pub struct LensWrap<T, U, L, W> { /* private fields */ }
Expand description
A wrapper for its widget subtree to have access to a part of its parent’s data.
Every widget in Druid is instantiated with access to data of some
type; the root widget has access to the entire application data.
Often, a part of the widget hierarchy is only concerned with a part
of that data. The LensWrap
widget is a way to “focus” the data
reference down, for the subtree. One advantage is performance;
data changes that don’t intersect the scope of the lens aren’t
propagated.
Another advantage is generality and reuse. If a widget (or tree of widgets) is designed to work with some chunk of data, then with a lens that same code can easily be reused across all occurrences of that chunk within the application state.
This wrapper takes a Lens
as an argument, which is a specification
of a struct field, or some other way of narrowing the scope.
Implementations§
Trait Implementations§
§impl<T, U, L, W> Widget<T> for LensWrap<T, U, L, W>where
T: Data,
U: Data,
L: Lens<T, U>,
W: Widget<U>,
impl<T, U, L, W> Widget<T> for LensWrap<T, U, L, W>where T: Data, U: Data, L: Lens<T, U>, W: Widget<U>,
§fn event(
&mut self,
ctx: &mut EventCtx<'_, '_>,
event: &Event,
data: &mut T,
env: &Env
)
fn event( &mut self, ctx: &mut EventCtx<'_, '_>, event: &Event, data: &mut T, env: &Env )
§fn lifecycle(
&mut self,
ctx: &mut LifeCycleCtx<'_, '_>,
event: &LifeCycle,
data: &T,
env: &Env
)
fn lifecycle( &mut self, ctx: &mut LifeCycleCtx<'_, '_>, event: &LifeCycle, data: &T, env: &Env )
§fn layout(
&mut self,
ctx: &mut LayoutCtx<'_, '_>,
bc: &BoxConstraints,
data: &T,
env: &Env
) -> Size
fn layout( &mut self, ctx: &mut LayoutCtx<'_, '_>, bc: &BoxConstraints, data: &T, env: &Env ) -> Size
§fn paint(&mut self, ctx: &mut PaintCtx<'_, '_, '_>, data: &T, env: &Env)
fn paint(&mut self, ctx: &mut PaintCtx<'_, '_, '_>, data: &T, env: &Env)
§fn compute_max_intrinsic(
&mut self,
axis: Axis,
ctx: &mut LayoutCtx<'_, '_>,
bc: &BoxConstraints,
data: &T,
env: &Env
) -> f64
fn compute_max_intrinsic( &mut self, axis: Axis, ctx: &mut LayoutCtx<'_, '_>, bc: &BoxConstraints, data: &T, env: &Env ) -> f64
§impl<T, U, L, W> WidgetWrapper for LensWrap<T, U, L, W>
impl<T, U, L, W> WidgetWrapper for LensWrap<T, U, L, W>
§type Wrapped = W
type Wrapped = W
Widget<impl Data>
(if existential bounds were supported).
Any other scheme leads to T
being unconstrained in unification at some point§fn wrapped(&self) -> &<LensWrap<T, U, L, W> as WidgetWrapper>::Wrapped
fn wrapped(&self) -> &<LensWrap<T, U, L, W> as WidgetWrapper>::Wrapped
§fn wrapped_mut(
&mut self
) -> &mut <LensWrap<T, U, L, W> as WidgetWrapper>::Wrapped
fn wrapped_mut( &mut self ) -> &mut <LensWrap<T, U, L, W> as WidgetWrapper>::Wrapped
Auto Trait Implementations§
impl<T, U, L, W> RefUnwindSafe for LensWrap<T, U, L, W>where L: RefUnwindSafe, T: RefUnwindSafe, U: RefUnwindSafe, W: RefUnwindSafe,
impl<T, U, L, W> Send for LensWrap<T, U, L, W>where L: Send, T: Send, U: Send, W: Send,
impl<T, U, L, W> Sync for LensWrap<T, U, L, W>where L: Sync, T: Sync, U: Sync, W: Sync,
impl<T, U, L, W> Unpin for LensWrap<T, U, L, W>where L: Unpin, T: Unpin, U: Unpin, W: Unpin,
impl<T, U, L, W> UnwindSafe for LensWrap<T, U, L, W>where L: UnwindSafe, T: UnwindSafe, U: UnwindSafe, W: UnwindSafe,
Blanket Implementations§
§impl<T> Instrument for T
impl<T> Instrument for T
§fn instrument(self, span: Span) -> Instrumented<Self> ⓘ
fn instrument(self, span: Span) -> Instrumented<Self> ⓘ
§impl<T> Pointable for T
impl<T> Pointable for T
§impl<T> RoundFrom<T> for T
impl<T> RoundFrom<T> for T
§fn round_from(x: T) -> T
fn round_from(x: T) -> T
§impl<T, U> RoundInto<U> for Twhere
U: RoundFrom<T>,
impl<T, U> RoundInto<U> for Twhere U: RoundFrom<T>,
§fn round_into(self) -> U
fn round_into(self) -> U
§impl<T, W> TestWidgetExt<T> for Wwhere
T: Data,
W: Widget<T> + 'static,
impl<T, W> TestWidgetExt<T> for Wwhere T: Data, W: Widget<T> + 'static,
§impl<T, W> WidgetExt<T> for Wwhere
T: Data,
W: Widget<T> + 'static,
impl<T, W> WidgetExt<T> for Wwhere T: Data, W: Widget<T> + 'static,
§fn align_left(self) -> Align<T>
fn align_left(self) -> Align<T>
Align
widget, configured to align left.§fn align_right(self) -> Align<T>
fn align_right(self) -> Align<T>
Align
widget, configured to align right.§fn align_vertical(self, align: UnitPoint) -> Align<T>
fn align_vertical(self, align: UnitPoint) -> Align<T>
Align
widget, configured to align vertically.§fn align_horizontal(self, align: UnitPoint) -> Align<T>
fn align_horizontal(self, align: UnitPoint) -> Align<T>
Align
widget, configured to align horizontally.§fn fix_width(self, width: impl Into<KeyOrValue<f64>>) -> SizedBox<T>
fn fix_width(self, width: impl Into<KeyOrValue<f64>>) -> SizedBox<T>
SizedBox
with an explicit width.§fn fix_height(self, height: impl Into<KeyOrValue<f64>>) -> SizedBox<T>
fn fix_height(self, height: impl Into<KeyOrValue<f64>>) -> SizedBox<T>
SizedBox
with an explicit height.§fn fix_size(
self,
width: impl Into<KeyOrValue<f64>>,
height: impl Into<KeyOrValue<f64>>
) -> SizedBox<T>
fn fix_size( self, width: impl Into<KeyOrValue<f64>>, height: impl Into<KeyOrValue<f64>> ) -> SizedBox<T>
SizedBox
with an explicit width and height§fn expand_width(self) -> SizedBox<T>
fn expand_width(self) -> SizedBox<T>
§fn expand_height(self) -> SizedBox<T>
fn expand_height(self) -> SizedBox<T>
§fn background(self, brush: impl Into<BackgroundBrush<T>>) -> Container<T>
fn background(self, brush: impl Into<BackgroundBrush<T>>) -> Container<T>
§fn foreground(self, brush: impl Into<BackgroundBrush<T>>) -> Container<T>
fn foreground(self, brush: impl Into<BackgroundBrush<T>>) -> Container<T>
§fn border(
self,
color: impl Into<KeyOrValue<Color>>,
width: impl Into<KeyOrValue<f64>>
) -> Container<T>
fn border( self, color: impl Into<KeyOrValue<Color>>, width: impl Into<KeyOrValue<f64>> ) -> Container<T>
§fn controller<C>(self, controller: C) -> ControllerHost<Self, C>where
C: Controller<T, Self>,
fn controller<C>(self, controller: C) -> ControllerHost<Self, C>where C: Controller<T, Self>,
Controller
.§fn on_added(
self,
f: impl Fn(&mut Self, &mut LifeCycleCtx<'_, '_>, &T, &Env) + 'static
) -> ControllerHost<Self, Added<T, Self>>
fn on_added( self, f: impl Fn(&mut Self, &mut LifeCycleCtx<'_, '_>, &T, &Env) + 'static ) -> ControllerHost<Self, Added<T, Self>>
§fn on_click(
self,
f: impl Fn(&mut EventCtx<'_, '_>, &mut T, &Env) + 'static
) -> ControllerHost<Self, Click<T>>
fn on_click( self, f: impl Fn(&mut EventCtx<'_, '_>, &mut T, &Env) + 'static ) -> ControllerHost<Self, Click<T>>
§fn debug_paint_layout(self) -> EnvScope<T, Self>
fn debug_paint_layout(self) -> EnvScope<T, Self>
layout
Rect
s of this widget and its children.§fn debug_widget_id(self) -> EnvScope<T, Self>
fn debug_widget_id(self) -> EnvScope<T, Self>
WidgetId
s for this widget and its children, when hot. Read more§fn debug_invalidation(self) -> DebugInvalidation<T, Self>
fn debug_invalidation(self) -> DebugInvalidation<T, Self>
§fn debug_widget(self) -> EnvScope<T, Self>
fn debug_widget(self) -> EnvScope<T, Self>
DEBUG_WIDGET
env variable for this widget (and its descendants). Read more§fn with_id(self, id: WidgetId) -> IdentityWrapper<Self>
fn with_id(self, id: WidgetId) -> IdentityWrapper<Self>
§fn disabled_if(
self,
disabled_if: impl Fn(&T, &Env) -> bool + 'static
) -> DisabledIf<T, Self>
fn disabled_if( self, disabled_if: impl Fn(&T, &Env) -> bool + 'static ) -> DisabledIf<T, Self>
DisabledIf
widget. Read more