Struct Label 

pub struct Label { /* private fields */ }

A run of text drawn in a content colour, aligned inside its bounds.

Not interactive and not focusable, so a label inside a button never intercepts the click.

Implementations

impl Label

pub fn new(text: impl Into<String>) -> Self

A label in Role::BaseContent, left-aligned and vertically centred, in the built-in font at 16 px.

pub fn with_role(self, role: Role) -> Self

Sets the colour role. Pass a *Content role, or a surface role to draw the label in that colour rather than on it.

pub fn with_align(self, horizontal: Align, vertical: Align) -> Self

Sets horizontal and vertical alignment.

pub fn with_style(self, style: TextStyle) -> Self

Sets the font and size.

pub fn with_size(self, size_px: u16) -> Self

Sets the size, keeping the font.

pub const fn style(&self) -> TextStyle

The font and size this label draws in.

pub fn text(&self) -> &str

The current text.

pub fn set_text(&mut self, text: impl Into<String>)

Replaces the text.

Reach this through Ui::widget_mut, which marks the node dirty on the way in.

pub fn set_style(&mut self, style: TextStyle)

Replaces the font and size.

For an application that registers a font after building its tree, which is the ordinary case: the tree has to exist before anyone knows whether the font file was there.

pub fn set_role(&mut self, role: Role)

Replaces the colour role.

pub fn update(&mut self, text: &str) -> bool

Replaces the text only if it differs, reporting whether it changed.

For the common case of writing a reading into a label every tick: an unchanged value should not cost a repaint, and widget_mut cannot know that on its own.

Trait Implementations

impl Clone for Label

fn clone(&self) -> Label

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Label

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

Formats the value using the given formatter.

impl Describe for Label

const KIND: &'static str = "label"

The name a form file uses for this widget. Kebab-case.

const DOC: &'static str = "Text that is read and not touched."

One line saying what this widget is, for somebody choosing one.

const GROUP: Group = Group::Display

Which shelf of the catalogue this belongs on.

const ICON: &'static Icon

The widget’s glyph: a small portrait of the thing, for a palette to draw beside — or instead of — its name.

const PROPERTIES: &'static [Property]

Every property, in the order an inspector should show them.

fn get(&self, name: &str) -> Option<Value>

The current value.

fn apply(&mut self, name: &str, value: Value) -> Result<(), Mismatch>

Applies a value, reporting only what went wrong.

fn set(&mut self, name: &str, value: Value) -> Result<(), PropertyError>

Applies a value, reporting what went wrong and where.

impl<M: 'static> Widget<M> for Label

fn describe(&self) -> Option<&dyn DynDescribe>

This widget’s property description, if it has one.

fn describe_mut(&mut self) -> Option<&mut dyn DynDescribe>

The mutable half of describe.

fn measure(&self, ctx: &mut MeasureCtx<'_>, _offered: Offer) -> Measured

How big this widget would like to be, given what the caller can promise.

fn paint(&self, ctx: &mut PaintCtx<'_>, canvas: &mut Pen<'_>)

Draws into canvas, which is already clipped to this widget’s bounds intersected with the damage region being repainted.

fn on_event(&mut self, event: &Event<'_>, ctx: &mut EventCtx<'_, M>) -> Handled

Reacts to an event routed to this widget.

fn accepts_pointer(&self) -> bool

Returns true if the pointer can hit this widget.

fn focusable(&self) -> bool

Returns true if this widget can take keyboard focus.

fn preserves_focus(&self) -> bool

Returns true if a press on this widget should leave focus exactly where it is.

fn animate(&mut self, now_ms: u64) -> Animation

Advances time-based state. Called only while this widget has asked to animate — see EventCtx::request_animation — and stops being called the moment it answers Wake::Never.

fn snap(&mut self, now_ms: u64) -> Animation

Lands whatever is in flight at its end state, without animating it.