Gnuplot键：强制不均匀分割

我有四条曲线要画。前三个是彼此的变体，第四个是不同的。因此，我希望将密钥拆分为3+1。然而，使用例如

set key maxrows 3
plot sin(x),sin(2*x),sin(3*x),exp(x)

给出一个两行键

---

我可以强制gnuplot将密钥拆分为三加一吗？

除了@user8153的解决方案外，我还想建议一种更通用的解决方案。 如果你有彩色背景呢？例如：

set term wxt background rgb“grey90”

或如果 您有一个彩色的键（或图例）框。。。嗯，好吧，gnuplot不提供 钥匙盒的彩色背景。那么，如果你在钥匙后面放一个彩色矩形。 当然，您可以随时根据背景调整颜色，但我想用

lt-2

或

lt-nodraw

绘制一条不可见线会更简单

关于

lt-2

或

lt-nodraw

，我几天前刚刚在这里学到：。手册中还没有（还没有）它，尽管它似乎是从gnuplot版本5.0开始出现的

代码：

### invisible keyentry for column/row arrangement
reset session

set key top left maxrows 3
set obj 1 rect from graph 0.02,0.82 to graph 0.52,0.98 fs solid 1.0 fc rgb "grey90"
set xrange[-2:2]
set yrange[-2:2]

plot sin(x), sin(2*x), sin(3*x), exp(x), NaN lt -2 ti " "
### end of code

### invisible keyentry for column/row arrangement with transparent background
reset session

set term pngcairo transparent
set output "tbKeyRows.png"

set key top left maxrows 3
set xrange[-2:2]
set yrange[-2:2]

plot sin(x), sin(2*x), sin(3*x), exp(x), NaN lt -2 ti " "
set output
### end of code

结果：

### invisible keyentry for column/row arrangement
reset session

set key top left maxrows 3
set obj 1 rect from graph 0.02,0.82 to graph 0.52,0.98 fs solid 1.0 fc rgb "grey90"
set xrange[-2:2]
set yrange[-2:2]

plot sin(x), sin(2*x), sin(3*x), exp(x), NaN lt -2 ti " "
### end of code

### invisible keyentry for column/row arrangement with transparent background
reset session

set term pngcairo transparent
set output "tbKeyRows.png"

set key top left maxrows 3
set xrange[-2:2]
set yrange[-2:2]

plot sin(x), sin(2*x), sin(3*x), exp(x), NaN lt -2 ti " "
set output
### end of code

添加：

### invisible keyentry for column/row arrangement
reset session

set key top left maxrows 3
set obj 1 rect from graph 0.02,0.82 to graph 0.52,0.98 fs solid 1.0 fc rgb "grey90"
set xrange[-2:2]
set yrange[-2:2]

plot sin(x), sin(2*x), sin(3*x), exp(x), NaN lt -2 ti " "
### end of code

### invisible keyentry for column/row arrangement with transparent background
reset session

set term pngcairo transparent
set output "tbKeyRows.png"

set key top left maxrows 3
set xrange[-2:2]
set yrange[-2:2]

plot sin(x), sin(2*x), sin(3*x), exp(x), NaN lt -2 ti " "
set output
### end of code

事实上，我忘了有一个解决办法为彩色背景的钥匙盒。无需手动调整和摆弄箱子：

如果您想要一个透明的背景，例如使用pngcairo、pdfcairo等的网页上的图像，除了

lt-2

或

lt nodraw

，另一个解决方案是绘制一条透明线，例如透明的“黑色”

lc rgb 0xff000000

：

plot sin(x), sin(2*x), sin(3*x), exp(x), NaN lc rgb 0xff000000 ti " "

代码：

### invisible keyentry for column/row arrangement
reset session

set key top left maxrows 3
set obj 1 rect from graph 0.02,0.82 to graph 0.52,0.98 fs solid 1.0 fc rgb "grey90"
set xrange[-2:2]
set yrange[-2:2]

plot sin(x), sin(2*x), sin(3*x), exp(x), NaN lt -2 ti " "
### end of code

### invisible keyentry for column/row arrangement with transparent background
reset session

set term pngcairo transparent
set output "tbKeyRows.png"

set key top left maxrows 3
set xrange[-2:2]
set yrange[-2:2]

plot sin(x), sin(2*x), sin(3*x), exp(x), NaN lt -2 ti " "
set output
### end of code

结果：（显示在棋盘格图案前面）

---

丑陋的黑客：

设置键maxrows 3；绘制sin（x）、sin（2*x）、sin（3*x）、exp（x）、nanti“w l lc rgb”white

@user8153哈哈，是的！我试着画NaN，但没有想到白线。