signalflow_visualisation: Add support for visualising patch structure

auxiliary/libs/signalflow_visualisation/__init__.py

@@ -0,0 +1,80 @@
+import json
+import networkx as nx
+from IPython.display import SVG
+from signalflow import Patch
+
+def visualise_patch_structure(patch: Patch):
+    """
+    Renders the structure of a patch as a directed graph.
+
+    Requires:
+     - networkx
+     - pygraphviz (https://github.com/pygraphviz/pygraphviz/issues/11)
+
+    Args:
+        patch (Patch): The patch to diagram.
+
+    Returns:
+        An IPython SVG object that can be rendered in a notebook.
+
+    TODO: Implement support for cyclical graphs (requires reformulating JSON using JSON pointers)
+    """
+
+    G = nx.DiGraph()
+
+    def label_map(label):
+        lookup = {
+            "add": "+",
+            "multiply": "×",
+            "subtract": "-",
+            "divide": "÷"
+        }
+        if label in lookup.keys():
+            return lookup[label]
+        else:
+            return label
+
+    spec = patch.to_spec()
+    structure = json.loads(spec.to_json())
+    nodes = structure["nodes"]
+    for node in nodes:
+        node_label = node["node"]
+        node_label = label_map(node_label)
+        node_label = "<b>%s</b>" % node_label
+
+        node_label += "<font point-size='8'><br />"
+        for input_key, input_value in node["inputs"].items():
+            if not isinstance(input_value, dict):
+                node_label += "<br /><font point-size='2'><br /></font>%s = %s" % (input_key, round(input_value, 7))
+        node_label += "</font>"
+
+        # special graphviz syntax for enabling HTML formatting in node labels
+        node_label = "<%s>" % node_label
+        G.add_node(node["id"], label=node_label)
+    for node in nodes:
+        for input_key, input_value in node["inputs"].items():
+            if isinstance(input_value, dict):
+                label = ""
+                if not input_key.startswith("input"):
+                    label = input_key
+                    # white background
+                    # label = "<<table border='0' cellborder='0' cellspacing='0'><tr><td bgcolor='white'>%s</td></tr></table>>" % label
+                G.add_edge(input_value["id"], node["id"], label=label)
+
+    ag = nx.nx_agraph.to_agraph(G)
+    ag.graph_attr["splines"] = "polyline"
+    ag.node_attr["penwidth"] = 0.5
+    ag.node_attr["fontname"] = "helvetica"
+    ag.node_attr["fontsize"] = 9
+    ag.node_attr["margin"] = 0.12
+    ag.node_attr["height"] = 0.3
+    ag.edge_attr["fontname"] = "helvetica"
+    ag.edge_attr["fontsize"] = 8
+    ag.edge_attr["penwidth"] = 0.5
+    ag.edge_attr["arrowsize"] = 0.5
+    ag.edge_attr["labelfloat"] = False
+    ag.edge_attr["labeldistance"] = 0
+    ag.node_attr["shape"] = "rectangle"
+    ag.layout(prog='dot')
+    svg = ag.draw(format='svg')
+    return SVG(svg)

setup.py

@@ -49,7 +49,12 @@ def build_extension(self, ext):
             shutil.copy(os.path.join(self.build_temp, cfg, libname), "auxiliary/libs/signalflow")
 
 
-signalflow_packages = ['signalflow_midi', 'signalflow-stubs', 'signalflow_examples']
+signalflow_packages = [
+    'signalflow-stubs',
+    'signalflow_midi',
+    'signalflow_examples',
+    'signalflow_visualisation'
+]
 signalflow_package_data = []
 if sys.platform == 'win32':
     # --------------------------------------------------------------------------------