Active layers
Layer order (drawn bottom → top):
Where does aes() live?
aes() tells ggplot which data columns control what you see (x-axis, y-axis, color…)
Color
Color which geoms?
Transparency (alpha)
Custom color palette
Adds scale_fill_manual() for violin and/or scale_color_manual() for points, depending on which geoms are active.
Appearance
Pre-built themes
Customize with theme()
Stack a theme() call on top of any pre-built theme, or use it alone to build your own theme from scratch.
Gridlines
Tick marks
Axis label text
Axis titles