(PECL imagick 2 >= 2.2.1, PECL imagick 3)
Imagick::getImageChannelRange — Gets channel range
Gets the range for one or more image channels. 此方法在Imagick基于ImageMagick 6.4.0以上版本编译时可用。
channel
Provide any channel constant that is valid for your channel mode. To apply to more than one channel, combine channel constants using bitwise operators. 缺省为Imagick::CHANNEL_DEFAULT.
参考此 通道常数列表
Returns an array containing minima and maxima values of the channel(s).
错误时抛出 ImagickException。