如何在倾斜图中标记中心节点？

Question

从另一个问题中使用这个可复制的例子。如何标记/着色本地邻域图所基于的中心节点。(在本例中为“x”)

library(tidygraph)
library(ggraph)


# Example
net <- tibble::tibble(A = letters[1:6],
                      B = rep(c("x", "y"), each = 3)) %>% 
  tidygraph::as_tbl_graph()

net %>%
  tidygraph::convert(to_local_neighborhood,
                     node = which(.N()$name == "x"),
                     order = 1,
                     mode = "all") %>%
  ggraph(layout = "nicely") +
  geom_edge_link() +
  geom_node_point(size = 10, fill = "white", shape = 21) +
  geom_node_text(aes(label = name)) +
  theme_graph()

我得到的是：

​

​

我想要的：

​

​

我觉得geom_node_point应该有条件填充，但我不知道这是否可能.

Answer 1

你可以：

net %>%
  tidygraph::convert(to_local_neighborhood,
                     node = which(.N()$name == 'x'),
                     order = 1,
                     mode = "all") %>%
  mutate(root = ifelse(node_is_center(), 'red', 'white')) %>%
  ggraph(layout = "nicely") +
  geom_edge_link() +
  geom_node_point(size = 10, aes(fill = root), shape = 21) +
  geom_node_text(aes(label = name)) +
  scale_fill_identity() +
  theme_graph()

​

​