if possible use ink from theme as default colour
check_default_colour(default.colour, theme = NULL)A colour definition or NA
The value to be checked
The theme from where to fetch a replacement value when
default.colour is NULL.
The replacement value is fetched from the theme only if
'ggplot2' >= 4.0.0 and otherwise "black" is used. NA
values are passed through as they can be used to disable rendering
of grob elements.