Update mpl_draw() to fix multigraph plots

rustworkx/visualization/matplotlib.py

@@ -754,6 +754,16 @@ def _connectionstyle(posA, posB, *args, **kwargs):
         else:
             line_width = width
 
+        # radius of edges
+
+        reverse_edge = np.concatenate(([dst], [src]))
+        for edge in edge_pos:  # the loop can be optimized
+            if bool(np.sum(np.all(np.equal(edge, reverse_edge)))):
+                rad = 0.25
+                break
+            else:
+                rad = 0
+
         arrow = mpl.patches.FancyArrowPatch(
             (x1, y1),
             (x2, y2),
@@ -763,7 +773,7 @@ def _connectionstyle(posA, posB, *args, **kwargs):
             mutation_scale=mutation_scale,
             color=arrow_color,
             linewidth=line_width,
-            connectionstyle=_connectionstyle,
+            connectionstyle=connectionstyle + f", rad = {rad}",
             linestyle=style,
             zorder=1,
         )  # arrows go behind nodes
@@ -1001,6 +1011,12 @@ def draw_edge_labels(
             x1 * label_pos + x2 * (1.0 - label_pos),
             y1 * label_pos + y2 * (1.0 - label_pos),
         )
+        if (n2, n1) in labels.keys():  # loop
+            x += 0.05 * label_pos
+            if n2 > n1:
+                y -= 0.25
+            else:
+                y += 0.25
 
         if rotate:
             # in degrees