how to create live-tracking button?

Hi,

Is there a way to override any form of button control or HIView so that I can do live tracking while the button is being pressed, but leave it up to the Toolbox to handle tracking and appearance of the button between pressed and non-pressed states?  My goal is a button that performs a periodic action for as long as it's pressed (think: "continuous zoom in").

The best I've come up with so far is to add a kEventControlClick handler to an image-based-button created by CreatePictureControl() or CreateBevelButtonControl().  I only get this event once per click (immediately on mousedown). From there I could enter my own stilldown loop using TrackMouseLocation, and do all of the mouse-tracking and button redrawing myself using HITheme API and HIViewDrawCGImage, while simulateously using a periodic timer to fire tracking events to my actual logic. This seems close to reimplementing a button's whole appearance and mouse-behavior logic from scratch: all the ControlRef is doing is defining the ControlBounds and sending me kEventControlClick. Am I missing something obvious, or is this as good as it gets?

Thanks,

Nick Jackiw

KCP Technologies