Discrete scale constructorSource:
Discrete scale constructor
The names of the aesthetics that this scale works with.
The name of the scale that should be used for error messages associated with this scale.
A palette function that when called with a single integer argument (the number of levels in the scale) returns the values that they should take (e.g.,
The name of the scale. Used as the axis or legend title. If
waiver(), the default, the name of the scale is taken from the first mapping used for that aesthetic. If
NULL, the legend title will be omitted.
NULLfor no labels
waiver()for the default labels computed by the transformation object
A character vector giving labels (must be same length as
An expression vector (must be the same length as breaks). See ?plotmath for details.
A function that takes the breaks as input and returns labels as output. Also accepts rlang lambda function notation.
NULLto use the default scale values
A character vector that defines possible values of the scale and their order
A function that accepts the existing (automatic) values and returns new ones. Also accepts rlang lambda function notation.
For position scales, a vector of range expansion constants used to add some padding around the data to ensure that they are placed some distance away from the axes. Use the convenience function
expansion()to generate the values for the
expandargument. The defaults are to expand the scale by 5% on each side for continuous variables, and by 0.6 units on each side for discrete variables.
Unlike continuous scales, discrete scales can easily show missing values, and do so by default. If you want to remove missing values from a discrete scale, specify
na.translate = FALSE.
na.translate = TRUE, what aesthetic value should the missing values be displayed as? Does not apply to position scales where
NAis always placed at the far right.
Should unused factor levels be omitted from the scale? The default,
TRUE, uses the levels that appear in the data;
FALSEuses all the levels in the factor.
A function used to create a guide or its name. See
guides()for more information.
For position scales, The position of the axis.
rightfor y axes,
bottomfor x axes.
The super class to use for the constructed scale