Color_scheme (gg.Gg_kit.Color

Schemes

type continuous = float -> Gg.color

The type for continuous schemes. A continuous scheme maps the unit interval [0.;1.] to colors. Values outside the interval yield undefined results.

type discrete = int -> Gg.color

The type for discrete schemes. A discrete scheme maps an integer interval [0;max] to colors, with max depending on the scheme. Values outside the interval raise Invalid_argument.

Sequential

Sequential schemes are for ordered scalar data.

val sequential_wijffelaars : 
  ?a:float ->
  ?w:float ->
  ?s:float ->
  ?b:float ->
  ?c:float ->
  h:float ->
  unit ->
  continuous

seq_wijffelaars ~a ~w ~s ~b ~c ~h () is a sequential scheme where 0. is the darkest color and 1. the lightest. The parameters are:

h in [0;2pi] the main hue, the overall color.
w in [0;1] is the hue warmth for a multi-hue scheme, defaults to 0 (single-hue scheme). Augmenting w adds yellow which makes the scheme warmer.
s in [0;1] is saturation, the overall colorfullness, defaults to 0.6.
b in [0;1] is brightness, the overall lightness, defaults to 0.75.
c in [0;1] is contrast, the lightness difference between the darkest and the ligthest colors of the scheme, defaults to 0.88.
a is the alpha component, defaults to 1..

Note. For equal b, c and w = 0, sequential schemes with different hues h have the same lightness. This can be used to generate multiple sequential schemes for multivariate data.

This implements the sequential schemes described by M. Wijffelaars et al..

val sequential_wijffelaars' : 
  ?a:float ->
  ?w:float ->
  ?s:float ->
  ?b:float ->
  ?c:float ->
  h:float ->
  size:int ->
  unit ->
  discrete

sequential_wijffelaars' ~a ~w ~s ~b ~c ~h ~size is like sequential_wijffelaars except it returns a discrete sequential scheme with size colors and c defaults to min 0.88 (0.34 +. 0.06. * n).

Multihue

val sequential_turbo : ?a:float -> unit -> continuous

sequential_turbo () is the turbo sequential scheme by Anton Mikhailov with alpha component a (defaults to 1.).

val sequential_magma : ?a:float -> unit -> continuous

sequential_magma () is the plasma color map by Stéfan van der Walt and Nathaniel Smith. with alpha component a (defaults to 1.).

val sequential_inferno : ?a:float -> unit -> continuous

sequential_inferno () is the plasma color map by Stéfan van der Walt and Nathaniel Smith. with alpha component a (defaults to 1.).

val sequential_plasma : ?a:float -> unit -> continuous

sequential_viridis () is the plasma color map by Stéfan van der Walt and Nathaniel Smith. with alpha component a (defaults to 1.).

val sequential_viridis : ?a:float -> unit -> continuous

sequential_viridis () is the viridis color map by Stéfan van der Walt, Nathaniel Smith and Eric Firing with alpha component a (defaults to 1.).

Diverging

Diverging schemes are for ordered scalar data with a defined midpoint, like zero or the data average.

val diverging_wijffelaars : 
  ?a:float ->
  ?w:float ->
  ?s:float ->
  ?b:float ->
  ?c:float ->
  ?m:float ->
  h0:float ->
  h1:float ->
  unit ->
  continuous

diverging_wijffelaars ~a ~w ~s ~b ~c ~m ~h0 ~h1 () is a diverging scheme with 0. returning the darkest color of h0, and 1. the darkest color of h1.

h0 in [0;2pi] is the hue, the overall color for lower values.
h1 in [0;2pi] is the hue, the overall color for higher values.
w in [0;1] is the hue warmth for a multi-hue scheme, defaults to 0 (single-hue scheme). Augmenting w adds yellow which makes the scheme warmer.
s in [0;1] is saturation, the overall colorfullness, defaults to 0.6.
b in [0;1] is brightness, the overall lightness, defaults to 0.75.
c in [0;1] is contrast, the lightness difference between the darkest and the ligthest colors of the scheme, defaults to 0.88.
m is the mid point position, defaults to 0.5.
a is the alpha component, defaults to 1..

This implements the diverging schemes described by M. Wijffelaars et al..

val diverging_wijffelaars' : 
  ?a:float ->
  ?w:float ->
  ?s:float ->
  ?b:float ->
  ?c:float ->
  ?m:float ->
  h0:float ->
  h1:float ->
  size:int ->
  unit ->
  discrete

diverging_wijffelaars' is like diverging_wijffelaars except it returns a discrete diverging scheme with size colors and c defaults to min 0.88 (1.0 - 0.06 *. (11 - ((n / 2) + 1))).

Cyclic

val cyclic_sinebow : ?a:float -> unit -> continuous

cylic_sinebow () is the sinebow cyclical scheme by Jim Bumgardner and Charlie Loyd.

Qualitative

Qualitative schemes are for nominal or categorical data.

type qualitative = [

| `Brewer_accent_8
| `Brewer_dark2_8
| `Brewer_paired_12
| `Brewer_pastel1_9
| `Brewer_pastel2_8
| `Brewer_set1_9
| `Brewer_set2_8
| `Brewer_set3_12
| `Tableau_10
| `Wijffelaars_17

]

The type for qualitative schemes. The suffix indicates the number of colors in the scheme.

The `Brewer_* schemes are colorbrewer schemes by Cynthia Brewer.
The `Tableau_10 scheme is by Maureen Stone.
The `Wijffelaars_17 scheme is by M. Wijffelaars.

val qualitative_size : qualitative -> int

qualitative_size q is the number of colors in q.

val qualitative : ?a:float -> qualitative -> unit -> discrete

qualitative q is the qualitative scheme q with qualitative_size q colors and alpha component a (defaults to 1.).

val qualitative_wijffelaars : 
  ?a:float ->
  ?eps:float ->
  ?r:float ->
  ?s:float ->
  ?b:float ->
  ?c:float ->
  size:int ->
  unit ->
  discrete

qualitative_wijffelaars ~a ~eps ~r ~s ~b ~c ~size () is a qualitative scheme with size colors. The parameters are:

eps in [0;1] is the hue shift, defines where the range of hues begin, defaults to 0 (yellow).
r in [0;1] is the used hue range proportion, defaults to 1.
s in [0;1] is saturation, the overall colorfullness, defaults to 0.5.
b in [0;1] is brightness, the overall lightness, defaults to 1.
c in [0;1] is contrast, the lightness difference between the darkest and the ligthest colors of the scheme, defaults to 0.5.
a is the alpha component, defaults to 1..

This implements the qualitative schemes described by M. Wijffelaars.