(PECL imagick 2, PECL imagick 3)
ImagickPixelIterator::getPreviousIteratorRow — Returns the previous row
本函数还未编写文档，仅有参数列表。
Returns the previous row as an array of pixel wands from the pixel iterator.
Returns the previous row as an array of ImagickPixelWand objects from the ImagickPixelIterator, throwing ImagickPixelIteratorException on error.