderer>

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impl<'a, Message, Theme, Renderer> Unpin for Element<'a, Message, Theme, Renderer>

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impl<'a, Message, Theme, Renderer> !UnwindSafe for Element<'a, Message, Theme, Renderer>

Blanket Implementations§

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impl<S, D, Swp, Dwp, T> AdaptInto<D, Swp, Dwp, T> for S
where T: Real + Zero + Arithmetics + Clone, Swp: WhitePoint<T>, Dwp: WhitePoint<T>, D: AdaptFrom<S, Swp, Dwp, T>,

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fn adapt_into_using<M>(self, method: M) -> D
where M: TransformMatrix<T>,

Convert the source color to the destination color using the specified method.
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fn adapt_into(self) -> D

Convert the source color to the destination color using the bradford method by default.
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impl<T> Any for T
where T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T, C> ArraysFrom<C> for T
where C: IntoArrays<T>,

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fn arrays_from(colors: C) -> T

Cast a collection of colors into a collection of arrays.
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impl<T, C> ArraysInto<C> for T
where C: FromArrays<T>,

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fn arrays_into(self) -> C

Cast this collection of arrays into a collection of colors.
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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
where T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<WpParam, T, U> Cam16IntoUnclamped<WpParam, T> for U
where T: FromCam16Unclamped<WpParam, U>,

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type Scalar = <T as FromCam16Unclamped<WpParam, U>>::Scalar

The number type that’s used in parameters when converting.
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fn cam16_into_unclamped( self, parameters: BakedParameters<WpParam, <U as Cam16IntoUnclamped<WpParam, T>>::Scalar>, ) -> T

Converts self into C, using the provided parameters.
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impl<T, C> ComponentsFrom<C> for T
where C: IntoComponents<T>,

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fn components_from(colors: C) -> T

Cast a collection of colors into a collection of color components.
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T> FromAngle<T> for T

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fn from_angle(angle: T) -> T

Performs a conversion from angle.
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impl<T, U> FromStimulus<U> for T
where U: IntoStimulus<T>,

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fn from_stimulus(other: U) -> T

Converts other into Self, while performing the appropriate scaling, rounding and clamping.
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impl<T> Instrument for T

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fn instrument(self, span: Span) -> Instrumented<Self>

Instruments this type with the provided [Span], returning an Instrumented wrapper. Read more
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fn in_current_span(self) -> Instrumented<Self>

Instruments this type with the current Span, returning an Instrumented wrapper. Read more
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impl<T, U> Into<U> for T
where U: From<T>,

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T, U> IntoAngle<U> for T
where U: FromAngle<T>,

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fn into_angle(self) -> U

Performs a conversion into T.
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impl<WpParam, T, U> IntoCam16Unclamped<WpParam, T> for U
where T: Cam16FromUnclamped<WpParam, U>,

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type Scalar = <T as Cam16FromUnclamped<WpParam, U>>::Scalar

The number type that’s used in parameters when converting.
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fn into_cam16_unclamped( self, parameters: BakedParameters<WpParam, <U as IntoCam16Unclamped<WpParam, T>>::Scalar>, ) -> T

Converts self into C, using the provided parameters.
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impl<T, U> IntoColor<U> for T
where U: FromColor<T>,

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fn into_color(self) -> U

Convert into T with values clamped to the color defined bounds Read more
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impl<T, U> IntoColorUnclamped<U> for T
where U: FromColorUnclamped<T>,

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fn into_color_unclamped(self) -> U

Convert into T. The resulting color might be invalid in its color space Read more
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impl<T> IntoStimulus<T> for T

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fn into_stimulus(self) -> T

Converts self into T, while performing the appropriate scaling, rounding and clamping.
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impl<T> Same for T

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type Output = T

Should always be Self
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impl<T, C> TryComponentsInto<C> for T
where C: TryFromComponents<T>,

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type Error = <C as TryFromComponents<T>>::Error

The error for when try_into_colors fails to cast.
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fn try_components_into(self) -> Result<C, <T as TryComponentsInto<C>>::Error>

Try to cast this collection of color components into a collection of colors. Read more
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impl<T, U> TryFrom<U> for T
where U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.
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impl<T, U> TryIntoColor<U> for T
where U: TryFromColor<T>,

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fn try_into_color(self) -> Result<U, OutOfBounds<U>>

Convert into T, returning ok if the color is inside of its defined range, otherwise an OutOfBounds error is returned which contains the unclamped color. Read more
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impl<C, U> UintsFrom<C> for U
where C: IntoUints<U>,

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fn uints_from(colors: C) -> U

Cast a collection of colors into a collection of unsigned integers.
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impl<C, U> UintsInto<C> for U
where C: FromUints<U>,

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fn uints_into(self) -> C

Cast this collection of unsigned integers into a collection of colors.
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impl<V, T> VZip<V> for T
where V: MultiLane<T>,

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fn vzip(self) -> V

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impl<T> WithSubscriber for T

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fn with_subscriber<S>(self, subscriber: S) -> WithDispatch<Self>
where S: Into<Dispatch>,

Attaches the provided Subscriber to this type, returning a [WithDispatch] wrapper. Read more
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fn with_current_subscriber(self) -> WithDispatch<Self>

Attaches the current default Subscriber to this type, returning a [WithDispatch] wrapper. Read more