red.green: Custom Colormaps For Heat Maps

In mwrowe/microRutils: Mike Rowe's Miscellaneous R Utility Functions

Description

A set of functions that to define various attractive color scales

Usage

red.green(levels = 100, space = "rgb", thru = "black", ...)

yellow.blue(levels = 100, space = "rgb", ...)

grayscale(levels = 100, space = "rgb", ...)

jet(levels = 100, space = "rgb", ...)

purple.orange(levels = 100, space = "rgb", ...)

aqua.brown(levels = 100, space = "rgb", ...)

purple.green(levels = 100, space = "rgb", ...)

hot(levels = 100, space = "rgb", ...)

hot2(levels = 100, space = "rgb", ...)

orange.blue(levels = 100, space = "rgb", thru = "black", ...)

Arguments

levels	Integer, number of levels in the color map
space	a character string; interpolation in RGB or CIE Lab color spaces.
thru	A color, either named or as rgb() output, that will serve as midpoint for color maps that are symmetric about a central value.
...	arguments to pass to colorRamp.

Details

Many of these functions (orange.blue, yellow.blue, red.green, purple.orange, aqua.brown and purple.green) interpolate between three colors, where the function name contains the start and stop colors, and the "thru" argument is used to define a midpoint (typically black or white). Many of these were defined to accomodate people with color blindness.

Colormap functions that do not follow this convention are:

• grayscale maps shades of grey from black to white.

• hot mimics black-body radiation, passing from black to white through red, orange and yellow (like iron being heated up).

• hot2 is similar to hot, but has a more subdued shard of red as the first value after black. This is useful for de-emphasizing single data points in a heatmap of a 2D-histogram.

• jet interpolates from dark blue to dark red through shades of royal blue, cyan, green, yellow and orange.

Value

A character vector with elements of 7 or 9 characters, "#" followed by the red, blue, green and optionally alpha values in hexadecimal (after rescaling to 0 ... 255). The optional alpha values range from 0 (fully transparent) to 255 (opaque).

Author(s)

M.W.Rowe, [e-mail]

mwrowe/microRutils documentation built on June 12, 2021, 2:41 p.m.