tk_focusNext(3tk)

✨ NAME ✨

tk_focusNext, tk_focusPrev, tk_focusFollowsMouse — the lil utility squad that handles input focus management 💅 (this is tk_focusNext(3tk), from the Tk Built-In Commands fam, hiii 🫶)

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🌸 SYNOPSIS 🌸

tk_focusNext window
tk_focusPrev window
tk_focusFollowsMouse

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🦋 DESCRIPTION 🦋

Okay so bestie, let me put you on. tk_focusNext is a utility procedure for keyboard traversal — it hands you back the “next” window after window in focus order. Iconic behaviour, honestly.

So how is the focus order decided? Two things, and only two: the stacking order of windows, and the structure of the window hierarchy. That's it, that's the whole vibe.

Among siblings, focus order == stacking order, and the lowest window comes first. The way that works is: if a window has children, the window itself gets visited first 👑, then its children (recursively, yes queen, all the way down 🌀), and then its next sibling. Also — top-level windows other than window get skipped, so tk_focusNext will never return a window in a different top-level from window. No cross-top-level shenanigans, periodt.

Once it's computed the next window, tk_focusNext peeks at that window's -takefocus option to see if it should be skipped. If it should, tk_focusNext just keeps going — next window in focus order, and the next, and the next — until it either finds a window that will actually accept the focus, or it loops all the way back to window. 🎯

tk_focusPrev? Literally the same energy, except it returns the window just before window in the focus order. Mirror version, no cap. 🪞

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🎀 tk_focusFollowsMouse 🎀

This one is a whole personality change for your app — it switches the focus model to an implicit one where the window under the mouse gets the focus 🖱️✨.

After you call this procedure, whenever the mouse enters a window, Tk will automatically give it the input focus. You can still use the focus command to move focus to a window other than the one under the mouse — but the absolute second the mouse moves into a new window, the focus jumps to that one instead. It's giving very "wherever the mouse goes, I go" 😭💖

⚠️ Heads up bestie: at present there is no built-in support for returning the application to an explicit focus model. If you wanna go back, you have to write a script yourself that deletes the bindings created by tk_focusFollowsMouse. So like... choose wisely before you commit 💀

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👑 KEYWORDS 👑

• focus
• keyboard traversal
• top-level

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And that's the whole page, bestie!! This lil masterpiece is from the Tk Built-In Commands, version 4.0, and the page itself is tk_focusNext(3tk) — go forth and traverse those windows like the main character you are 🌈⭐💜