How can I key brush size to one button?

[Viradical]

At the Revelations Workshop, I got a chance to interview some of my heroes like Android and Sparth. In their key configs, they had somehow keyed their current brush size to a single button, and all they had to do to change brush size was hold the button down and make a pen stroke one way or another.

I've looked through my Tablet properties, as well as the Photoshop and Painter help files trying to find a hot key, but come up empty.

I've been tracking how much of my workflow is spent going to the size shifter bar in both Photoshop and Painter, it will be a big help. I could set a couple buttons as [ and ] (incremental size increase), but then I have to take off another button function I rely on to make room.

So again: how do I key brush size to pen stroke?

Thanks in advance.

[ItsChoco]

It's likely they were using Painter which does have this option. Unfortunately, I do not believe such an option is available in Photoshop.

[JamesOutlaw3D]

I haven't seen that in Photoshop.
Just use your bracket keys to increase or decrease brush size.
[ to decrease.
] to increase.