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Imagick::contrastStretchImage

(PECL imagick 2, PECL imagick 3)

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

说明

public 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。