DragControl


1   package prefuse.controls;
2   
3   import java.awt.Cursor  ;
4   import java.awt.event.MouseEvent  ;
5   import java.awt.geom.Point2D  ;
6   
7   import javax.swing.SwingUtilities  ;
8   
9   import prefuse.Display;
10  import prefuse.data.Table;
11  import prefuse.data.event.EventConstants;
12  import prefuse.data.event.TableListener;
13  import prefuse.visual.VisualItem;
14  
15  
16  /**
17   * Changes a node's location when dragged on screen. Other effects
18   * include fixing a node's position when the mouse if over it, and
19   * changing the mouse cursor to a hand when the mouse passes over an
20   * item.
21   *
22   * @author <a HREF="http://jheer.org">jeffrey heer</a>
23   */
24  public class DragControl extends ControlAdapter implements TableListener {
25  
26      private VisualItem activeItem;
27      protected String   action;
28      protected Point2D   down = new Point2D.Double  ();
29      protected Point2D   temp = new Point2D.Double  ();
30      protected boolean dragged, wasFixed, resetItem;
31      private boolean fixOnMouseOver = true;
32      protected boolean repaint = true;
33      
34      /**
35       * Creates a new drag control that issues repaint requests as an item
36       * is dragged.
37       */
38      public DragControl() {
39      }
40      
41      /**
42       * Creates a new drag control that optionally issues repaint requests
43       * as an item is dragged.
44       * @param repaint indicates whether or not repaint requests are issued
45       *  as drag events occur. This can be set to false if other activities
46       *  (for example, a continuously running force simulation) are already
47       *  issuing repaint events.
48       */
49      public DragControl(boolean repaint) {
50          this.repaint = repaint;
51      }
52      
53      /**
54       * Creates a new drag control that optionally issues repaint requests
55       * as an item is dragged.
56       * @param repaint indicates whether or not repaint requests are issued
57       *  as drag events occur. This can be set to false if other activities
58       *  (for example, a continuously running force simulation) are already
59       *  issuing repaint events.
60       * @param fixOnMouseOver indicates if object positions should become
61       * fixed (made stationary) when the mouse pointer is over an item.
62       */
63      public DragControl(boolean repaint, boolean fixOnMouseOver) {
64          this.repaint = repaint;
65          this.fixOnMouseOver = fixOnMouseOver;
66      }
67      
68      /**
69       * Creates a new drag control that invokes an action upon drag events.
70       * @param action the action to run when drag events occur.
71       */
72      public DragControl(String   action) {
73          this.repaint = false;
74          this.action = action;
75      }
76      
77      /**
78       * Creates a new drag control that invokes an action upon drag events.
79       * @param action the action to run when drag events occur
80       * @param fixOnMouseOver indicates if object positions should become
81       * fixed (made stationary) when the mouse pointer is over an item.
82       */
83      public DragControl(String   action, boolean fixOnMouseOver) {
84          this.repaint = false;
85          this.fixOnMouseOver = fixOnMouseOver;
86          this.action = action;
87      }
88      
89      /**
90       * Determines whether or not an item should have it's position fixed
91       * when the mouse moves over it.
92       * @param s whether or not item position should become fixed upon
93       *  mouse over.
94       */
95      public void setFixPositionOnMouseOver(boolean s) {
96          fixOnMouseOver = s;
97      }
98      
99      /**
100      * @see prefuse.controls.Control#itemEntered(prefuse.visual.VisualItem, java.awt.event.MouseEvent)
101      */
102     public void itemEntered(VisualItem item, MouseEvent   e) {
103         Display d = (Display)e.getSource();
104         d.setCursor(Cursor.getPredefinedCursor(Cursor.HAND_CURSOR));
105         activeItem = item;
106         if ( fixOnMouseOver ) {
107             wasFixed = item.isFixed();
108             resetItem = true;
109             item.setFixed(true);
110             item.getTable().addTableListener(this);
111         }
112     }
113     
114     /**
115      * @see prefuse.controls.Control#itemExited(prefuse.visual.VisualItem, java.awt.event.MouseEvent)
116      */
117     public void itemExited(VisualItem item, MouseEvent   e) {
118         if ( activeItem == item ) {
119             activeItem = null;
120             item.getTable().removeTableListener(this);
121             if ( resetItem ) item.setFixed(wasFixed);
122         }
123         Display d = (Display)e.getSource();
124         d.setCursor(Cursor.getDefaultCursor());
125     } //
126     
127     /**
128      * @see prefuse.controls.Control#itemPressed(prefuse.visual.VisualItem, java.awt.event.MouseEvent)
129      */
130     public void itemPressed(VisualItem item, MouseEvent   e) {
131         if (!SwingUtilities.isLeftMouseButton(e)) return;
132         if ( !fixOnMouseOver ) {
133             wasFixed = item.isFixed();
134             resetItem = true;
135             item.setFixed(true);
136             item.getTable().addTableListener(this);
137         }
138         dragged = false;
139         Display d = (Display)e.getComponent();
140         d.getAbsoluteCoordinate(e.getPoint(), down);
141     }
142     
143     /**
144      * @see prefuse.controls.Control#itemReleased(prefuse.visual.VisualItem, java.awt.event.MouseEvent)
145      */
146     public void itemReleased(VisualItem item, MouseEvent   e) {
147         if (!SwingUtilities.isLeftMouseButton(e)) return;
148         if ( dragged ) {
149             activeItem = null;
150             item.getTable().removeTableListener(this);
151             if ( resetItem ) item.setFixed(wasFixed);
152             dragged = false;
153         }            
154     }
155     
156     /**
157      * @see prefuse.controls.Control#itemDragged(prefuse.visual.VisualItem, java.awt.event.MouseEvent)
158      */
159     public void itemDragged(VisualItem item, MouseEvent   e) {
160         if (!SwingUtilities.isLeftMouseButton(e)) return;
161         dragged = true;
162         Display d = (Display)e.getComponent();
163         d.getAbsoluteCoordinate(e.getPoint(), temp);
164         double dx = temp.getX()-down.getX();
165         double dy = temp.getY()-down.getY();
166         double x = item.getX();
167         double y = item.getY();
168 
169         item.setStartX(x);  item.setStartY(y);
170         item.setX(x+dx);    item.setY(y+dy);
171         item.setEndX(x+dx); item.setEndY(y+dy);
172         
173         if ( repaint )
174             item.getVisualization().repaint();
175         
176         down.setLocation(temp);
177         if ( action != null )
178             d.getVisualization().run(action);
179     }
180 
181     /**
182      * @see prefuse.data.event.TableListener#tableChanged(prefuse.data.Table, int, int, int, int)
183      */
184     public void tableChanged(Table t, int start, int end, int col, int type) {
185         if ( activeItem == null || type != EventConstants.UPDATE 
186                 || col != t.getColumnNumber(VisualItem.FIXED) )
187             return;
188         int row = activeItem.getRow();
189         if ( row >= start && row <= end )
190             resetItem = false;
191     }
192 
193 } // end of class DragControl
194
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