api.unassign_representation_styles

src/ifcopenshell-python/ifcopenshell/api/style/unassign_representation_styles.py

@@ -0,0 +1,87 @@
+# IfcOpenShell - IFC toolkit and geometry engine
+# Copyright (C) 2021 Dion Moult <dion@thinkmoult.com>
+#
+# This file is part of IfcOpenShell.
+#
+# IfcOpenShell 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.
+#
+# IfcOpenShell 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 IfcOpenShell.  If not, see <http://www.gnu.org/licenses/>.
+
+
+class Usecase:
+    def __init__(self, file, shape_representation=None, styles=None, should_use_presentation_style_assignment=False):
+        """Unassigns styles directly assigned to an object representation
+
+        This does the inverse of assign_representation_styles.
+
+        :param shape_representation: The IfcShapeRepresentation of the object
+            that you want to unassign styles from.
+        :type shape_representation: ifcopenshell.entity_instance.entity_instance
+        :param styles: A list of presentation styles, typically IfcSurfaceStyle.
+            The number of items in the list should correlate with the number of
+            items in the shape_representation's Items attribute. If you have
+            more items than styles, the last style is used.
+        :type styles: list[ifcopenshell.entity_instance.entity_instance]
+        :param should_use_presentation_style_assignment: This is a technical
+            detail to accomodate a bug in Revit. This should always be left as
+            the default of False, unless you are finding that colours aren't
+            showing up in Revit. In that case, set it to True, but keep in mind
+            that this is no longer a valid IFC. Blame Autodesk.
+        :type should_use_presentation_style_assignment: bool
+        :return: None
+        :rtype: None
+
+        Example:
+
+        .. code:: python
+
+            ifcopenshell.api.run("style.unassign_representation_styles", model,
+                shape_representation=representation, styles=[style])
+        """
+        self.file = file
+        self.settings = {
+            "shape_representation": shape_representation,
+            "styles": styles or [],
+            "should_use_presentation_style_assignment": should_use_presentation_style_assignment,
+        }
+
+    def execute(self):
+        if not self.settings["styles"]:
+            return []
+        self.results = []
+        use_style_assignment = self.file.schema == "IFC2X3" or self.settings["should_use_presentation_style_assignment"]
+
+        for element in self.file.traverse(self.settings["shape_representation"]):
+            if not element.is_a("IfcShapeRepresentation"):
+                continue
+            for item in element.Items:
+                if not item.is_a("IfcGeometricRepresentationItem"):
+                    continue
+
+                if not item.StyledByItem:
+                    continue
+
+                item = item.StyledByItem[0]
+                if use_style_assignment:
+                    for style_ in item.Styles:
+                        if style_.is_a("IfcPresentationStyleAssignment"):
+                            self.remove_styles(style_)
+                self.remove_styles(item)
+
+    def remove_styles(self, item):
+        """Removes styles from a styled item or a style assignment
+        and purges item if doesn't have any styles after"""
+        styles = [s for s in item.Styles if s not in self.settings["styles"]]
+        if not styles:
+            self.file.remove(item)
+        elif len(styles) != len(item.Styles):
+            item.Styles = styles

src/ifcopenshell-python/test/api/style/test_unassign_representation_styles.py

@@ -0,0 +1,111 @@
+# IfcOpenShell - IFC toolkit and geometry engine
+# Copyright (C) 2022 Dion Moult <dion@thinkmoult.com>
+#
+# This file is part of IfcOpenShell.
+#
+# IfcOpenShell 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.
+#
+# IfcOpenShell 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 IfcOpenShell.  If not, see <http://www.gnu.org/licenses/>.
+
+import pytest
+import test.bootstrap
+import ifcopenshell
+import ifcopenshell.api
+
+
+class TestUnassignRepresentationStyles(test.bootstrap.IFC4):
+    def test_run(self):
+        element = ifcopenshell.api.run("root.create_entity", self.file, ifc_class="IfcWall")
+        product_shape = self.file.createIfcProductDefinitionShape()
+        element.Representation = product_shape
+
+        representation = self.file.createIfcShapeRepresentation()
+        item = self.file.createIfcExtrudedAreaSolid()
+        representation.Items = [item]
+
+        style = self.file.createIfcSurfaceStyle()
+        ifcopenshell.api.run(
+            "style.assign_representation_styles", self.file, styles=[style], shape_representation=representation
+        )
+        style2 = self.file.createIfcSurfaceStyle()
+        ifcopenshell.api.run(
+            "style.assign_representation_styles", self.file, styles=[style2], shape_representation=representation
+        )
+        assert item.StyledByItem[0].Styles == (style, style2)
+
+        ifcopenshell.api.run(
+            "style.unassign_representation_styles", self.file, styles=[style], shape_representation=representation
+        )
+        assert item.StyledByItem[0].Styles == (style2,)
+
+        # unassigning last style removes styled item
+        ifcopenshell.api.run(
+            "style.unassign_representation_styles", self.file, styles=[style2], shape_representation=representation
+        )
+        assert len(item.StyledByItem) == 0
+        assert len(self.file.by_type("IfcStyledItem")) == 0
+
+    def test_assign_using_style_assignment(self):
+        element = ifcopenshell.api.run("root.create_entity", self.file, ifc_class="IfcWall")
+        product_shape = self.file.createIfcProductDefinitionShape()
+        element.Representation = product_shape
+
+        representation = self.file.createIfcShapeRepresentation()
+        item = self.file.createIfcExtrudedAreaSolid()
+        representation.Items = [item]
+
+        style = self.file.createIfcSurfaceStyle()
+        ifcopenshell.api.run(
+            "style.assign_representation_styles",
+            self.file,
+            styles=[style],
+            shape_representation=representation,
+            should_use_presentation_style_assignment=True,
+        )
+        style_assignment = self.file.by_type("IfcPresentationStyleAssignment")[0]
+
+        # reusing existing styled item and style assignment
+        style2 = self.file.createIfcSurfaceStyle()
+        ifcopenshell.api.run(
+            "style.assign_representation_styles",
+            self.file,
+            styles=[style2],
+            shape_representation=representation,
+            should_use_presentation_style_assignment=True,
+        )
+        assert style_assignment.Styles == (style, style2)
+
+        ifcopenshell.api.run(
+            "style.unassign_representation_styles",
+            self.file,
+            styles=[style],
+            shape_representation=representation,
+            should_use_presentation_style_assignment=True,
+        )
+        assert style_assignment.Styles == (style2,)
+
+        # unassigning last style removes styled item and presentation style
+        ifcopenshell.api.run(
+            "style.unassign_representation_styles",
+            self.file,
+            styles=[style2],
+            shape_representation=representation,
+            should_use_presentation_style_assignment=True,
+        )
+        assert len(item.StyledByItem) == 0
+        assert len(self.file.by_type("IfcStyledItem")) == 0
+        assert len(self.file.by_type("IfcPresentationStyleAssignment")) == 0
+
+
+class TestUnassignRepresentationStylesIFC2X3(test.bootstrap.IFC2X3):
+    def test_run(self):
+        TestUnassignRepresentationStyles.test_assign_using_style_assignment(self)