This function is currently not documented; only the argument list is available.
This function is EXPERIMENTAL. The behaviour of this function, the name of this function, and anything else documented about this function may change without notice in a future release of PHP. Use this function at your own risk.
Sets the value of the specified channel of this object to the provided value, which should be between 0 and 1. This function can be used to provide an opacity channel to an ImagickPixel object.
One of the Imagick channel color constants.
The value to set this channel to, ranging from 0 to 1.