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comparison dwtx/draw2d/graph/LocalOptimizer.d @ 98:95307ad235d9

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Added Draw2d code, still work in progress
author Frank Benoit <benoit@tionex.de>
date Sun, 03 Aug 2008 00:52:14 +0200
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96:b492ba44e44d 98:95307ad235d9
1 /*******************************************************************************
2 * Copyright (c) 2003, 2005 IBM Corporation and others.
3 * All rights reserved. This program and the accompanying materials
4 * are made available under the terms of the Eclipse Public License v1.0
5 * which accompanies this distribution, and is available at
6 * http://www.eclipse.org/legal/epl-v10.html
7 *
8 * Contributors:
9 * IBM Corporation - initial API and implementation
10 * Port to the D programming language:
11 * Frank Benoit <benoit@tionex.de>
12 *******************************************************************************/
13 module dwtx.draw2d.graph.LocalOptimizer;
14
15 import dwt.dwthelper.utils;
16 import dwtx.draw2d.graph.GraphVisitor;
17 import dwtx.draw2d.graph.GraphUtilities;
18 import dwtx.draw2d.graph.Node;
19 import dwtx.draw2d.graph.Rank;
20 import dwtx.draw2d.graph.DirectedGraph;
21 import dwtx.draw2d.graph.EdgeList;
22 import dwtx.draw2d.graph.Edge;
23
24 /**
25 * This graph visitor examines all adjacent pairs of nodes and determines if
26 * swapping the two nodes provides improved graph aesthetics.
27 * @author Daniel Lee
28 * @since 2.1.2
29 */
30 class LocalOptimizer : GraphVisitor {
31
32 bool shouldSwap(Node current, Node next) {
33 if (GraphUtilities.isConstrained(current, next))
34 return false;
35 int crossCount = 0;
36 int invertedCrossCount = 0;
37
38 EdgeList currentEdges = current.incoming;
39 EdgeList nextEdges = next.incoming;
40 int rank = current.rank - 1;
41 int iCurrent, iNext;
42
43 for (int i = 0; i < currentEdges.size(); i++) {
44 Edge currentEdge = currentEdges.getEdge(i);
45 iCurrent = currentEdge.getIndexForRank(rank);
46 for (int j = 0; j < nextEdges.size(); j++) {
47 iNext = nextEdges.getEdge(j).getIndexForRank(rank);
48 if (iNext < iCurrent)
49 crossCount++;
50 else if (iNext > iCurrent)
51 invertedCrossCount++;
52 else {
53 //edges go to the same location
54 int offsetDiff = nextEdges.getEdge(j).getSourceOffset()
55 - currentEdge.getSourceOffset();
56 if (offsetDiff < 0)
57 crossCount++;
58 else if (offsetDiff > 0)
59 invertedCrossCount++;
60 }
61 }
62 }
63
64 currentEdges = current.outgoing;
65 nextEdges = next.outgoing;
66 rank = current.rank + 1;
67
68 for (int i = 0; i < currentEdges.size(); i++) {
69 Edge currentEdge = currentEdges.getEdge(i);
70 iCurrent = currentEdge.getIndexForRank(rank);
71 for (int j = 0; j < nextEdges.size(); j++) {
72 iNext = nextEdges.getEdge(j).getIndexForRank(rank);
73 if (iNext < iCurrent)
74 crossCount++;
75 else if (iNext > iCurrent)
76 invertedCrossCount++;
77 else {
78 //edges go to the same location
79 int offsetDiff = nextEdges.getEdge(j).getTargetOffset()
80 - currentEdge.getTargetOffset();
81 if (offsetDiff < 0)
82 crossCount++;
83 else if (offsetDiff > 0)
84 invertedCrossCount++;
85 }
86 }
87 }
88 if (invertedCrossCount < crossCount)
89 return true;
90 return false;
91 }
92
93 private void swapNodes(Node current, Node next, Rank rank) {
94 int index = rank.indexOf(current);
95 rank.set(index + 1, current);
96 rank.set(index, next);
97 index = current.index;
98 current.index = next.index;
99 next.index = index;
100 }
101
102 /**
103 * @see GraphVisitor#visit(dwtx.draw2d.graph.DirectedGraph)
104 */
105 public void visit(DirectedGraph g) {
106 bool flag;
107 do {
108 flag = false;
109 for (int r = 0; r < g.ranks.size(); r++) {
110 Rank rank = g.ranks.getRank(r);
111 for (int n = 0; n < rank.count() - 1; n++) {
112 Node currentNode = rank.getNode(n);
113 Node nextNode = rank.getNode(n + 1);
114 if (shouldSwap(currentNode, nextNode)) {
115 swapNodes(currentNode, nextNode, rank);
116 flag = true;
117 n = Math.max(0, n - 2);
118 }
119 }
120 }
121 } while (flag);
122 }
123
124 }