feat: edge color by variable

[teofiln]

Hi @JohnCoene

Please have a look at this PR. It allows the user to pass a color variable to map onto the edges color in e_graph, independent of node color. For example:

nodes <- data.frame(
    name = c("A", "B", "C", "D", "E"),
    value = c("A", "B", "C", "D", "E"),
    group = c("gr1", "gr1", "gr2", "gr2", "gr3"),
    size = 3:7 * 10,
    x = c(0, 200, 400, 600, 800),
    y = c(100, 100, 200, 200, 0)
)

edges <- data.frame(
    source = c("A", "B", "C", "D", "E"),
    target = c("B", "C", "D", "E", "D"),
    size = rep(3, 5),
    color = c("red", "green", "blue", "yellow", "black")
)

devtools::load_all()
e_charts() |>
    e_graph(layout = "none", autoCurveness = TRUE) |>
    e_graph_nodes(nodes, name, value, size, category = group, xpos = x, ypos = y) |>
    e_graph_edges(edges, source, target, size = size, color = color) |>
    e_tooltip()

[JohnCoene]

Looks good, thank you!