R/as-discretised-scale.R
, R/scale-unbinned.R
discretised_scale.Rd
This scale allows ggplot to understand data that has been discretised with
some procedure akin to cut
and access the underlying continuous values.
For a scale that does the opposite (take continuous data and treat them as
discrete) see ggplot2::binned_scale()
.
as.discretised_scale(scale_function)
scale_fill_discretised(
...,
low = "#132B43",
high = "#56B1F7",
space = "Lab",
na.value = "grey50",
guide = ggplot2::guide_colorsteps(even.steps = FALSE, show.limits = TRUE),
aesthetics = "fill"
)
scale_fill_divergent_discretised(
...,
low = scales::muted("blue"),
mid = "white",
high = scales::muted("red"),
midpoint = 0,
space = "Lab",
na.value = "grey50",
guide = ggplot2::guide_colorsteps(even.steps = FALSE, show.limits = TRUE)
)
discretised_scale(
aesthetics,
scale_name,
palette,
name = ggplot2::waiver(),
breaks = ggplot2::waiver(),
labels = ggplot2::waiver(),
limits = NULL,
trans = scales::identity_trans(),
na.value = NA,
drop = FALSE,
guide = ggplot2::guide_colorsteps(even.steps = FALSE),
position = "left",
rescaler = scales::rescale,
oob = scales::censor,
super = ScaleDiscretised
)
a scale function (e.g. scale_fill_divergent
)
Arguments passed on to continuous_scale
scale_name
The name of the scale that should be used for error messages associated with this scale.
palette
A palette function that when called with a numeric vector with
values between 0 and 1 returns the corresponding output values
(e.g., scales::pal_area()
).
breaks
One of:
NULL
for no breaks
waiver()
for the default breaks computed by the
transformation object
A numeric vector of positions
A function that takes the limits as input and returns breaks
as output (e.g., a function returned by scales::extended_breaks()
).
Note that for position scales, limits are provided after scale expansion.
Also accepts rlang lambda function notation.
minor_breaks
One of:
NULL
for no minor breaks
waiver()
for the default breaks (none for discrete, one minor break
between each major break for continuous)
A numeric vector of positions
A function that given the limits returns a vector of minor breaks. Also accepts rlang lambda function notation. When the function has two arguments, it will be given the limits and major break positions.
n.breaks
An integer guiding the number of major breaks. The algorithm
may choose a slightly different number to ensure nice break labels. Will
only have an effect if breaks = waiver()
. Use NULL
to use the default
number of breaks given by the transformation.
labels
One of:
NULL
for no labels
waiver()
for the default labels computed by the
transformation object
A character vector giving labels (must be same length as breaks
)
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.
limits
One of:
NULL
to use the default scale range
A numeric vector of length two providing limits of the scale.
Use NA
to refer to the existing minimum or maximum
A function that accepts the existing (automatic) limits and returns
new limits. Also accepts rlang lambda function
notation.
Note that setting limits on positional scales will remove data outside of the limits.
If the purpose is to zoom, use the limit argument in the coordinate system
(see coord_cartesian()
).
rescaler
A function used to scale the input values to the
range [0, 1]. This is always scales::rescale()
, except for
diverging and n colour gradients (i.e., scale_colour_gradient2()
,
scale_colour_gradientn()
). The rescaler
is ignored by position
scales, which always use scales::rescale()
. Also accepts rlang
lambda function notation.
oob
One of:
Function that handles limits outside of the scale limits (out of bounds). Also accepts rlang lambda function notation.
The default (scales::censor()
) replaces out of
bounds values with NA
.
scales::squish()
for squishing out of bounds values into range.
scales::squish_infinite()
for squishing infinite values into range.
trans
call
The call
used to construct the scale for reporting messages.
super
The super class to use for the constructed scale
Colours for low and high ends of the gradient.
colour space in which to calculate gradient. Must be "Lab" - other values are deprecated.
Colour to use for missing values
Type of legend. Use "colourbar"
for continuous
colour bar, or "legend"
for discrete colour legend.
Character string or vector of character strings listing the
name(s) of the aesthetic(s) that this scale works with. This can be useful, for
example, to apply colour settings to the colour
and fill
aesthetics at the
same time, via aesthetics = c("colour", "fill")
.
colour for mid point
The midpoint (in data value) of the diverging scale. Defaults to 0.
The name of the scale that should be used for error messages associated with this scale.
A palette function that when called with a numeric vector with
values between 0 and 1 returns the corresponding output values
(e.g., scales::pal_area()
).
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.
One of:
NULL
for no breaks
waiver()
for the default breaks computed by the
transformation object
A numeric vector of positions
A function that takes the limits as input and returns breaks
as output (e.g., a function returned by scales::extended_breaks()
).
Note that for position scales, limits are provided after scale expansion.
Also accepts rlang lambda function notation.
One of:
NULL
for no labels
waiver()
for the default labels computed by the
transformation object
A character vector giving labels (must be same length as breaks
)
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.
One of:
NULL
to use the default scale range
A numeric vector of length two providing limits of the scale.
Use NA
to refer to the existing minimum or maximum
A function that accepts the existing (automatic) limits and returns
new limits. Also accepts rlang lambda function
notation.
Note that setting limits on positional scales will remove data outside of the limits.
If the purpose is to zoom, use the limit argument in the coordinate system
(see coord_cartesian()
).
Should unused factor levels be omitted from the scale? The default, TRUE, uses the levels that appear in the data; FALSE uses all the levels in the factor.
For position scales, The position of the axis.
left
or right
for y axes, top
or bottom
for x axes.
A function used to scale the input values to the
range [0, 1]. This is always scales::rescale()
, except for
diverging and n colour gradients (i.e., scale_colour_gradient2()
,
scale_colour_gradientn()
). The rescaler
is ignored by position
scales, which always use scales::rescale()
. Also accepts rlang
lambda function notation.
One of:
Function that handles limits outside of the scale limits (out of bounds). Also accepts rlang lambda function notation.
The default (scales::censor()
) replaces out of
bounds values with NA
.
scales::squish()
for squishing out of bounds values into range.
scales::squish_infinite()
for squishing infinite values into range.
The super class to use for the constructed scale
A function with the same arguments as scale_function
that works with discretised
values.
This scale makes it very easy to synchronise the breaks of filled contours
and the breaks shown no the colour guide. Bear in mind that when using
geom_contour_fill()
, the default fill aesthetic (level_mid
) is not
discretised. To use this scale with that geom, you need to set
aes(fill = after_stat(level))
.
scale_fill_discretised
library(ggplot2)
scale_fill_brewer_discretised <- as.discretised_scale(scale_fill_distiller)
library(ggplot2)
# Using the `level` compute aesthetic from `geom_contour_fill()`
# (or ggplot2::geom_contour_filled()), the default scale is discrete.
# This means that you cannot map colours to the underlying numbers.
v <- ggplot(faithfuld, aes(waiting, eruptions, z = density))
v + geom_contour_fill(aes(fill = after_stat(level)))
v + geom_contour_fill(aes(fill = after_stat(level))) +
scale_fill_discretised()
# The scale can be customised the same as any continuous colour scale
v + geom_contour_fill(aes(fill = after_stat(level))) +
scale_fill_discretised(low = "#a62100", high = "#fff394")
# Setting limits explicitly will truncate the scale
# (if any limit is inside the range of the breaks but doesn't
# coincide with any range, it will be rounded with a warning)
v + geom_contour_fill(aes(fill = after_stat(level))) +
scale_fill_discretised(low = "#a62100", high = "#fff394",
limits = c(0.01, 0.028))
#> Warning: User supplied limits don't correspond to valid breaks. [0.01, 0.028] rounded to [0.01, 0.03]
# Or extend it.
v + geom_contour_fill(aes(fill = after_stat(level))) +
scale_fill_discretised(low = "#a62100", high = "#fff394",
limits = c(0, 0.07))
v + geom_contour_fill(aes(fill = after_stat(level))) +
scale_fill_divergent_discretised(midpoint = 0.02)
# Existing continous scales can be "retrofitted" by changing the `super`
# and `guide` arguments.
v + geom_contour_fill(aes(fill = after_stat(level))) +
scale_fill_distiller(super = ScaleDiscretised)
# Unequal breaks will, by default, map to unequal spacing in the guide
v + geom_contour_fill(aes(fill = after_stat(level)), breaks = c(0, 0.005, 0.01, 0.02, 0.04)) +
scale_fill_discretised()
# You can change that by the `even.steps` argument on ggplot2::guide_colorsteps()
v + geom_contour_fill(aes(fill = after_stat(level)), breaks = c(0, 0.005, 0.01, 0.02, 0.04)) +
scale_fill_discretised(guide = guide_colorsteps(even.steps = TRUE, show.limits = TRUE))