Generate a vertical colorbar image — colorbar

Creates a vertical colorbar as a 4-channel RGBA array.

Usage

colorbar_vertical(
  colormap,
  n_colors = 256L,
  width = 80L,
  height = 600L,
  ticks = NULL,
  tick_labels = NULL,
  data_range = c(0, 1),
  label_cex = 1,
  title = NULL,
  background = c(1, 1, 1, 1)
)

Arguments

colormap: A vector of colors or a function returning colors.
n_colors: Number of discrete color segments in the gradient.
width: Output width in pixels.
height: Output height in pixels.
ticks: Numeric vector of tick positions in data units. If NULL, ticks are computed automatically via pretty() restricted to the data range.
tick_labels: Character vector of tick labels.
data_range: The data range that ticks are specified in.
label_cex: Label size multiplier.
title: Optional title string drawn to the right of the color strip.
background: Background RGBA color (0-1 scale).

Value

A 3D array of dimensions (height, width, 4) with values in [0, 1].

Examples

cbar <- colorbar_vertical(viridis_colormap, data_range = c(0, 100),
    title = "Count")
dim(cbar)
#> [1] 600  80   4