(PECL imagick 2.0.0)
Imagick::sigmoidalContrastImage — Adjusts the contrast of an image
$sharpen
, float $alpha
, float $beta
[, int $channel = Imagick::CHANNEL_ALL
] )
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.
sharpen
alpha
beta
channel
Întoarce TRUE în caz de succes.
Emite ImagickException în caz de eroare.