Alpha-transparency scales are not tremendously useful, but can be a
convenient way to visually down-weight less important observations.
scale_alpha is an alias for
that is the most common use of alpha, and it saves a bit of typing.
scale_alpha(..., range = c(0.1, 1)) scale_alpha_continuous(..., range = c(0.1, 1)) scale_alpha_discrete(..., range = c(0.1, 1))
Output range of alpha values. Must lie between 0 and 1.
p + scale_alpha("cylinders")p + scale_alpha(range = c(0.4, 0.8))