Re: [Ayatana] Thoughts on Unity design

[David Regev <david.regev@xxxxxxxxx>]

The equation doesn’t break down here because you’re not supposed to put in ∞. Although the edge may theoretically be infinitely long, it’s not in practice. Any human being aiming at the edge will stop within a certain distance past the edge. That means that, effectively, W is a certain fixed quantity, which can be determined through testing and seeing how far users actually travel past the edge. Jef Raskin, for example, found that W was 50 mm for the Macintosh. Using these methods, Fitts’ Law will get you more accurate results. You can also figure out how great D must be for global menus not to be faster any more (hint: probably much larger than your typical large monitor).
 

On Sun, May 22, 2011 at 16:53, Ed Lin <edlin280@xxxxxxxxx> wrote:

I'd also argue that while mathematically sound (at first glance) literally putting in infinity doesn't give you a realistic result, think divided by zero which can break an otherwise perfectly usable formula. Put in a ridiculously large "D" and with infinitive "W" you'd get exactly the same result (you'd calculate with zero) which doesn't take in account b, the inherent speed of the pointer. Clearly the law fails here. Just see the derivation: natural number =∞/2 ??  Someone with a bit more math background, please chime in.