tightening up deletion logic for group nodes.

Author: jchanvfx

NodeGraphQt/base/factory.py

@@ -56,9 +56,8 @@ def create_node_instance(self, node_type=None):
             node_type = self.aliases[node_type]
 
         _NodeClass = self.__nodes.get(node_type)
-        if not _NodeClass:
-            print('can\'t find node type {}'.format(node_type))
-        return _NodeClass()
+        if _NodeClass:
+            return _NodeClass()
 
     def register_node(self, node, alias=None):
         """

NodeGraphQt/base/graph.py

@@ -24,6 +24,7 @@
     PortTypeEnum,
     ViewerEnum
 )
+from NodeGraphQt.errors import NodeCreationError, NodeDeletionError
 from NodeGraphQt.nodes.backdrop_node import BackdropNode
 from NodeGraphQt.nodes.base_node import BaseNode
 from NodeGraphQt.nodes.group_node import GroupNode
@@ -1123,7 +1124,7 @@ def format_color(clr):
 
             self.node_created.emit(node)
             return node
-        raise TypeError('\n\n>> Cannot find node:\t"{}"\n'.format(node_type))
+        raise NodeCreationError('Can\'t find node: "{}"'.format(node_type))
 
     def add_node(self, node, pos=None, selected=True, push_undo=True):
         """
@@ -1198,6 +1199,10 @@ def delete_node(self, node, push_undo=True):
                                  push_undo=push_undo)
                 p.clear_connections()
 
+        # collapse group node before removing.
+        if isinstance(node, GroupNode) and node.is_expanded:
+            node.collapse()
+
         if push_undo:
             self._undo_stack.push(NodeRemovedCmd(self, node))
             self._undo_stack.endMacro()
@@ -1223,6 +1228,10 @@ def remove_node(self, node, push_undo=True):
         if push_undo:
             self._undo_stack.beginMacro('delete node: "{}"'.format(node.name()))
 
+        # collapse group node before removing.
+        if isinstance(node, GroupNode) and node.is_expanded:
+            node.collapse()
+
         if isinstance(node, BaseNode):
             for p in node.input_ports():
                 if p.locked():
@@ -1260,6 +1269,11 @@ def delete_nodes(self, nodes, push_undo=True):
         if push_undo:
             self._undo_stack.beginMacro('deleted "{}" nodes'.format(len(nodes)))
         for node in nodes:
+
+            # collapse group node before removing.
+            if isinstance(node, GroupNode) and node.is_expanded:
+                node.collapse()
+
             if isinstance(node, BaseNode):
                 for p in node.input_ports():
                     if p.locked():
@@ -2472,12 +2486,34 @@ def delete_node(self, node, push_undo=True):
         if node in port_nodes and node.parent_port is not None:
             # note: port nodes can only be deleted by deleting the parent
             #       port object.
-            raise RuntimeError(
-                'Can\'t delete node "{}" it is attached to port "{}"'
-                .format(node, node.parent_port)
+            raise NodeDeletionError(
+                '{} can\'t be deleted as it is attached to a port!'.format(node)
             )
         super(SubGraph, self).delete_node(node, push_undo=push_undo)
 
+    def delete_nodes(self, nodes, push_undo=True):
+        """
+        Remove a list of specified nodes from the node graph.
+
+        Args:
+            nodes (list[NodeGraphQt.BaseNode]): list of node instances.
+            push_undo (bool): register the command to the undo stack. (default: True)
+        """
+        if not nodes:
+            return
+
+        port_nodes = self.get_input_port_nodes() + self.get_output_port_nodes()
+        for node in nodes:
+            if node in port_nodes and node.parent_port is not None:
+                # note: port nodes can only be deleted by deleting the parent
+                #       port object.
+                raise NodeDeletionError(
+                    '{} can\'t be deleted as it is attached to a port!'
+                    .format(node)
+                )
+
+        super(SubGraph, self).delete_nodes(nodes, push_undo=push_undo)
+
     def collapse_graph(self, clear_session=True):
         """
         Collapse the current sub graph and hide its widget.

NodeGraphQt/errors.py

@@ -11,6 +11,12 @@ class NodePropertyError(Exception): pass
 class NodeWidgetError(Exception): pass
 
 
+class NodeCreationError(Exception): pass
+
+
+class NodeDeletionError(Exception): pass
+
+
 class NodeRegistrationError(Exception): pass
 
 

NodeGraphQt/widgets/dialogs.py

@@ -48,7 +48,7 @@ def message_dialog(text='', title='Message'):
         dlg.setWindowTitle(title)
         dlg.setInformativeText(text)
         dlg.setStandardButtons(QtWidgets.QMessageBox.Ok)
-        return dlg.exec_()
+        dlg.exec_()
 
     @staticmethod
     def question_dialog(text='', title='Are you sure?'):

examples/basic_example.py

@@ -97,7 +97,8 @@
     n_backdrop = graph.create_node('Backdrop')
     n_backdrop.wrap_nodes([n_custom_ports, n_combo_menu])
 
-    # fit node selection to the viewer.
+    # fit nodes to the viewer.
+    graph.clear_selection()
     graph.fit_to_selection()
 
     # Custom builtin widgets from NodeGraphQt