ENH(plot); from-data edges as dot

Author: ankostis

graphtik/plot.py

@@ -612,6 +612,8 @@ class Theme:
     ##
 
     kw_edge = {"tailport": "s", "headport": "n"}
+    kw_edge_tail_op = {}
+    kw_edge_head_op = {"arrowtail": "dot", "dir": "both"}
     kw_edge_optional = {"style": ["dashed"]}
     kw_edge_sideffect = {"color": "blue"}
     #: Added conditionally if `alias_of` found in edge-attrs.
@@ -1263,6 +1265,10 @@ def _make_edge(self, plot_args: PlotArgs) -> pydot.Edge:
         styles = self._new_styles_stack(plot_args)
 
         styles.add("kw_edge")
+        if isinstance(src, Operation):
+            styles.add("kw_edge_tail_op")
+        if isinstance(dst, Operation):
+            styles.add("kw_edge_head_op")
         if edge_attrs.get("optional"):
             styles.add("kw_edge_optional")
         if edge_attrs.get("sideffect"):

test/test_plot.py

@@ -562,10 +562,10 @@ def test_node_dot_str0(dot_str_pipeline):
                 ><B>FN:</B> test.test_plot.func</TD>
             </TR>
         </TABLE>>, shape=plain, tooltip=<cu:sto:m>];
-        <edge> -> <node>  [headport=n, tailport=s];
-        <edge> -> <cu&#58;sto&#58;m>  [headport=n, tailport=s];
-        <digraph&#58; strict> -> <node>  [headport=n, tailport=s];
-        <digraph&#58; strict> -> <cu&#58;sto&#58;m>  [headport=n, tailport=s];
+        <edge> -> <node>  [arrowtail=dot, dir=both, headport=n, tailport=s];
+        <edge> -> <cu&#58;sto&#58;m>  [arrowtail=dot, dir=both, headport=n, tailport=s];
+        <digraph&#58; strict> -> <node>  [arrowtail=dot, dir=both, headport=n, tailport=s];
+        <digraph&#58; strict> -> <cu&#58;sto&#58;m>  [arrowtail=dot, dir=both, headport=n, tailport=s];
         <node> -> <&lt;graph&gt;>  [headport=n, tailport=s];
         <cu&#58;sto&#58;m> -> <&lt;graph&gt;>  [headport=n, tailport=s];
         legend [URL="https://graphtik.readthedocs.io/en/latest/_images/GraphtikLegend.svg", fillcolor=yellow, shape=component, style=filled, target=_blank];
@@ -607,8 +607,8 @@ def test_node_dot_str1(dot_str_pipeline, monkeypatch):
         </TABLE>>, shape=plain, tooltip=<cu:sto:m>];
         }
 
-        <edge> -> <cu&#58;sto&#58;m>  [headport=n, tailport=s];
-        <digraph&#58; strict> -> <cu&#58;sto&#58;m>  [headport=n, tailport=s];
+        <edge> -> <cu&#58;sto&#58;m>  [arrowtail=dot, dir=both, headport=n, tailport=s];
+        <digraph&#58; strict> -> <cu&#58;sto&#58;m>  [arrowtail=dot, dir=both, headport=n, tailport=s];
         <cu&#58;sto&#58;m> -> <&lt;graph&gt;>  [headport=n, tailport=s];
         legend [URL="https://graphtik.readthedocs.io/en/latest/_images/GraphtikLegend.svg", fillcolor=yellow, shape=component, style=filled, target=_blank];
         }