I do not know of a way. If you use a Wacon Tablet you may be able to set the Pen buttons to what you need.
If not on windows you can set pen's botton button to Alt+Right click and then all you need do is with the pen closte to the tablet drag up/down or left/right to change brush tip size or hardness. Easy and quick.
Use Adobe feedback site suggest that option should be added to windows Photoshop. Photoshop Family Customer Community
Thank you for the reply, Yea I just can't understand how they would have the shortcut on one platform and not on the other, makes no sense. it's a HUGE timesaving ease of use shortcut. It's slowed me down tremendously, not having it.
I really need to find some way to make it work like the mac, or I may have to switch back. This is kinda a dealbreaker since I spend 8 hours a day in PS working on images.
IMO if you are using a brush type tool 8 hours a day you should be using a pen not a mouse. A pen will cut your paint time way down. Adjusting the tip size and hardness will not be a problem with a wacom tablet or cintiq.
I do use a Intuos 4 Pro. I don't use the mouse, that'd be impossible.
The problem is still the same.
Trying to hold the pen slightly off the tablet while holding alt on keyboard and using the pen button is very clunky...
The way it works on Mac is ideal... I hold the keys on the keyboard and touch the pen down and drag left/right for brush size and up/down for hardness.... it's perfect.