`divergingx_hcl.Rd`

Diverging HCL color palettes generated through combination of two fully flexible (and possibly unbalanced) multi-hue sequential palettes.

```
divergingx_hcl(
n,
palette = "Geyser",
...,
fixup = TRUE,
alpha = 1,
rev = FALSE,
h1,
h2,
h3,
c1,
c2,
c3,
l1,
l2,
l3,
p1,
p2,
p3,
p4,
cmax1,
cmax2
)
divergingx_palettes(palette = NULL, plot = FALSE, n = 7L, ...)
```

- n
the number of colors (\(\ge 1\)) to be in the palette.

- palette
character with the name (see details).

- ...
arguments passed to

`hex`

.- fixup
logical. Should the color be corrected to a valid RGB value?

- alpha
numeric vector of values in the range

`[0, 1]`

for alpha transparency channel (0 means transparent and 1 means opaque).- rev
logical. Should the palette be reversed?

- h1
numeric. Starting hue coordinate.

- h2
numeric. Center hue coordinate.

- h3
numeric. Ending hue coordinate.

- c1
numeric. Chroma coordinate corresponding to

`h1`

.- c2
numeric. Chroma coordinate corresponding to

`h2`

(if`NA`

, set to 0).- c3
numeric. Chroma coordinate corresponding to

`h3`

.- l1
numeric. Luminance coordinate corresponding to

`h1`

.- l2
numeric. Luminance coordinate corresponding to

`h2`

.- l3
numeric. Luminance coordinate corresponding to

`h3`

(if`NA`

,`l1`

is used).- p1
numeric. Power parameter for chroma coordinates in first sequential palette.

- p2
numeric. Power parameter for luminance coordinates in first sequential palette (if

`NA`

,`p1`

is used).- p3
numeric. Power parameter for chroma coordinates in second sequential palette (if

`NA`

,`p1`

is used).- p4
numeric. Power parameter for luminance coordinates in second sequential palette (if

`NA`

,`p3`

is used).- cmax1
numeric. Maximum chroma coordinate in first sequential palette (not used if

`NA`

).- cmax2
numeric. Maximum chroma coordinate in second sequential palette (if

`NA`

,`cmax1`

is used).- plot
logical. Should the selected HCL color palettes be visualized?

A character vector with (s)RGB codings of the colors in the palette.

The `divergingx_hcl`

function simply calls `sequential_hcl`

twice with a prespecified set of hue, chroma, and luminance parameters. This is
similar to `diverging_hcl`

but allows for more flexibility:
`diverging_hcl`

employs two *single-hue* sequential palettes,
always uses zero chroma for the neutral/central color, and restricts the
chroma/luminance path to be the same in both “arms” of the palette.
In contrast, `divergingx_hcl`

relaxes this to two full *multi-hue*
palettes that can thus go through a non-gray neutral color (typically light
yellow). Consequently, the chroma/luminance paths can be rather unbalanced
between the two arms.

With this additional flexibility various diverging palettes suggested by https://ColorBrewer2.org/ and CARTO (https://carto.com/carto-colors/), can be emulated along with the Zissou 1 palette from wesanderson, Cividis from viridis, and Roma from scico.

Available CARTO palettes: ArmyRose, Earth, Fall, Geyser, TealRose, Temps, and
Tropic (with Tropic also available in `diverging_hcl`

).

Available ColorBrewer.org palettes: PuOr, RdBu, RdGy, PiYG, PRGn, BrBG, RdYlBu, RdYlGn, Spectral.

Zeileis A, Fisher JC, Hornik K, Ihaka R, McWhite CD, Murrell P, Stauffer R, Wilke CO (2020).
“colorspace: A Toolbox for Manipulating and Assessing Colors and Palettes.”
*Journal of Statistical Software*, **96**(1), 1--49. doi:10.18637/jss.v096.i01

```
## show emulated CARTO/ColorBrewer.org palettes
divergingx_palettes(plot = TRUE)
## compared to diverging_hcl() the diverging CARTO palettes are typically warmer
## but also less balanced with respect to chroma/luminance, see e.g.,
specplot(divergingx_hcl(7, "ArmyRose"))
```