(PECL imagick 2.0.0)
Imagick::vignetteImage — Adds vignette filter to the image
$blackPoint
   , float $whitePoint
   , int $x
   , int $y
   )Softens the edges of the image in vignette style. This method is available if Imagick has been compiled against ImageMagick version 6.2.9 or newer.
blackPoint
     The black point.
whitePoint
     The white point
x
     X offset of the ellipse
y
     Y offset of the ellipse
   Returns TRUE on success.