A color component used to define the gray level required.
A number between 0 and 1, or nil
.
Return a color-spec in the :GRAY
model with component
level
.
Note that short-floats are used for the component; this results in the most efficient color conversion process. However, any floating point number type can be used.
alpha
indicates the alpha value of the color. 0 means it is transparent, 1 means it is solid. If
alpha
is nil
or not specified then the color does not have an alpha component and it is assumed to be solid.
CAPI User Guide and Reference Manual (Unix version) - 3 Aug 2017