hsv {grDevices} | 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, alpha)

### 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* |

`alpha` |
numeric vector of values in the range `[0,1]` for
alpha transparency channel (0 means transparent and 1 means opaque). |

### Details

Semi-transparent colors (`0 < alpha < 1`

) are supported only on a
few devices: at the time of writing only on the `pdf`

and
(on MacOS X) `quartz`

devices.

### 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

`hcl`

for a perceptually based version of `hsv()`

,
`rgb`

and `rgb2hsv`

for RGB to HSV conversion;
`rainbow`

,
`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)

[Package

*grDevices* version 2.5.0

Index]