| hsv {grDevices} | R Documentation |
Create a vector of colors from vectors specifying hue, saturation and value.
hsv(h = 1, s = 1, v = 1, gamma = 1, alpha)
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 |
alpha |
numeric value in the range [0,1] for
alpha transparency channel (0 means transparent and 1 means opaque). |
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.
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}).
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)