Re:Apple Designs a Virtual Knob
by DonHopkins on Saturday October 11, 2025 @06:38PM
(#45553265)
>The ability to naturally gain precision the further out you drag is very handy and intuitive.
Pie menus, where the selection is based on the gesture direction, allow you to move further out (longer gesture) to get more "leverage" or precise control over the angle (either continuous angle, or the selected slice).
The angle selects a slice, but you can think of a knob as a pie menu with one slice (the whole pie) that also has a direction and a optional distance parameter.
But you can even use the distance to exaggerate the angular precision even more!
Here's a demo of a "Precision Pie Menu" I wrote in 1988 for NeWS in PostScript, which exaggerated that angular precision effect even more, once you pass a certain distance, allowing you to have extremely precise control over the angle.
>Demo of the precision pie menu. Research performed by Don Hopkins under the direction of Mark Weiser and Ben Shneiderman. Developed and demonstrated by Don Hopkins.
>Transcript:
This is a demonstration of the Precision
Pie Menu under the NeWS window system.
It's an experiment in exaggerating the
extra precision that you get with
distance.
As you move out further from
the menu center of a pie menu, normally
the further you go from the center the
more control you have over the angle.
But if you want to input an exact number
like an angle, you might want to get it
down to the a certain number, but you run
out of screen space before you get
enough leverage to change the number to
what you want.
Now what happens here is
that when you poke out,
it makes a flexible lever, that the
further out you go, the more flexible it
becomes, and you have much finer control
over the number.
So as I move around back
in and out, I'll poke it into a different
place and just come out further to get a
lot of leverage, and dial exactly the
number I want.
So here's what happens when you go
around to the other side:
"pop pop"!
And as you get
nearer it gets less and less
flexible.
Generally you'd kind of eyeball
it, and then get it exact like 93, well
there's 93 or 273, there's 273.
Pie menus, where the selection is based on the gesture direction, allow you to move further out (longer gesture) to get more "leverage" or precise control over the angle (either continuous angle, or the selected slice).
The angle selects a slice, but you can think of a knob as a pie menu with one slice (the whole pie) that also has a direction and a optional distance parameter.
But you can even use the distance to exaggerate the angular precision even more!
Here's a demo of a "Precision Pie Menu" I wrote in 1988 for NeWS in PostScript, which exaggerated that angular precision effect even more, once you pass a certain distance, allowing you to have extremely precise control over the angle.
https://www.youtube.com/watch?v=c0scs59va4c
>Demo of the precision pie menu. Research performed by Don Hopkins under the direction of Mark Weiser and Ben Shneiderman. Developed and demonstrated by Don Hopkins.
>Transcript:
This is a demonstration of the Precision Pie Menu under the NeWS window system.
It's an experiment in exaggerating the extra precision that you get with distance.
As you move out further from the menu center of a pie menu, normally the further you go from the center the more control you have over the angle.
But if you want to input an exact number like an angle, you might want to get it down to the a certain number, but you run out of screen space before you get enough leverage to change the number to what you want.
Now what happens here is that when you poke out, it makes a flexible lever, that the further out you go, the more flexible it becomes, and you have much finer control over the number.
So as I move around back in and out, I'll poke it into a different place and just come out further to get a lot of leverage, and dial exactly the number I want.
So here's what happens when you go around to the other side: "pop pop"!
And as you get nearer it gets less and less flexible.
Generally you'd kind of eyeball it, and then get it exact like 93, well there's 93 or 273, there's 273.