[PATCH dpdk] graph: make graphviz export more readable

[Robin Jarry]

Change the color of arrows leading to sink nodes to dark orange. Remove
the node oval shape around the sink nodes and make their text dark
orange. This results in a much more readable output for large graphs.
See the link below for an example.

Link: https://f.jarry.cc/rte-graph-dot/ipv6.svg
Signed-off-by: Robin Jarry <rjarry at redhat.com>
---
 lib/graph/graph.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/lib/graph/graph.c b/lib/graph/graph.c
index d5b8c9f918cf..dff8e690a80d 100644
--- a/lib/graph/graph.c
+++ b/lib/graph/graph.c
@@ -745,7 +745,7 @@ graph_to_dot(FILE *f, struct graph *graph)
 			if (rc < 0)
 				goto end;
 		} else if (graph_node->node->nb_edges == 0) {
-			rc = fprintf(f, " [color=darkorange]");
+			rc = fprintf(f, " [fontcolor=darkorange shape=plain]");
 			if (rc < 0)
 				goto end;
 		}
@@ -753,9 +753,12 @@ graph_to_dot(FILE *f, struct graph *graph)
 		if (rc < 0)
 			goto end;
 		for (i = 0; i < graph_node->node->nb_edges; i++) {
+			const char *node_attrs = attrs;
+			if (graph_node->adjacency_list[i]->node->nb_edges == 0)
+				node_attrs = " [color=darkorange]";
 			rc = fprintf(f, "\t\"%s\" -> \"%s\"%s;\n", node_name,
 				     graph_node->adjacency_list[i]->node->name,
-				     attrs);
+				     node_attrs);
 			if (rc < 0)
 				goto end;
 		}
-- 
2.46.0