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.
Applies a special effect to the image, similar to the effect achieved in
a photo darkroom by selectively exposing areas of photo sensitive paper
to light. Threshold ranges from 0 to QuantumRange and is a measure of the
extent of the solarization.
Return Values
Returns TRUE
on success.