Precisely scale Maya manipulators using addition instead of multiplication

maya_manipulator_size_hotkeys.py

'''
In Autodesk Maya, when you hit - and = to scale the manipulator gizmos, it *multiplies* the size.
So if it is small, it takes a long time to grow. And if it is big, and move in huge increments.
So I use addition and subtraction instead.
This gives you much more precise control.
Map the original ones to shift. _ and + to move in larger increments.

Just a tiny little tweak that helps me size it exactly how I want.
I use the radius of the rotation to measure pivot placement.
'''

# I map this to =
cmds.manipOptions(s=cmds.manipOptions(q=True, s=True)[0] + 0.3)

# I map this to -
cmds.manipOptions(s=cmds.manipOptions(q=True, s=True)[0] - 0.3)

# I also map the original IncreaseManipulatorSize to +
# And map DecreaseManipulatorSize to _