bootstack.Label#

class bootstack.Label(text='', *, textsignal=None, value_format=None, image=None, icon=None, icon_only=False, icon_position='left', anchor=None, justify=None, padding=None, width=None, wrap_width=None, font=None, accent=None, variant=None, surface=None, localize=None, parent=None, **kwargs)#

Bases: IconProperty, ImageProperty, PublicWidgetBase

Static text display with optional icon, semantic styling, and font tokens.

The display text is the first positional argument. All options are keyword-only.

Parameters:

  • text (str) – Text to display.

  • textsignal (Signal | None) – Reactive Signal bound to the display text. Updates automatically when the signal changes. Combine with value_format= to format numeric or date values.

  • value_format (str | None) – Format applied to the textsignal value before display — a named preset (e.g. 'decimal', 'currency', 'shortDate') or a custom pattern (e.g. '#,##0'). Requires textsignal= and localization enabled. See format specs.

  • image (Any) – An Image handle (from bootstack.images) to display, for custom artwork rather than a Bootstrap Icon name. Also accepts a get_icon result. Use icon_position= to control placement relative to text.

  • icon (str | IconSpec | None) – Bootstrap Icons name (e.g. 'house', 'gear') — see the full catalog at https://icons.getbootstrap.com — or an IconSpec mapping ({'name', 'size', 'color'}) for control over size and color.

  • icon_only (bool) – If True, show only the icon. Auto-detected when text is empty and icon is provided.

  • icon_position (IconPosition) – Position of the icon or image relative to the text. Only relevant when an icon or image is shown alongside text. Default 'left'.

  • anchor (Anchor | None) – Content alignment within the label area. Default 'center'.

  • justify (Justify | None) – Multi-line text alignment.

  • padding (Padding | None) – Inner spacing around the text content.

  • width (int | None) – Width in character units.

  • wrap_width (int | None) – Maximum pixel width before text wraps. Set to enable multi-line wrapping.

  • font (str | None) – Semantic font token. Examples: 'body', 'heading-lg', 'heading-md[bold]', 'caption', 'code', 'body+2[italic]'.

  • accent (AccentToken | Literal['muted'] | str | None) – Semantic color applied to the text.

  • variant (VariantToken | str | None) – Style variant token.

  • surface (SurfaceToken | str | None) – Background surface context.

  • localize (bool | Literal['auto'] | None) – Whether the text is translated through the catalog — True, False, or 'auto' (translate when a translation is registered, otherwise show the literal). Defaults to the app’s localize_mode. Set False to keep a proper noun or identifier untranslated.

  • parent (Any) – Explicit parent widget. If omitted, the current context-stack container is used.

property icon: str | IconSpec | None#

The icon shown on the widget, or None if none is set.

A Bootstrap Icons name, or an IconSpec mapping ({'name', 'size', 'color'}) for control over size and color.

property image: Any#

The displayed image handle, or None.

Assigning an Image (from bootstack.images) updates the picture in place — no rebuild — which avoids the flicker of recreating the widget.

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 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 text: str#

The displayed text.

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_click() → Stream#
on_click(handler: Callable[[Event], Any]) → Subscription

Register a callback for click events on this label.

Called with no handler, returns a composable Stream. Called with a handler, binds it immediately and returns a Subscription. The handler receives the curated Event (pointer position, modifier keys).

Parameters:

handler (Callable[[Event], Any] | None) – Called with the click Event when the label is clicked.

Returns:

Subscription (with handler) or Stream (without handler).

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.