(PECL gmagick >= Unknown)
Gmagick::setsize — Sets the size of the Gmagick object
Sets the size of the Gmagick object. Set it before you read a raw image format such as RGB, GRAY, or CMYK.
columns
The width in pixels.
rows
The height in pixels.
The Gmagick object on success.
错误时抛出GmagickException.