Imagick::sigmoidalContrastImage
(No version information available, might be only in CVS)
Imagick::sigmoidalContrastImage — Adjusts the contrast of an image
說明
bool Imagick::sigmoidalContrastImage
( bool $sharpen
, float $alpha
, float $beta
[, int $channel
] )
Warning
此函式目前沒有參考文件；只有引數列表。
Warning
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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.
參數
- sharpen
-
- alpha
-
- beta
-
- channel
-
Return值
Returns TRUE on success.