diff -r f99d60d6b59b -r 2602857055c5 eric6/Graphics/GraphicsUtilities.py
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/eric6/Graphics/GraphicsUtilities.py Sun Apr 14 15:09:21 2019 +0200
@@ -0,0 +1,114 @@
+# -*- coding: utf-8 -*-
+
+# Copyright (c) 2004 - 2019 Detlev Offenbach <detlev@die-offenbachs.de>
+#
+
+"""
+Module implementing some graphical utility functions.
+"""
+
+
+from __future__ import unicode_literals
+
+
+class RecursionError(OverflowError, ValueError):
+ """
+ Unable to calculate result because of recursive structure.
+ """
+ pass
+
+
+def sort(nodes, routes, noRecursion=False):
+ """
+ Function to sort widgets topographically.
+
+ Passed a list of nodes and a list of source, dest routes, it attempts
+ to create a list of stages, where each sub list is one stage in a process.
+
+ The algorithm was taken from Boa Constructor.
+
+ @param nodes list of nodes to be sorted
+ @param routes list of routes between the nodes
+ @param noRecursion flag indicating, if recursion errors should be raised
+ @exception RecursionError a recursion error was detected
+ @return list of stages
+ """
+ children, parents = _buildChildrenLists(routes)
+
+ # first stage is those nodes having no incoming routes...
+ stage = []
+ stages = [stage]
+ taken = []
+ for node in nodes:
+ if not parents.get(node):
+ stage.append(node)
+
+ if nodes and not stage:
+ # there is no element, which does not depend on some other element!
+ stage.append(nodes[0])
+
+ taken.extend(stage)
+ nodes = list(filter(lambda x, li=stage: x not in li, nodes))
+ while nodes:
+ previousStageChildren = []
+ nodelen = len(nodes)
+
+ # second stage are those nodes, which are direct children of the
+ # first stage
+ for node in stage:
+ for child in children.get(node, []):
+ if child not in previousStageChildren and child not in taken:
+ previousStageChildren.append(child)
+ elif child in taken and noRecursion:
+ raise RecursionError((child, node))
+
+ # unless they are children of other direct children...
+ stage = previousStageChildren
+ removes = []
+ for current in stage:
+ currentParents = parents.get(current, [])
+ for parent in currentParents:
+ if parent in stage and parent != current:
+ # might wind up removing current
+ if current not in parents.get(parent, []):
+ # is not mutually dependant
+ removes.append(current)
+
+ for remove in removes:
+ while remove in stage:
+ stage.remove(remove)
+
+ stages.append(stage)
+ taken.extend(stage)
+ nodes = list(filter(lambda x, li=stage: x not in li, nodes))
+ if nodelen == len(nodes):
+ if noRecursion:
+ raise RecursionError(nodes)
+ else:
+ stages.append(nodes[:])
+ nodes = []
+
+ return stages
+
+
+def _buildChildrenLists(routes):
+ """
+ Function to build up parent - child relationships.
+
+ Taken from Boa Constructor.
+
+ @param routes list of routes between nodes
+ @return dictionary of child and dictionary of parent relationships
+ """
+ childrenTable = {}
+ parentTable = {}
+ for sourceID, destinationID in routes:
+ currentChildren = childrenTable.get(sourceID, [])
+ currentParents = parentTable.get(destinationID, [])
+ if destinationID not in currentChildren:
+ currentChildren.append(destinationID)
+ if sourceID not in currentParents:
+ currentParents.append(sourceID)
+ childrenTable[sourceID] = currentChildren
+ parentTable[destinationID] = currentParents
+ return childrenTable, parentTable
