Struct RadialProgress 

pub struct RadialProgress { /* private fields */ }

A determinate circular progress indicator, 0.0 to 1.0.

Not interactive, not focusable, not a tab stop. It reports; it does not take input. The value contract is Progress’s exactly — NaN draws an empty ring, out of range clamps, and update reports whether the value actually moved — because the number is done / total here too, and total is eventually zero.

RadialProgress::new(0.7).with_label("70 %");
RadialProgress::new(used / capacity).with_role(Role::Warning);

It is a circle, so it inscribes rather than fills

The ring takes min(width, height) / 2 as its radius and centres itself in the rectangle. A radial progress squashed into an ellipse is not a radial progress, and the alternative — demanding a square — would make every caller do this arithmetic instead.

It takes a label, and Progress deliberately does not

Not an inconsistency. A percentage drawn inside a bar sits on the fill at one end and on the track at the other, so it needs two colours in one string to stay readable; that is why Progress has no text.

A ring has an empty middle. The label sits on the panel behind the widget rather than on the ring, so it is one colour — the same arrangement Divider’s label already uses. The two-colour problem simply does not arise, which is the whole reason this is where the number goes.

The caller formats it. A widget that turned 0.7 into "70 %" would be choosing decimals and a locale on the caller’s behalf, and update plus set_label are two calls in the place that already knows both.

Implementations

impl RadialProgress

pub fn new(value: f32) -> Self

A ring at value, which is clamped — see RadialProgress::set_value.

pub fn with_label(self, label: impl Into<String>) -> Self

Puts text in the middle of the ring.

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

Sets the colour of the filled arc.

Warning or Error for a ring that means something is running out rather than something is being achieved.

pub fn with_thickness(self, thickness: i32) -> Self

Sets the ring’s thickness in pixels, instead of deriving it.

Clamped to the radius: a thickness at or past it fills to the centre, which is a pie chart rather than a ring and leaves no hole for a label.

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

Sets the label’s font and size.

pub const fn value(&self) -> f32

The current value, always in 0.0..=1.0.

pub fn set_value(&mut self, value: f32)

Sets the value, clamped into range, with NaN as zero.

The reasoning is Progress::set_value’s: a panic inside a paint loop on a kiosk is a black screen with no way to report itself, so a nonsense number draws an honest empty ring instead.

pub fn update(&mut self, value: f32) -> bool

Sets the value, reporting whether it actually changed.

A panel writes its readings every cycle whether or not they moved, and repainting for a value that did not change is how an idle device stops being idle.

pub fn label(&self) -> &str

The current label, empty if there is none.

pub fn set_label(&mut self, label: impl Into<String>)

Replaces the label.

pub fn update_label(&mut self, label: &str) -> bool

Replaces the label, reporting whether it actually changed.

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

Replaces the colour role.

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

Replaces the label’s font and size.

Trait Implementations

impl Clone for RadialProgress

fn clone(&self) -> RadialProgress

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for RadialProgress

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

Formats the value using the given formatter.

impl Default for RadialProgress

fn default() -> Self

Returns the “default value” for a type.

impl Describe for RadialProgress

const KIND: &'static str = "radial-progress"

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

const DOC: &'static str = "A ring that fills clockwise, with room for a number inside it."

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

const GROUP: Group = Group::Indicator

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 RadialProgress

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

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

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.