public class GraphPanel extends JComponent
1: import java.awt.*;
2: import java.awt.geom.*;
3: import java.awt.event.*;
4: import javax.swing.*;
5: import javax.swing.event.*;
7: /**
8: A panel to draw a graph
9: */
10: public class GraphPanel extends JComponent
11: {
12: /**
13: Constructs a graph panel.
14: @param aToolBar the tool bar with the node and edge tools
15: @param aGraph the graph to be displayed and edited
16: */
17: public GraphPanel(ToolBar aToolBar, Graph aGraph)
18: {
19: toolBar = aToolBar;
20: graph = aGraph;
21: setBackground(Color.WHITE);
23: addMouseListener(new
24: MouseAdapter()
25: {
26: public void mousePressed(MouseEvent event)
27: {
28: Point2D mousePoint = event.getPoint();
29: Node n = graph.findNode(mousePoint);
30: Edge e = graph.findEdge(mousePoint);
31: Object tool = toolBar.getSelectedTool();
32: if (tool == null) // select
33: {
34: if (e != null)
35: {
36: selected = e;
37: }
38: else if (n != null)
39: {
40: selected = n;
41: dragStartPoint = mousePoint;
42: dragStartBounds = n.getBounds();
43: }
44: else
45: {
46: selected = null;
47: }
48: }
49: else if (tool instanceof Node)
50: {
51: Node prototype = (Node) tool;
52: Node newNode = (Node) prototype.clone();
53: boolean added = graph.add(newNode, mousePoint);
54: if (added)
55: {
56: selected = newNode;
57: dragStartPoint = mousePoint;
58: dragStartBounds = newNode.getBounds();
59: }
60: else if (n != null)
61: {
62: selected = n;
63: dragStartPoint = mousePoint;
64: dragStartBounds = n.getBounds();
65: }
66: }
67: else if (tool instanceof Edge)
68: {
69: if (n != null) rubberBandStart = mousePoint;
70: }
71: lastMousePoint = mousePoint;
72: repaint();
73: }
75: public void mouseReleased(MouseEvent event)
76: {
77: Object tool = toolBar.getSelectedTool();
78: if (rubberBandStart != null)
79: {
80: Point2D mousePoint = event.getPoint();
81: Edge prototype = (Edge) tool;
82: Edge newEdge = (Edge) prototype.clone();
83: if (graph.connect(newEdge,
84: rubberBandStart, mousePoint))
85: selected = newEdge;
86: }
88: validate();
89: repaint();
91: lastMousePoint = null;
92: dragStartBounds = null;
93: rubberBandStart = null;
94: }
95: });
97: addMouseMotionListener(new
98: MouseMotionAdapter()
99: {
100: public void mouseDragged(MouseEvent event)
101: {
102: Point2D mousePoint = event.getPoint();
103: if (dragStartBounds != null)
104: {
105: if (selected instanceof Node)
106: {
107: Node n = (Node) selected;
108: Rectangle2D bounds = n.getBounds();
109: n.translate(
110: dragStartBounds.getX() - bounds.getX()
111: + mousePoint.getX() - dragStartPoint.getX(),
112: dragStartBounds.getY() - bounds.getY()
113: + mousePoint.getY() - dragStartPoint.getY());
114: }
115: }
116: lastMousePoint = mousePoint;
117: repaint();
118: }
119: });
120: }
122: public void paintComponent(Graphics g)
123: {
124: Graphics2D g2 = (Graphics2D) g;
125: Rectangle2D bounds = getBounds();
126: Rectangle2D graphBounds = graph.getBounds(g2);
127: graph.draw(g2);
129: if (selected instanceof Node)
130: {
131: Rectangle2D grabberBounds = ((Node) selected).getBounds();
132: drawGrabber(g2, grabberBounds.getMinX(), grabberBounds.getMinY());
133: drawGrabber(g2, grabberBounds.getMinX(), grabberBounds.getMaxY());
134: drawGrabber(g2, grabberBounds.getMaxX(), grabberBounds.getMinY());
135: drawGrabber(g2, grabberBounds.getMaxX(), grabberBounds.getMaxY());
136: }
138: if (selected instanceof Edge)
139: {
140: Line2D line = ((Edge) selected).getConnectionPoints();
141: drawGrabber(g2, line.getX1(), line.getY1());
142: drawGrabber(g2, line.getX2(), line.getY2());
143: }
145: if (rubberBandStart != null)
146: {
147: Color oldColor = g2.getColor();
148: g2.setColor(PURPLE);
149: g2.draw(new Line2D.Double(rubberBandStart, lastMousePoint));
150: g2.setColor(oldColor);
151: }
152: }
155: /**
156: Removes the selected node or edge.
157: */
158: public void removeSelected()
159: {
160: if (selected instanceof Node)
161: {
162: graph.removeNode((Node) selected);
163: }
164: else if (selected instanceof Edge)
165: {
166: graph.removeEdge((Edge) selected);
167: }
168: selected = null;
169: repaint();
170: }
172: /**
173: Draws a single "grabber", a filled square
174: @param g2 the graphics context
175: @param x the x coordinate of the center of the grabber
176: @param y the y coordinate of the center of the grabber
177: */
178: public static void drawGrabber(Graphics2D g2, double x, double y)
179: {
180: final int SIZE = 5;
181: Color oldColor = g2.getColor();
182: g2.setColor(PURPLE);
183: g2.fill(new Rectangle2D.Double(x - SIZE / 2,
184: y - SIZE / 2, SIZE, SIZE));
185: g2.setColor(oldColor);
186: }
188: public Dimension getPreferredSize()
189: {
190: Rectangle2D bounds
191: = graph.getBounds((Graphics2D) getGraphics());
192: return new Dimension(
193: (int) bounds.getMaxX(),
194: (int) bounds.getMaxY());
195: }
197: private Graph graph;
198: private ToolBar toolBar;
199: private Point2D lastMousePoint;
200: private Point2D rubberBandStart;
201: private Point2D dragStartPoint;
202: private Rectangle2D dragStartBounds;
203: private Object selected;
204: private static final Color PURPLE = new Color(0.7f, 0.4f, 0.7f);
205: }