(PECL imagick 2.0.0)
Enhances the contrast of a color image
bool Imagick::contrastStretchImage ( float $black_point, float $white_point [, int $channel = Imagick::CHANNEL_ALL ] )
Enhances the contrast of a color image by adjusting the pixels color to span the entire range of colors available. This method is available if Imagick has been compiled against ImageMagick version 6.2.9 or newer.
Parameters:
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.
Returns:
Returns TRUE
on success.
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