如何在Diagrammer，R中反转箭头（尾部）？

Question

让我们创建一个非常简单的图表：

niv <- c("A","B","C","D","E")
from <- c("A","A","A","E","B","C","D")
to <-   c("B","C","D","B","C","A","E")
arr <- c(rep("normal",6), "inv")
temp <- data.table(from=factor(from, levels=niv), 
to=factor(to,levels=niv))
nodes <- create_node_df(n=length(niv), label=niv,
width=0.3) 
edges <- create_edge_df(from = temp$from,
to = temp$to, rel = "leading_to", label=temp$from,
arrowhead=arr, penwidth=3, color="blue")   
graph <- create_graph(nodes_df=nodes,edges_df=edges)
render_graph(graph)

该图显示了从一个节点到另一个节点的边缘 通常人们用箭头涂上那些边缘，但我想画一些带有相反符号的东西。

我发现通过使用参数 arrowhead =＆＃34; inv＆＃34; ，我可以将箭头改为尾巴。 （在我的例子中，从D到E的边有一个尾）。

但是有一个问题，尾巴被涂错了。我想在边缘的开头绘制它（箭头）。

如何更改？

有一个参数rel =＆＃34; leading_to＆＃34;但我还没能找到它能得到的其他价值 还有一个参数＆＃34; dir＆＃34;但我也不知道如何使用它。

感谢。

一个额外的问题是：如何阻止Diagrammer在边缘上方写标签？我希望他们不会重叠。

Answer 1

您可以将目录切换为“后退”：

library(DiagrammeR)
library(data.table)
niv <- c("A","B","C","D","E")
from <- c("A","A","A","E","B","C","D")
to <-   c("B","C","D","B","C","A","E")
temp <- data.table(from=factor(from, levels=niv), 
                   to=factor(to,levels=niv))
nodes <- create_node_df(n=length(niv), label=niv,
                        width=0.3) 
edges <- create_edge_df(from = temp$from,
                        to = temp$to, dir = "back", label=temp$from,
                        arrowtail="inv", penwidth=3, color="blue")   
graph <- create_graph(nodes_df=nodes,edges_df=edges)
render_graph(graph)