在发表文章中通常不希望饼图，柱状图等填充为实心填充，因为容易打印后无法区分，改代码可以实现虚线填充，是论文必备利器-In published articles usually do not want pie charts, bar charts, etc. filled with a solid fill, because they can not distinguish easily after printing, change the code can achieve dotted line filled paper is an essential tool