Autohotkey function that replicates Photoshop's spring loaded keys for any key. Makes a toggle temporary if key is held, or permanent if key is tapped.

SpringLoadedKey.ahk

; Replicates spring loaded key functionality for any key
SpringLoadedKey(key, timeHeld) ; parameters: hotkey that you want to send, timeout for the key to be considered held and not tapped
{
	send { %key% }				; send first hotkey on key down
	keywait, %A_ThisHotkey%			; wait for key up
	if (A_TimeSinceThisHotkey > timeHeld) 	; if key was down for more than the timeout value,
	{					; then on key up send the second hotkey to toggle it off,
		send { %key% }			; otherwise do nothing, making the toggle 'stick'
	}
}

; Call the function with something like
#IfWinActive ahk_exe Photoshop.exe
x::SpringLoadedKey("x", 500) ;spring loaded key for switching btw foreground and background colours
			; set the timeout value as required. I believe Photoshop's is 500 ms