New IfcPatch recipe to merge identical styles

src/ifcpatch/ifcpatch/recipes/MergeStyles.py

@@ -0,0 +1,52 @@
+# IfcPatch - IFC patching utiliy
+# Copyright (C) 2023 Dion Moult <dion@thinkmoult.com>
+#
+# This file is part of IfcPatch.
+#
+# IfcPatch is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# IfcPatch is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with IfcPatch.  If not, see <http://www.gnu.org/licenses/>.
+
+import ifcopenshell
+import ifcopenshell.guid
+
+
+class Patcher:
+    def __init__(self, file, logger):
+        """Merge identical styles together
+
+        Some software may create an obscene number of styles instead of reusing
+        them properly. This patch merges all IfcPresentationStyle,
+        IfcSurfaceStyleShading, and IfcColourRgb if they are identical.
+
+        Example:
+
+        .. code:: python
+
+            ifcpatch.execute({"file": model, "recipe": "MergeStyles", "arguments": []})
+        """
+        self.file = file
+        self.logger = logger
+
+    def patch(self):
+        for ifc_class in ("IfcColourRgb", "IfcSurfaceStyleShading", "IfcPresentationStyle"):
+            uniques = {}
+            i = 0
+            for element in self.file.by_type(ifc_class):
+                data = "-".join([str(a) for a in element])
+                if (unique := uniques.get(data, None)):
+                    ifcopenshell.util.element.replace_element(element, unique)
+                    self.file.remove(element)
+                    i += 1
+                else:
+                    uniques[data] = element
+            print(f"Replaced {i} {ifc_class}")