hsv {graphics}R Documentation

HSV Color Specification

Description

Create a vector of colors from vectors specifying hue, saturation and value.

Usage

hsv(h=1, s=1, v=1, gamma=1)

Arguments

h,s,v numeric vectors of values in the range [0,1] for “hue”, “saturation” and “value” to be combined to form a vector of colors. Values in shorter arguments are recycled.
gamma a “gamma correction” exponent, gamma

Value

This function creates a vector of “colors” corresponding to the given values in HSV space. The values returned by hsv can be used with a col= specification in graphics functions or in par.

Gamma correction

For each color, (r,g,b) in RGB space (with all values in [0,1]), the final color corresponds to (r^{gamma}, g^{gamma}, b^{gamma}).

See Also

rainbow, rgb, gray.

Examples

hsv(.5,.5,.5)

## Look at gamma effect:
n <- 20;  y <- -sin(3*pi*((1:n)-1/2)/n)
op <- par(mfrow=c(3,2),mar=rep(1.5,4))
for(gamma in c(.4, .6, .8, 1, 1.2, 1.5))
  plot(y, axes = FALSE, frame.plot = TRUE,
       xlab = "", ylab = "", pch = 21, cex = 30,
       bg = rainbow(n, start=.85, end=.1, gamma = gamma),
       main = paste("Red tones;  gamma=",format(gamma)))
par(op)

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