pChart设置Y轴标签间距

Question

我想在pChart中规定y轴标签的间距。下面给出了下面的图表，但我想将y轴设置为1步。

$AxisBoundaries = array(0=>array("Min"=>0,"Max"=>4));
$myPicture->drawScale(array("Mode"=>SCALE_MODE_MANUAL, "ManualScale"=>$AxisBoundaries));