(PECL imagick 2.0.0)
Imagick::contrastStretchImage — Enhances the contrast of a color image
Enhances the contrast of a color image by adjusting the pixels color to span the entire range of colors available. Этот метод доступен, если Imagick был скомпилирован с версией ImageMagick 6.2.9 или старше.
The black point.
The white point.
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.
В случае успешной работы возвращает TRUE.