feat(pm4py): SVG position parser utility (replacing text-based parsin…

…g in Graphviz BPMN-based layout)

pm4py/objects/bpmn/layout/variants/graphviz.py

@@ -6,6 +6,7 @@
 from pm4py.objects.bpmn.obj import BPMN
 from pm4py.objects.bpmn.util.sorting import get_sorted_nodes_edges
 from pm4py.util import exec_utils
+from pm4py.visualization.common import svg_pos_parser
 import tempfile
 
 
@@ -109,21 +110,18 @@ def apply(bpmn_graph, parameters=None):
 
     gsave.save(viz, filename_svg.name)
 
-    nodes_pos = {}
+    nodes_p, edges_p = svg_pos_parser.apply(filename_svg.name)
 
-    content = open(filename_svg.name, "r").read()
-    viz_nodes = content.split("class=\"node\">")[1:]
-    for node in viz_nodes:
-        this_id = node.split("<title>")[1].split("</title>")[0]
-        points = node.split("points=\"")[1].split("\"")[0]
-        nodes_pos[inv_nodes_dict[this_id]] = points
+    nodes_pos = {}
+    for node in nodes_p:
+        nodes_pos[inv_nodes_dict[node]] = nodes_p[node]["polygon"]
 
     endpoints_wh = exec_utils.get_param_value(Parameters.TASK_WH, parameters, 30)
     task_wh = exec_utils.get_param_value(Parameters.TASK_WH, parameters, 60)
 
     # add node positions to BPMN nodes
     for n in graph_nodes:
-        node_pos = nodes_pos[n].split(" ")[0].split(",")
+        node_pos = nodes_pos[n][0]
 
         pos_x = float(node_pos[0])
         pos_y = float(node_pos[1])

pm4py/visualization/common/svg_pos_parser.py

@@ -0,0 +1,39 @@
+import xml.etree.ElementTree as ET
+from typing import Dict, Any, Tuple
+
+
+def apply(file_name: str) -> Tuple[Dict[str, Any], Dict[str, Any]]:
+    tree = ET.parse(file_name)
+    root = tree.getroot()
+    nodes = {}
+    edges = {}
+    for child in root:
+        for child2 in child:
+            this_class = child2.get("class")
+            if this_class in ["node", "edge"]:
+                title = None
+                label_x = None
+                label_y = None
+                label_text = None
+                polygon = None
+                for child3 in child2:
+                    if child3.tag.endswith("title"):
+                        title = child3.text
+                    elif child3.tag.endswith("text"):
+                        label_x = child3.get("x")
+                        label_y = child3.get("y")
+                        label_text = child3.text
+                    elif child3.tag.endswith("polygon"):
+                        polygon = child3.get("points").split(" ")
+                        polygon = [x.split(",") for x in polygon]
+                        polygon = tuple((float(x[0]), float(x[1])) for x in polygon)
+                if this_class == "node":
+                    nodes[title] = {"label": label_text, "label_x": label_x, "label_y": label_y, "polygon": polygon}
+                elif this_class == "edge":
+                    title = title.replace("->", " ").strip()
+                    these_nodes = tuple(title.split(" "))
+                    if these_nodes[0] in nodes and these_nodes[1] in nodes:
+                        edges[these_nodes] = {"label": label_text, "label_x": label_x, "label_y": label_y,
+                                              "polygon": polygon}
+
+    return nodes, edges