slider.knobSize < number>

The size of the knob. This automatically sets the width and height of the knob. The default value is 30.
译：旋钮的大小。这会自动设置旋钮的宽度和高度。默认值是“30”。

# Create a SliderComponent  
slider = new SliderComponent
slider.center()

# Change the size of the knob 
slider.knobSize = 40