# Colors

## Colors

There are many color attributes, for lines, fills, markers, backgrounds, and foregrounds. Many colors follow a hierarchy... linecolor gets its value from seriescolor, for example, unless you override the value. This allows for you to simply set precisely what you want, without lots of boilerplate.

Color attributes will accept many different types:

• Symbols or Strings will be passed to Colors.parse(Colorant, c), so :red is equivalent to colorant"red"
• false or nothing will be converted to an invisible RGBA(0,0,0,0)
• Any Colors.Colorant, with or without alpha/opacity
• Any Plots.ColorScheme, which includes ColorVector, ColorGradient, etc

In addition, there is an extensive facility for selecting and generating color maps/gradients.

• A valid Symbol: :inferno (the default), :heat, :blues, etc
• A list of colors (or anything that can be converted to a color)
• A pre-built ColorGradient, which can be constructed with the cgrad helper function. See this short tutorial for example usage.

#### Series Colors

For series, there are a few attributes to know:

• seriescolor: Not used directly, but defines the base color for the series
• linecolor: Color of paths
• fillcolor: Color of area fill
• markercolor: Color of the interior of markers and shapes
• markerstrokecolor: Color of the border/stroke of markers and shapes

seriescolor defaults to :auto, and gets assigned a color from the color_palette based on its index in the subplot. By default, the other colors :match. (See the table below)

This color... matches this color...
linecolor seriescolor
fillcolor seriescolor
markercolor seriescolor
markerstrokecolor foregroundcolorsubplot

Note: each of these attributes have a corresponding alpha override: seriesalpha, linealpha, fillalpha, markeralpha, and markerstrokealpha. They are optional, and you can still give alpha information as part of an Colors.RGBA.

Note: in some contexts, and when the user hasn't set a value, the linecolor or markerstrokecolor may be overridden.

#### Foreground/Background

Foreground and background colors work similarly:

This color... matches this color...
backgroundcoloroutside background_color
backgroundcolorsubplot background_color
backgroundcolorlegend backgroundcolorsubplot
backgroundcolorinside backgroundcolorsubplot
foregroundcolorsubplot foreground_color
foregroundcolorlegend foregroundcolorsubplot
foregroundcolorgrid foregroundcolorsubplot
foregroundcolortitle foregroundcolorsubplot
foregroundcoloraxis foregroundcolorsubplot
foregroundcolorborder foregroundcolorsubplot
foregroundcolorguide foregroundcolorsubplot
foregroundcolortext foregroundcolorsubplot

#### Misc

• the linecolor under the default theme is not CSS-defined, but close to :steelblue.
• line_z and marker_z parameters will map data values into a ColorGradient value
• color_palette determines the colors assigned when seriescolor == :auto:

• If passed a vector of colors, it will force cycling of those colors
• If passed a gradient, it will infinitely draw unique colors from that gradient, attempting to spread them out

#### Colorschemes

Color gradients are arranged into color libraries. To get a list of color libraries, use the clibraries function. To get a list of color gradients in each library, call cgradients(library). showlibrary(library) creates a visual representation of color schemes. To change the active library, use clibrary(library). This is only necessary in the case of namespace clashes, e.g. there are multiple :blues. The gradients can be reversed by appending _r, e.g. :magma_r. The clims::NTuple{2,Number} attribute can be used to define the data values that correspond with the ends of the schemes.

The following libraries and gradients are included in Plots:

##### Plots

Created by Nathaniel J. Smith, Stefan van der Walt, and (in the case of viridis) Eric Firing. Released under CC0 license / public domain dedication. Full license info available here.

##### cmocean

Released under The MIT License (MIT) Copyright (c) 2015 Kristen M. Thyng. RGB values were taken from https://github.com/matplotlib/cmocean/tree/master/cmocean/rgb

##### colorcet

Released under The MIT License (MIT) Copyright (c) 2015 Peter Kovesi. These are the perceptually correct color maps designed by Peter Kovesi and described in Peter Kovesi. Good Colour Maps: How to Design Them. arXiv:1509.03700 [cs.GR] 2015

##### colorbrewer

Created by Cynthia Brewer, Mark Harrower, and The Pennsylvania State University. Released under the Apache License, Version 2.0. Full license info available here.