Imagick::contrastStretchImage

(PECL imagick 2.0.0)

Imagick::contrastStretchImage — Enhances the contrast of a color image

说明

Imagick::contrastStretchImage ( float $black_point , float $white_point [, int $channel = Imagick::CHANNEL_DEFAULT ] ) : bool

Enhances the contrast of a color image by adjusting the pixels color to span the entire range of colors available. 此方法在Imagick基于ImageMagick 6.2.9以上版本编译时可用。

参数

black_point: The black point.
white_point: The white point.
channel: Provide any channel constant that is valid for your channel mode. To apply to more than one channel, combine channeltype constants using bitwise operators. Imagick::CHANNEL_ALL. Refer to this list of channel constants.

返回值

成功时返回 TRUE。