Imagick::contrastStretchImage
(PECL imagick 2.0.0)
Imagick::contrastStretchImage — Enhances the contrast of a color image
说明
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
。