Add PoC visualisation [WIP]

It almost works… meaning it manages to segfault.

poor_mans_visualisation.py

@@ -0,0 +1,63 @@
+#!/usr/bin/env python3
+
+# Get topologies
+
+import sys
+from birdvisu import maps_new
+from birdvisu.maps_new import providers
+
+ref_topo_file = 'reference.ospf'
+if len(sys.argv) > 1:
+	ref_topo_file = sys.argv[1]
+
+with open(ref_topo_file) as ref_file:
+	ref_topo = providers.OspfFileTopologyProvider(ref_file).get_topology()
+
+cur_topo = providers.RunningBirdTopologyProvider().get_topology()
+
+# Combine topologies
+
+combiner = maps_new.TopologyCombiner()
+# NOTE: the following string literals convey meaning for annotators, so they
+# should not be changed carelessly.
+combiner.add_topology('reference', ref_topo)
+combiner.add_topology('actual', cur_topo)
+
+final_topo = combiner.get_complete_topology()
+
+# Annotate it
+
+from birdvisu.visualisation import annotators
+
+annotated_topology = maps_new.annotate_topology(final_topo,
+			# A semi-canonical set of annotators:
+			[
+				annotators.difference_annotator,
+				annotators.extract_positions,
+				annotators.random_position,
+				annotators.assign_brushes,
+				annotators.create_qgritems,
+				]
+			)
+
+# Render the widget
+
+from PySide6 import QtCore, QtGui, QtWidgets
+
+app = QtWidgets.QApplication([])
+scene = QtWidgets.QGraphicsScene()
+
+for tagsrc in [
+		annotated_topology.router_annotations.values(),
+		annotated_topology.network_annotations.values(),
+		annotated_topology.link_annotations.values(),
+		]:
+	for taglist in tagsrc:
+		assert len(taglist) > 0
+		assert isinstance(taglist[-1], QtWidgets.QGraphicsItem)
+		scene.addItem(taglist[-1])
+
+view = QtWidgets.QGraphicsView(scene)
+view.show()
+
+app.exec()