start/end_cap for 0-version

[David Schoch]

It would be nice if start/end cap would also work for the 0 version (if there is nothing obvious that would forbid it).

library(igraph)
library(ggraph)

g <- make_full_graph(3)

ggraph(g, "stress") + 
  geom_edge_link0(start_cap = circle(25,"pt"), end_cap = circle(25,"pt"))+
  geom_node_point(size = 15)
#> Warning: Ignoring unknown parameters: start_cap, end_cap

I usually use this workaround to add an end_cap

ggraph(g, "stress") + 
  geom_edge_link(end_cap = circle(25,"pt"), n = 2)+
  geom_node_point(size = 15)

When specifying an additional start cap, then the edges disappear

ggraph(g, "stress") + 
  geom_edge_link(start_cap = circle(25,"pt"),end_cap = circle(25,"pt"), n = 2)+
  geom_node_point(size = 15)

When setting n=3, they appear again

ggraph(g, "stress") + 
  geom_edge_link(start_cap = circle(25,"pt"),end_cap = circle(25,"pt"), n = 3)+
  geom_node_point(size = 15)

i guess this might be related to #325

^{Created on 2022-09-05 by the reprex package (v2.0.1)}

[Thomas Lin Pedersen]

it is not possible - the 0-versions by design uses the classic low-level grows from grid and we can thus not cap them... they should not just disappear