Question

我已生成图表：

library(DiagrammeR)
grViz("
digraph boxes_and_circles {

  # a 'graph' statement
  graph [layout = neato, overlap = true, fontsize = 10, outputorder = edgesfirst]

  # several 'node' statements
  node [shape = circle,
  fontname = Helvetica]
  A [pos = '1,1!']; 
  B [pos = '0,2!']; 
  C [pos = '1.5,3!']; 
  D [pos = '2.5,1!']; 
  E [pos = '4,1!']; 
  F [pos = '4,2!']; 
  G [pos = '5,1!']; 
  H [pos = '6,2!']; 
  I [pos = '1.5,-0.1!'];

  # several 'edge' statements
  A->B B->C
  D->E D->F E->F E->G F->G G->H F->H
  }
  ")

产生：

现在我想在节点A，B和C周围画一个带虚线的方框。

如何在R中完成此操作？该解决方案的一个关键要求是它是可重现的，即我可以多次运行脚本并获得相同的结果。

Answer 1

Here's another approach based on igraph. It is inspired by this igraph code sample.

I'm assuming that using igraph instead of DiagrammeR is an option - maybe that is not the case...

We leave positioning of the vertices to a standard layout algorithm and query it for the resulting vertex positions. These positions are then used to draw a dotted rectangle around an arbitrary set of "selected" vertices. No user interaction is needed.

We start with the graph topology.

library(igraph)

set.seed(42)

df <- data.frame(from = c('A', 'B', 'I', 'D', 'D', 'E', 'E', 'F', 'F', 'G'),
                 to = c('B', 'C', 'I', 'E', 'F', 'G', 'F', 'H', 'G', 'H'))

g <- graph.data.frame(df, directed = TRUE)

The size of the vertices and arrows in the graph can be set freely, according to taste.

vertexsize <- 50
arrowsize <- 0.2

We ask the Fruchterman-Reingold layout engine to calculate the coordinates of the vertices.

coords <- layout_with_fr(g)

Then plot the graph.

plot(g,
     layout = coords,
     vertex.size = vertexsize,
     edge.arrow.size = arrowsize,
     rescale = FALSE,
     xlim = range(coords[,1]),
     ylim = range(coords[,2]))

If we like to see what's going on, we can add coordinate axes and print the vertex coordinates:

axis(1)
axis(2)

V(g) # ordered vertex list
coords # coordinates of the vertices (in the same coordinate system as our dotted rectangle)

We now figure out the bounding box of the vertices that we want a rectangle around.

selectedVertices = c("A", "B", "C")
vertexIndices <- sapply(selectedVertices, FUN = function(x) { return(as.numeric(V(g)[x])) } )
llx <- min(coords[vertexIndices, 1])
lly <- min(coords[vertexIndices, 2])
urx <- max(coords[vertexIndices, 1])
ury <- max(coords[vertexIndices, 2])

Almost there. We already have the coordinates of the vertex centers in coords[], but we also need the size of the vertices in the coordinate system of plot(). From the plot.igraph source code we can see that the vertex.size option for plot() gets divided by 200 and then used as radius for drawing the vertex. We use a 50% bigger value as the margin around the bounding box of the vertex coordinates when drawing the dotted rectangle.

margin <- (vertexsize / 200) * 1.5
rect(llx - margin, lly - margin, urx + margin, ury + margin, lty = 'dotted')

This is the result we get:

Answer 2

您可以使用@ StevenBeaupre的小部件解决方案，但是有一些使用R＆C的图形绘制网络的软件包。如果您愿意使用其他解决方案，则一个是igraph。

这将生成图表

library('igraph')
set.seed(11)
g <- data.frame(from = c('A', 'B', 'I', 'D', 'D', 'E', 'E', 'F', 'F', 'G'),
                to = c('B', 'C', 'I', 'E', 'F', 'G', 'F', 'H', 'G', 'H'))
(gg <- graph.data.frame(g, directed = TRUE))
plot(gg, vertex.color = 'white')

有很多方法可以为r图形添加一个盒子;在这里你可以点击图表来添加框而不必计算任何东西

rekt <- function(...) {
  coords <- c(unlist(locator(1)), unlist(locator(1)))
  rect(coords[1], coords[2], coords[3], coords[4], ..., xpd = NA)
}

rekt(border = 'red', lty = 'dotted', lwd = 2)

我明白了

Answer 3

使用DiagrammR的简单解决方案是使用点而不是neato。您几乎失去了手动定位节点的能力（属性pos不再起作用），但您可以使用集群和子图在节点集周围绘制线条。

library(DiagrammeR)
grViz("
      digraph boxes_and_circles {

      # a 'graph' statement
      graph [ fontsize = 10,rankdir=LR]

      # several 'node' statements
      node [shape = circle,
      fontname = Helvetica]

      # several 'edge' statements

      subgraph cluster_1 {
            style=dotted
            A->B->C
        }

      D->E D->F E->F E->G F->G G->H F->H
      I
      }

      ")

手动绘制图形

3 个答案: