Wrapper around ggplot's `scale_colour_gradient2`

with
inverted defaults of `high`

and `low`

.

```
scale_colour_divergent(
...,
low = scales::muted("blue"),
mid = "white",
high = scales::muted("red"),
midpoint = 0,
space = "Lab",
na.value = "grey50",
guide = "colourbar"
)
scale_color_divergent(
...,
low = scales::muted("blue"),
mid = "white",
high = scales::muted("red"),
midpoint = 0,
space = "Lab",
na.value = "grey50",
guide = "colourbar"
)
scale_fill_divergent(
...,
low = scales::muted("blue"),
mid = "white",
high = scales::muted("red"),
midpoint = 0,
space = "Lab",
na.value = "grey50",
guide = "colourbar"
)
```

- ...
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::area_pal()`

).`name`

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.`breaks`

One of:

`NULL`

for no breaks`waiver()`

for the default breaks computed by the transformation objectA 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()`

). Also accepts rlang lambda function notation.

`minor_breaks`

One of:

`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 objectA 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 rangeA numeric vector of length two providing limits of the scale. Use

`NA`

to refer to the existing minimum or maximumA 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`

For continuous scales, the name of a transformation object or the object itself. Built-in transformations include "asn", "atanh", "boxcox", "date", "exp", "hms", "identity", "log", "log10", "log1p", "log2", "logit", "modulus", "probability", "probit", "pseudo_log", "reciprocal", "reverse", "sqrt" and "time".

A transformation object bundles together a transform, its inverse, and methods for generating breaks and labels. Transformation objects are defined in the scales package, and are called

`<name>_trans`

(e.g.,`scales::boxcox_trans()`

). You can create your own transformation with`scales::trans_new()`

.`expand`

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`expand`

argument. 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.`position`

For position scales, The position of the axis.

`left`

or`right`

for y axes,`top`

or`bottom`

for x axes.`super`

The super class to use for the constructed scale

- low, high
Colours for low and high ends of the gradient.

- mid
colour for mid point

- midpoint
The midpoint (in data value) of the diverging scale. Defaults to 0.

- space
colour space in which to calculate gradient. Must be "Lab" - other values are deprecated.

- na.value
Colour to use for missing values

- guide
Type of legend. Use

`"colourbar"`

for continuous colour bar, or`"legend"`

for discrete colour legend.

Other ggplot2 helpers:
`DivideTimeseries()`

,
`MakeBreaks()`

,
`WrapCircular()`

,
`geom_arrow()`

,
`geom_contour2()`

,
`geom_contour_fill()`

,
`geom_label_contour()`

,
`geom_relief()`

,
`geom_streamline()`

,
`guide_colourstrip()`

,
`map_labels`

,
`reverselog_trans()`

,
`scale_longitude`

,
`stat_na()`

,
`stat_subset()`

```
library(ggplot2)
ggplot(reshape2::melt(volcano), aes(Var1, Var2, z = value)) +
geom_contour(aes(color = after_stat(level))) +
scale_colour_divergent(midpoint = 130)
```