Add ability to specify symbol and symbol size for edges in network graphs

[liubao210]

First of all, I've been using this package in my company for two years, it's an awesome package, I recommend it to many colleagues, thank you to all the contributors !!!

But today I found the original parameter edge symbolSize cannot be used because the value of symbolSize is incorrectly assigned to c(5, 20) at line 292 of file R/utils.R. So :

1. I delete this wrong setting, than we can set a generic symbol and symbol size of edges in e_graph()

nodes <- data.frame(
  name = paste0(LETTERS, 1:100),
  value = rnorm(100, 10, 2),
  size = rep(c(10,5), 50),
  grp = rep(c("grp1", "grp2"), 50),
  stringsAsFactors = FALSE
)

edges <- data.frame(
  source = sample(nodes$name, 200, replace = TRUE),
  target = sample(nodes$name, 200, replace = TRUE),
  value = 1,
  size = rep(c(5, 1), 100),
  stringsAsFactors = FALSE
)

e_charts() |>
  e_graph(
    label = list(show = T, position = "right"), 
    edgeSymbol = c("circle", "arrow"),
    edgeSymbolSize = c(5, 3),
    lineStyle = list(curveness = 0.2),
    draggable = T,
    roam = T
  ) |>
  e_graph_nodes(nodes, name, value, size, grp) |>
  e_graph_edges(edges, source, target, value, size)

2. Add ability for dynamic edge symbol and symbol size, which can be setted in e_graph_edges()

nodes <- data.frame(
  name = paste0(LETTERS, 1:100),
  value = rnorm(100, 10, 2),
  size = rep(c(10,5), 50),
  grp = rep(c("grp1", "grp2"), 50),
  stringsAsFactors = FALSE
)

edges <- data.frame(
  source = sample(nodes$name, 200, replace = TRUE),
  target = sample(nodes$name, 200, replace = TRUE),
  value = 1,
  size = rep(c(5, 1), 100),
  symbolSource = "circle",
  symbolTarget = "arrow",
  symbolSizeSource = rep(c(5,20), 100),
  symbolSizeTarget = rep(c(1,10), 100),
  symbolSize = rep(c(15,10), 100),
  stringsAsFactors = FALSE
)

e_charts() |>
  e_graph(
    label = list(show = T, position = "right"), 
    lineStyle = list(curveness = 0.2),
    draggable = T,
    roam = T
  ) |>
  e_graph_nodes(nodes, name, value, size, grp) |>
  e_graph_edges(edges, source, target, value, size, symbolSource, symbolTarget, symbolSizeSource, symbolSizeTarget)

[JohnCoene]

Thank you!