adjustcolor
Alter a color specification
Description
Transforms colors to related colors.
Usage
adjustcolor(col, alpha.f = 1, red.f = 1, green.f = 1, blue.f = 1,
offset = c(0, 0, 0, 0), transform = diag(c(red.f, green.f, blue.f,
alpha.f)))
Arguments
| col |
a vector of color strings or indices acceptable to col2rdb.
|
| alpha.f |
the factor by which to change the alpha (opacity) component of the color.
|
| red.f |
the factor by which to change the red component of the color.
|
| green.f |
the factor by which to change the green component of the color.
|
| blue.f |
the factor by which to change the blue component of the color.
|
| offset |
a vector of numbers in the range -1 to +1 giving an additive change
to the four color components.
- Negative one (-1) sets the
color component to zero.
- Positive 1 (+1) increases the color component to its maximum
value, 255.
Its length must be a multiple of 4.
|
| transform |
a 4 by 4 matrix used to multiply the input red-green-blue-alpha
values. By default, transform is constructed from the red.f, green.f,
blue.f, and alpha.f values so each is changed independently
of the others.
|
Value
returns a vector of color strings in the format "#RRGGBBAA", giving the 2-digit
hexadecimal values for the red, green, blue, and alpha (opacity) components
of the modified colors.
See Also
Examples
adjustcolor(c("red", "orange", "#004040a0"), alpha.f = 0.25) # make translucent colors