Imagick::sigmoidalContrastImage
(No version information available, might be only in CVS)
Imagick::sigmoidalContrastImage — Adjusts the contrast of an image
说明
本函数暂无文档，仅有参数列表。
本函数是实验性的。本函数的行为，包括函数名称以及其它任何关于本函数的文档可能会在没有通知的情况下随 PHP 以后的发布而改变。使用本函数风险自担。
Adjusts the contrast of an image with a non-linear sigmoidal contrast algorithm. Increase the contrast of the image using a sigmoidal transfer function without saturating highlights or shadows. Contrast indicates how much to increase the contrast (0 is none; 3 is typical; 20 is pushing it); mid-point indicates where midtones fall in the resultant image (0 is white; 50 is middle-gray; 100 is black). Set sharpen to true to increase the image contrast otherwise the contrast is reduced.
参数
- sharpen
-
- alpha
-
- beta
-
- channel
-
返回值
Returns TRUE on success.
