The Imagick class
PHP Manual

Imagick::sigmoidalContrastImage

(PECL imagick 2.0.0)

Imagick::sigmoidalContrastImageAdjusts the contrast of an image

Descrição

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

Esta função não está documentada; somente a lista de argumentos está disponível.

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.

Parâmetros

sharpen

alpha

beta

channel

Valor Retornado

Retorna TRUE em sucesso.

Erros

Dispara ImagickException em erro.


The Imagick class
PHP Manual