(No version information available, might only be in SVN)
Imagick::extentImage — Set image size
$width
   , int $height
   , int $x
   , int $y
   )Comfortability method for setting image size. The method sets the image size and allows setting x,y coordinates where the new area begins. 此方法在Imagick基于ImageMagick 6.3.1以上版本编译时可用。
width
     The new width
height
     The new height
x
     X position for the new size
y
     Y position for the new size
   成功时返回 TRUE .