相关疑难解决方法(0)

我想用gnuplot绘制一个18x18矩阵.这是我的代码:

set size ratio 1
set palette gray negative
set xrange[-0.5:17.5]
set yrange[-0.5:17.5]
set cbrange[-0.2:0.8]
set xtics 0,1,17
set ytics 0,1,17
set xtics offset -0.5,0
set title "Resolusition Matrix for E"
plot "Mat" matrix w image noti

然后我得到了这样的无花果:

现在我想为每个单元格添加边框,如下所示:

谢谢.