Show a splash screen#

A splash screen is a borderless window shown while an app gets ready, replaced by the real window once the work is done. This recipe builds one that reports its progress and then hands off to the main window.

Hide the main window first#

The application root exists from the moment you create App, so the order is: create the root, hide it, show the splash, then bring the root back when the work is finished.

import ttkbootstrap as ttk

app = ttk.App(theme="bootstrap-light", size=(600, 400), title="Contact Book")
app.withdraw()

withdraw takes the window off the screen without destroying it — deiconify puts it back later. Build the main window’s widgets now, while it is hidden; that is usually the slow part you want the splash to cover.

Build the splash#

The splash is a Toplevel. Two options strip the window chrome, and you want both — each covers different platforms:

splash = ttk.Toplevel(
    window_type="splash",
    override_redirect=True,
    topmost=True,
    size=(360, 200),
)

panel = ttk.Frame(splash, bootstyle="primary").pack(fill="both", expand=True)
ttk.Label(panel, text="Contact Book", bootstyle="@primary",
          font="-size 18 -weight bold").pack(pady=(50, 4))
status = ttk.Label(panel, text="Starting…", bootstyle="@primary")
status.pack()

splash.place_window_center()

topmost keeps it above other windows, and place_window_center puts it in the middle of the screen. A splash has no titlebar to drag, so centering it is not a nicety — it’s the only placement the user gets.

Option

What it does

window_type="splash"

Removes the chrome on Linux and macOS. On macOS it also gets the window a real system shadow and rounded corners. Ignored on Windows.

override_redirect=True

Removes the chrome on Windows and Linux. Ignored on macOS, where it breaks click handling.

Show it, then work#

mainloop is not running yet, so nothing you have built has been drawn. Call update to pump the event loop once and paint the splash:

app.update()

status.configure(text="Loading contacts…")
app.update()
load_contacts()

status.configure(text="Connecting…")
app.update()
connect()

Every time you change the status text, update again — otherwise the label holds its old text until the next time the event loop runs, which is after all your work has finished.

Hand off to the main window#

Destroy the splash, show the real window, and start the event loop:

splash.destroy()
app.deiconify()
app.mainloop()

Note

Sprinkling update through a slow startup keeps the splash painted, but the app is still frozen between calls — the splash won’t redraw if it’s dragged over, and a spinner won’t spin. If your startup is long enough to care, run the work on a thread and let the splash animate while it runs; see Run background work.

See also

Reference#

  • Toplevel — window_type, override_redirect, topmost, and place_window_center.

  • App — withdraw and deiconify.

  • Lifecycle — update, and what pumping the event loop by hand actually does.