bootstack.App#

class bootstack.App(*, title=None, size=None, icon=None, theme=None, light_theme='bootstrap-light', dark_theme='bootstrap-dark', follow_system_appearance=False, available_themes=(), locale=None, localize_mode='auto', window_style='mica', macos_quit_behavior='native', remember_window_state=False, state_path=None, on_close=None, position=None, min_size=None, max_size=None, resizable=None, scaling=None, hdpi=True, undecorated=False, padding=None, gap=0, horizontal_items='center', vertical_items='top', grow_items=False, surface=None, **app_kwargs)#

Bases: AppConfigMixin, WindowControlsMixin, ChromeHostMixin, FlexContainer

The application window. Behaves as an implicit Column from the user’s perspective: accepts padding, gap, horizontal_items, vertical_items, and grow_items and applies them to its internal content frame.

Configuration is a single flat path: pass options as constructor kwargs and read or change them through matching app.* properties (e.g. app.theme, app.locale). Setting app.theme or app.locale takes effect live.

Parameters:

  • title (str | None) – Window title bar text and the app’s display name.

  • size (tuple[int, int] | None) – Initial window size as (width, height).

  • icon (str | Image | AppIcon | None) – Title-bar and taskbar icon — an icon file path, an Image handle, or an AppIcon. Defaults to the bootstack icon.

  • theme (str | None) – Theme name to apply on startup (e.g. 'bootstrap-dark').

  • light_theme (str) – Theme used for the light end of system-appearance tracking and toggle_theme.

  • dark_theme (str) – Theme used for the dark end of system-appearance tracking and toggle_theme.

  • follow_system_appearance (bool) – If True, switch between light_theme and dark_theme to match the OS (currently effective on macOS).

  • available_themes (Sequence[str]) – Theme names to expose to theme pickers. Empty means all registered themes.

  • locale (str | None) – Locale identifier (e.g. 'en_US', 'de_DE'). Auto-detected from the system when not given.

  • localize_mode (LocalizeMode) – Localization behavior.

  • window_style (WindowStyle | str | None) – Windows-only window effect, or None to disable.

  • macos_quit_behavior (Literal['native', 'classic']) – macOS close / Cmd+Q behavior. No-op on Win/Linux.

  • remember_window_state (bool) – If True, window geometry is saved on close and restored on next launch.

  • state_path (str | None) – Optional override for the persisted window-state file.

  • on_close (Callable[[], bool | None] | None) – Handler invoked when the user clicks the window’s close button. Return False to veto the close; return None or True to allow it. Not called by the programmatic close().

  • position (tuple[int, int] | None) – Initial window position as (x, y).

  • min_size (tuple[int, int] | None) – Minimum window size as (width, height).

  • max_size (tuple[int, int] | None) – Maximum window size as (width, height).

  • resizable (tuple[bool, bool] | None) – Whether the window can be resized as (width, height).

  • scaling (float | None) – Explicit UI scaling factor. When None, scaling is automatic.

  • hdpi (bool) – Enable high-DPI awareness for the application. Default True.

  • undecorated (bool) – Remove the OS title bar and border (borderless window). Ignored on macOS. The app gets a built-in draggable title bar with min/max/close so it stays movable and closeable; add your own with add_toolbar(show_window_controls=True) to take over the chrome.

  • padding (Padding | None) – Inner padding applied to the content frame.

  • gap (int) – Spacing between stacked children. Default 0.

  • horizontal_items (HAlign) – Horizontal alignment of children — 'left', 'center', 'right', or 'stretch' (fill the width). Default 'center'.

  • vertical_items (VArrange) – How children are arranged top to bottom — 'top', 'center', 'bottom', or a 'space-*' mode. Default 'top'.

  • grow_items (bool) – When True, children grow equally to fill the height. Default False.

  • surface (SurfaceToken | str | None) – Background surface for the content frame.

property dark_theme: str#

Theme used for the dark end of system-appearance / toggle_theme.

property follow_system_appearance: bool#

Whether the app tracks the OS light/dark appearance (macOS).

property light_theme: str#

Theme used for the light end of system-appearance / toggle_theme.

property locale: str | None#

The active locale (e.g. 'en_US'). Setting it switches locale live.

property locale_date_format: str | None#

Short date pattern for the active locale (e.g. 'M/d/yy'). Read-only.

property locale_decimal: str | None#

Decimal separator for the active locale (e.g. '.'). Read-only.

property locale_language: str | None#

Base language code derived from the locale (e.g. 'en'). Read-only.

property locale_thousands: str | None#

Thousands separator for the active locale (e.g. ','). Read-only.

property locale_time_format: str | None#

mm a. Read-only.

Type:

Short time pattern for the active locale, e.g. h

property remember_window_state: bool#

Whether window geometry is saved on close and restored on launch.

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 theme: str#

The active theme name. Setting it switches the theme live.

property title: str#

The window title bar text (also the app’s display name).

property window_style: WindowStyle | str | None#

Windows-only window effect, or None to disable.

classmethod from_store(store, **overrides)#

Construct an App from a persisted Store (or plain dict).

Reads configuration from store and applies it as constructor kwargs, tolerantly ignoring any keys that are not valid App configuration — so a settings file written by an older or newer version (with renamed or removed keys) still restores cleanly instead of raising. Explicit keyword overrides win over stored values.

Parameters:

  • store (Any) – A Store (anything with as_dict()) or a mapping of configuration values.

  • **overrides (Any) – Configuration kwargs that take precedence over the stored values.

Returns:

A new App configured from the store.

Return type:

App

Example

from bootstack.store import Store

store = Store("settings")
app = bs.App.from_store(store)
app.on_theme_change(lambda t: store.update(theme=t))
add_close_handler(handler)#

Register a veto-able close handler — an alias for on_close().

Parameters:

handler (Callable[[], bool | None]) – Called with no arguments on a close request. Return False to cancel the close.

add_toolbar(*, divider=False, use_macos_menus=True, **toolbar_kwargs)#

Append a Toolbar to the window’s top chrome stack and return it.

Toolbars stack full-width, top-to-bottom, in the order added — fill each with buttons, labels, widgets, and menus (toolbar.add_menu(...)). The returned Toolbar is a context manager, so the natural form reads:

with window.add_toolbar() as tb:
    tb.add_menu("File")
    tb.add_spacer()
    tb.add_theme_toggle()
Parameters:

  • divider (bool) – Draw a hairline beneath this toolbar (default False).

  • use_macos_menus (bool) – On macOS, bridge this toolbar’s menus to the native global menu bar (in-window dropdowns hide). Default True; set False to keep its menus in-window even on macOS. No effect on Windows/Linux.

  • **toolbar_kwargs (Any) – Forwarded to Toolbar — e.g. surface, density, button_variant, show_window_controls, draggable. Window chrome defaults surface='chrome' and density='compact' (a tight strip); pass density='default' for a roomier bar.

Returns:

The Toolbar for this layer.

Return type:

Any

capture(path, *, inset=0, settle=0.1)#

Save a picture of this widget to an image file.

Captures the area this widget occupies on screen — one widget, a whole window, or the entire application, depending on what you call it on. The file extension selects the format, so .png, .jpg, and .pdf all work.

The widget has to be visible. A capture reads pixels from the display, so the window is brought to the front first and a hidden or detached widget cannot be captured at all. Any always-on-top setting the window already had is left as it was found.

Pair it with a save dialog to let the user choose where it goes:

import bootstack as bs

def on_export():
    chosen = bs.ask_save_file(initial_file="dashboard.png")
    if chosen:
        app.capture(chosen)
Parameters:

  • path (str | Path) – Where to write the image. Missing parent folders are created, and the extension chooses the format.

  • inset (int) – Pixels to trim from every edge, zero or more. Use 2 on a whole window to drop the native border artifact.

  • settle (float) – Seconds to let the desktop finish repainting before the pixels are read. The default covers the common case of a dialog closing just beforehand. The interface pauses for this long, so a second click on the control that started the capture waits its turn rather than starting an overlapping one.

Returns:

The path that was written.

Raises:

BootstackError – If the widget is not visible on screen or has been scrolled out of view, if inset is negative, if no capture backend is available, or if the file cannot be written.

Return type:

Path

Added in version 0.3.0.

close()#

Close the window and exit its event loop.

For the application window this quits the loop started by run() — the natural action for a “Quit” command. It does not run the on_close veto handlers (those guard the user clicking the window’s close button), so a programmatic close() always proceeds.

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.

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.

It is meant for the framework’s own events — 'change', 'select', 'input' and the rest of the data-carrying names. A handler registered through on() or an on_<event>() shorthand receives what is emitted.

Names that map onto a native event instead ('click', 'focus', 'blur', 'submit', …) are a different matter: emitting one asks the toolkit to deliver a real input event, which carries no payload and can reach handlers the widget installed for its own use. Emitting those is not a way to notify listeners, and a listener bound through on() may not see it. Drive the widget through its properties and methods instead.

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. Pass the matching payload dataclass from bootstack.events — the same object an on_<event>() handler receives.

Example

from bootstack.events import ChangeEvent

field.emit("change", data=ChangeEvent(value=new_value))
guide_layout(child, **layout_kw)#

Place child into this container’s flow and snapshot its placement.

hide()#

Hide the window without destroying it.

The window is unmapped (and usually removed from the taskbar). Bring it back with show().

maximize()#

Maximize the window where the platform supports it.

minimize()#

Minimize the window to the taskbar or dock.

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_close(handler)#

Register a handler invoked when the user clicks the window’s close button.

Handlers run in registration order; return False from one to veto the close (the window stays open), or None/True to allow it. This guards the close-button gesture only — it is not run by the programmatic close().

Parameters:

handler (Callable[[], bool | None]) – Called with no arguments on a close request. Return False to cancel the close.

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_locale_change(handler=None)#

React to locale changes; the handler receives the new locale code.

Returns:

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

Return type:

Stream | Subscription

on_theme_change(handler=None)#

React to theme changes; the handler receives the new theme name.

Fired after the theme is fully rebuilt, so handlers can safely read new colors. Useful for persisting the choice, e.g. app.on_theme_change(lambda t: store.update(theme=t)).

Returns:

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

Return type:

Stream | Subscription

remove_close_handler(handler)#

Remove a close handler previously registered with on_close().

Parameters:

handler (Callable[[], bool | None]) – The same callable passed to on_close() or add_close_handler(). No-op if it was not registered.

run()#

Show the window and start the event loop.

set_fullscreen(value=True)#

Enter or leave fullscreen mode where supported.

Parameters:

value (bool) – True to enter fullscreen, False to exit. Default True.

set_topmost(value=True)#

Pin the window above all others, or release it.

Parameters:

value (bool) – True to keep the window above others, False to release. Default True.

show()#

Show the window — typically to reveal it again after hide().

For the application window, run() already shows it and starts the event loop; reach for show() to bring a hidden window back.