This function creates colors corresponding to the given intensities (between 0 and
max) of the red, green and blue primaries. The colour specification refers to the standard sRGB colorspace (IEC standard 61966).
An alpha transparency value can also be specified (as an opacity, so
max means opaque). If
alpha is not specified, an opaque colour is generated.
names argument may be used to provide names for the colors.
rgb(red, green, blue, alpha, names = NULL, maxColorValue = 1)
- red, blue, green, alpha
- numeric vectors with values in [0, M] where M is
maxColorValue. When this is
alphavalues are coerced to integers in
0:255and the result is computed most efficiently.
- character. The names for the resulting vector.
- number giving the maximum of the color values range, see above.
The colors may be specified by passing a matrix or data frame as argument
red, and leaving
green missing. In this case the first three columns of
red are taken to be the
Semi-transparent colors (
0 < alpha < 1) are supported only on some devices: at the time of writing on the
X11(type = "cairo") devices and associated bitmap devices (
bitmap). They are supported by several third-party devices such as those in packages Cairo, cairoDevice and JavaGD. Only some of these devices support semi-transparent backgrounds.
Most other graphics devices plot semi-transparent colors as fully transparent, usually with a warning when first encountered.
A character vector with elements of 7 or 9 characters,
"#" followed by the red, blue, green and optionally alpha values in hexadecimal (after rescaling to
0 ... 255). The optional alpha values range from
R does not use ‘premultiplied alpha’.
Documentation reproduced from R 3.0.2. License: GPL-2.