(PECL imagick 2.0.0)
Imagick::modulateImage — Control the brightness, saturation, and hue
Lets you control the brightness, saturation, and hue of an image. Hue is the percentage of absolute rotation from the current position. For example 50 results in a counter-clockwise rotation of 90 degrees, 150 results in a clockwise rotation of 90 degrees, with 0 and 200 both resulting in a rotation of 180 degrees.
TRUE on success.