Imagick Image Library
PHP Manual

Imagick::sigmoidalContrastImage

(No version information available, might be only in CVS)

Imagick::sigmoidalContrastImage — Adjusts the contrast of an image

Description

bool Imagick::sigmoidalContrastImage ( bool $sharpen , float $alpha , float $beta [, int $channel ] )
Warning

此函數目前沒有參考文件;只有引數列表。

Warning

這個函數是實驗性質的。這個函數的行為、名稱、和關於此函數的任何其他文件在未來PHP的發行中可能會在不通知的情況下改變。 使用此延伸需自行承擔風險。

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.

Parameters

sharpen

alpha

beta

channel

Return Values

Returns TRUE on success.


Imagick Image Library
PHP Manual