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
] )
WarningThis function is
currently not documented; only its argument list is available.
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.
Errors/Exceptions
Throws ImagickException on error.