Map continuous values to colors — color_ramp

Linearly maps a numeric vector onto a color ramp, clamping values outside the given range to the range's endpoints.

Usage

color_ramp_continuous(
  values,
  clim = range(values, na.rm = TRUE),
  cmap = grDevices::hcl.colors(11),
  ...
)

Arguments

values: numeric vector of values to map to colors
clim: length-two numeric vector giving the value range to map from; values outside [clim[1], clim[2]] are clamped to the nearer endpoint before mapping. Default is range(values, na.rm = TRUE)
cmap: the color ramp to map onto: either a vector of colors (passed to colorRamp to build the ramp function) or a function such as the one returned by colorRamp that takes a numeric vector with elements in [0, 1] and returns an n x 3 (or n x 4, with alpha) matrix of color-channel values in [0, 255]. Default is grDevices::hcl.colors(11)
...: passed to colorRamp when cmap is a vector of colors (for example, alpha = TRUE to build an alpha-aware ramp)

Value

A character vector of '#RRGGBB' (or '#RRGGBBAA') color strings, the same length as values.

Examples


x <- rnorm(100)
col <- color_ramp_continuous(x)

plot(x, col = col, pch = 16)



# Change color palettes with vector of colors
col <- color_ramp_continuous(
  x, cmap = c("lightgreen", "white", "pink"))
plot(x, col = col, pch = 16)


# Using colorRamp
col <- color_ramp_continuous(
  x, cmap = colorRamp(c("black", "orangered", "orange")))
plot(x, col = col, pch = 16)


# Using color ramp palette `function(n) { ... }`
col <- color_ramp_continuous(
  x, cmap = hcl.colors, palette = "Blue-Red 3")
plot(x, col = col, pch = 16)


# Set range
col <- color_ramp_continuous(
  x, clim = c(0, 1),
  cmap = c("black", "orangered", "orange"))
plot(x, col = col, pch = 16)