Warning: This function is
currently not documented; only the argument list is
available.
Warning: 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.
Adjusts the levels of an image by scaling the colors falling
between specified white and black points to the full
available quantum range. The parameters provided represent
the black, mid, and white points. The black point specifies
the darkest color in the image. Colors darker than the black
point are set to zero. Mid point specifies a gamma
correction to apply to the image. White point specifies the
lightest color in the image. Colors brighter than the white
point are set to the maximum quantum value.
Parameters
- blackPoint
- gamma
- whitePoint
- channel
Return Values
Returns TRUE
on success.