as.color: Transform vector of values into color specification
Description
Convenience function to convert a vector of values into a color
specification.
Usage
as.color(x, opacity = 1)
is.color(x)
Value
For as.color, a vector integer values (corresponding to color
palette values) or character color name. For is.color, a logical
vector indicating if each element of x appears to be a color
as.color() returns TRUE if x is a character in a known color format.
Arguments
x
vector of numeric, character or factor values to be transformed
opacity
optional numeric value in the range 0.0 to 1.0 used to specify
the opacity/transparency (alpha) of the colors to be returned. 0 means
fully opaque, 1 means fully transparent.
Behavior of as.color is as follows:
integer numeric
values: unchanged, (assumed to corespond to values of R's active
palette)
integer real values: will be translated to into
grayscale values ranging between the max and min
factor: integer
values corresponding to factor levels will be used
character: if
values are valid colors (as determined by is.color) they will be
returned as is. Otherwise converted to factor and numeric value of factor
returned.
The optional opacity parameter can be used to make colors partially
transparent (as a shortcut for adjustcolor. If used, colors
will be returned as hex rgb color string (i.e. "#00FF0080")
The is.color function checks if each character element of x
appears to be a color name by comparing it to colors and
checking if it is an HTML-style hex color code. Note that it will return
FALSE for integer values.
These functions are used for the color parameters of
plot.network.