Imagick::contrastStretchImage

(PECL imagick 2.0.0)

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

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

Warning

本函数暂无文档，仅有参数列表。

Enhances the contrast of a color image by adjusting the pixels color to span the entire range of colors available

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. Defaults to Imagick::CHANNEL_ALL. Refer to this list of channel constants.

Returns TRUE on success.