bootstack.Gauge#

class bootstack.Gauge(value=0, *, min_value=0, max_value=100, subtitle=None, value_prefix=None, value_suffix=None, value_template='{:.0f}', size=200, thickness=10, variant='full', segment_width=0, interactive=False, step=1, show_text=True, accent=None, surface=None, parent=None, **kwargs)#

Bases: PublicWidgetBase

A circular gauge for displaying a value within a range.

Renders a circular arc gauge with an optional center text display. Supports full-circle and semicircle layouts, solid and segmented arcs, and an interactive drag mode for value input.

Parameters:

  • value (int | float) – Initial value. Defaults to 0.

  • min_value (int | float) – Minimum of the range. Defaults to 0.

  • max_value (int | float) – Maximum of the range. Defaults to 100.

  • subtitle (str | None) – Secondary label displayed below the value text.

  • value_prefix (str | None) – Text prepended to the displayed value (e.g. '$').

  • value_suffix (str | None) – Text appended to the displayed value (e.g. '%').

  • value_template (str) – Python format string applied to the value (e.g. '{:.0f}', '{:.1f}'). Pair with value_prefix/value_suffix for units. Default '{:.0f}' (integer display). For locale-aware formatting, format the value yourself and pass it via value=.

  • size (int) – Diameter of the gauge in pixels. Defaults to 200.

  • thickness (int) – Width of the arc stroke in pixels. Defaults to 10.

  • variant (Literal['full', 'semi']) – Shape variant. 'full' (default) draws a complete 360° ring; 'semi' draws a half-circle arc along the bottom.

  • segment_width (int) – Width of each dash segment for a dashed arc style. 0 (default) draws a solid arc.

  • interactive (bool) – If True, the user can click or drag the arc to change the value. Defaults to False.

  • step (int | float) – Value increment per drag step in interactive mode. Defaults to 1.

  • show_text (bool) – If False, hides the center value text. Defaults to True.

  • accent (AccentToken | str | None) – Color intent token for the arc. Defaults to the theme’s default color.

  • surface (SurfaceToken | str | None) – Surface token for the gauge background, so it matches the container it sits on (e.g. 'card' inside a Card). Defaults to the window background.

  • parent (Any) – Override the context-stack parent.

  • **kwargs (Any) – Layout placement options applied by the parent container — fill, expand, anchor, margin, row, column, sticky. See Layout & Spacing.

property is_attached: bool#

Whether the widget is currently placed in its layout.

True while the widget occupies space in its parent; False after detach (or before it has ever been placed). A detached widget keeps its state and can be returned to the layout with attach.

property max_value: int | float#

The high end of the range. Assigning to it rescales the gauge live.

property min_value: int | float#

The low end of the range. Assigning to it rescales the gauge live.

property schedule: Schedule#

Scheduler tied to this widget’s lifetime.

All jobs are automatically cancelled when the widget is destroyed. First access creates the Schedule instance; subsequent accesses return the same instance.

Usage:

self.schedule.delay(500, callback)
self.schedule.every(1000, tick)
job = self.schedule.idle(refresh)
job.cancel()
property subtitle: str#

The secondary label shown below the value text.

property value: int | float#

The current gauge value.

attach(**kwargs)#

Return a detached widget to its layout, optionally moving it.

With no arguments, restores the widget to exactly where detach took it from. Any layout kwargs accepted by the original placement (e.g. fill, expand, anchor, sticky, margin) override the stored options. For stacked widgets, index= sets the position among the currently attached siblings (or pass an explicit before=/after= sibling); without one, the snapshotted position is used.

Calling attach on a widget that is already attached moves it (the kwargs are re-applied). Fires on_attach.

Parameters:

**kwargs (Any) – Layout placement options to override for this placement.

Raises:

ParentResolutionError – If the widget was never placed in a layout.

destroy()#

Destroy the widget and release the resources it holds.

Removes the widget from its parent, destroys its children, and cancels any pending or repeating jobs on its schedule. After this the widget must not be used again. Destroying a container destroys everything inside it.

detach()#

Remove the widget from its layout without destroying it.

The widget stops occupying space but keeps its state, children, and event bindings, ready to be returned with attach. The current position is snapshotted so a plain attach() restores it exactly — for stacked siblings this is the index among the currently attached siblings, so detaching other siblings first shifts that index.

Calling detach on a widget that is already detached, or one that was never placed in a layout, does nothing. Fires on_detach.

emit(event, *, data=None)#

Fire a named event on this widget, as if it produced the event itself.

This is how a composite widget surfaces high-level activity to its listeners, and the generic counterpart to the on_*() shorthands for firing events that have no dedicated method.

Parameters:

  • event (str) – The event name, unprefixed — the same name you pass to on() or an on_<event>() shorthand (e.g. 'change', 'select').

  • data (Any) – The payload delivered to handlers. For a data-carrying event, pass the matching payload dataclass from bootstack.events — the same object an on_<event>() handler receives. Leave as None for native events (click, hover, focus, …), which carry no payload.

Example

widget.emit("change", data=bs.events.ChangeEvent(value=new_value))
get_clipboard()#

Return the current text contents of the system clipboard.

Returns:

The clipboard text, or an empty string when the clipboard is empty or holds non-text data.

Return type:

str

on(event, handler=None)#

Bind handler to event, or return a composable Stream.

With a handler — binds immediately and returns a Subscription:

sub = widget.on("change", handler)
sub.cancel()

Without a handler — returns a Stream for operator chaining. The Tk binding is created lazily when .listen() is called:

sub = widget.on("change").debounce(300).listen(handler)
sub.cancel()
Parameters:

  • event (str) – Event name (e.g. "change", "click").

  • handler (Callable[[Any], Any] | None) – Optional callback. If omitted, a Stream is returned.

Returns:

Subscription when a handler is provided; Stream otherwise.

Return type:

Stream | Subscription

on_attach(handler=None)#

Register a callback fired when the widget enters the layout.

Fires each time the widget becomes visible in its parent — on initial placement and on every attach. Pair it with on_detach to keep per-visibility resources (timers, observers) tied to the widget’s presence on screen. The handler receives a curated Event.

Parameters:

handler (Callable[[Event], Any] | None) – Called when the widget is attached. Omit to get a composable Stream.

Returns:

A cancellable Subscription when a handler is given, otherwise a Stream.

Return type:

Stream | Subscription

on_change() → Stream#
on_change(handler: Callable[[SliderEvent], Any]) → Subscription

Register a callback fired when the gauge value changes.

Parameters:

handler (Callable[[SliderEvent], Any] | None) – Called with a SliderEvent. Omit to get a composable Stream instead.

Returns:

A cancellable Subscription when a handler is given, otherwise a Stream.

Return type:

Stream | Subscription

on_destroy(handler=None)#

Register a callback fired when the widget is destroyed.

Fires once, as the widget is torn down — the place to release resources the widget owns that aren’t cleaned up automatically (file handles, observers, external subscriptions). The handler receives a curated Event.

Parameters:

handler (Callable[[Event], Any] | None) – Called as the widget is destroyed. Omit to get a composable Stream.

Returns:

A cancellable Subscription when a handler is given, otherwise a Stream.

Return type:

Stream | Subscription

on_detach(handler=None)#

Register a callback fired when the widget leaves the layout.

Fires each time the widget stops occupying space in its parent — on detach and when an ancestor hides it. Pair it with on_attach to release per-visibility resources. The handler receives a curated Event.

Parameters:

handler (Callable[[Event], Any] | None) – Called when the widget is detached. Omit to get a composable Stream.

Returns:

A cancellable Subscription when a handler is given, otherwise a Stream.

Return type:

Stream | Subscription

set_clipboard(text)#

Replace the system clipboard contents with text.

Parameters:

text (str) – The text to place on the clipboard.