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  • Gmagick::levelimage()

    (PECL gmagick >= Unknown)

    Adjusts the levels of an image

    说明

    publicGmagick::levelimage(float $blackPoint,float $gamma,float $whitePoint[,int $channel= Gmagick::CHANNEL_DEFAULT]): mixed

    Adjusts the levels of an image by scaling the colors falling between specified white and black points to the full available quantum range. The parameters provided represent the black, mid, and white points. The black point specifies the darkest color in the image. Colors darker than the black point are set to zero. Mid point specifies a gamma correction to apply to the image. White point specifies the lightest color in the image. Colors brighter than the white point are set to the maximum quantum value.

    参数

    $blackPoint

    The image black point

    $gamma

    The gamma value

    $whitePoint

    The image 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. Refer to this list of channel constants.

    返回值

    Gmagick object with image levelled.

    错误/异常

    错误时抛出GmagickException