Gmagick::separateimagechannel()
(PECL gmagick >= Unknown)
Separates a channel from the image
说明
public Gmagick::separateimagechannel(int $channel): Gmagick
Separates a channel from the image and returns a grayscale image. A channel is a particular color component of each pixel in the image.
参数
- $channel
Identify which channel to extract: RedChannel, GreenChannel, BlueChannel, OpacityChannel, CyanChannel, MagentaChannel, YellowChannel, BlackChannel.
返回值
The Gmagick object on success
错误／异常
错误时抛出GmagickException。