Here is a full list of the default Shortcuts BPainter uses. 

  • BPainter Colorpicker -> Alt+Click or S
  • Eraser Switch -> E
  • Brush Size -> F
  • Brush Opacity -> Shift + F
  • Brush Hardness -> Alt+F
  • Texture Preview -> L
  • Disable Layermask -> Shift + Click on mask
  • Invert Layermask -> Ctrl + Click on mask