git-svn-id: https://samskivert.googlecode.com/svn/trunk@1080 6335cc39-0255-0410-8fd6-9bcaacd3b74c

2003-03-26 09:27:43 +00:00
parent 17060cfb2e
commit 746170698a
1 changed files with 162 additions and 0 deletions
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+//
+// $Id: ScrollBox.java,v 1.1 2003/03/26 09:27:43 ray Exp $
+
+package com.samskivert.swing;
+
+import java.awt.Color;
+import java.awt.Graphics;
+import java.awt.Point;
+import java.awt.Rectangle;
+
+import java.awt.event.MouseEvent;
+
+import javax.swing.BoundedRangeModel;
+import javax.swing.JPanel;
+import javax.swing.JScrollPane;
+
+import javax.swing.event.ChangeEvent;
+import javax.swing.event.ChangeListener;
+import javax.swing.event.MouseInputAdapter;
+
+/**
+ * A non-annoying way to do two-dimensional scrolling.
+ * Because horizontal scrollbars are the devil's toys.
+ */
+public class ScrollBox extends JPanel
+{
+    /**
+     * Construct the box to work on the specified scrollpane.
+     */
+    public ScrollBox (JScrollPane pane)
+    {
+        this(pane.getHorizontalScrollBar().getModel(),
+             pane.getVerticalScrollBar().getModel());
+    }
+
+    /**
+     * Construct with the specified range models.
+     */
+    public ScrollBox (BoundedRangeModel horz, BoundedRangeModel vert)
+    {
+        _horz = horz;
+        _vert = vert;
+
+        addMouseListener(_mouser);
+        addMouseMotionListener(_mouser);
+    }
+
+    // documentation inherited
+    public void addNotify ()
+    {
+        super.addNotify();
+
+        _horz.addChangeListener(_changebob);
+        _vert.addChangeListener(_changebob);
+        updateBox();
+    }
+
+    // documentation inherited
+    public void removeNotify ()
+    {
+        super.removeNotify();
+
+        _horz.removeChangeListener(_changebob);
+        _vert.removeChangeListener(_changebob);
+    }
+
+    // documentation inherited
+    public void setBounds (int x, int y, int w, int h)
+    {
+        super.setBounds(x, y, w, h);
+        updateBox();
+    }
+
+    // documentation inherited
+    public void paintComponent (Graphics g)
+    {
+        g.setColor(getBackground());
+        g.fillRect(0, 0, getWidth(), getHeight());
+
+        g.setColor(getForeground());
+        g.drawRect(_box.x, _box.y, _box.width, _box.height);
+    }
+
+    /**
+     * Recalculate the size of the box.
+     */
+    protected void updateBox ()
+    {
+        _hFactor = (getWidth() - 1) /
+            (float) (_horz.getMaximum() - _horz.getMinimum());
+        _vFactor = (getHeight() - 1) /
+            (float) (_vert.getMaximum() - _horz.getMinimum());
+
+        _box.x = (int) Math.round(_horz.getValue() * _hFactor);
+        _box.width = (int) Math.round(_horz.getExtent() * _hFactor);
+
+        _box.y = (int) Math.round(_vert.getValue() * _vFactor);
+        _box.height = (int) Math.round(_vert.getExtent() * _vFactor);
+    }
+
+    /** The bounds that we observe / modify. */
+    protected BoundedRangeModel _horz, _vert;
+
+    /** The box that we're spanking. */
+    protected Rectangle _box = new Rectangle();
+
+    /** The conversion factor from one pixel to one unit of bounded range. */
+    protected float _hFactor, _vFactor;
+
+    /**
+     * Listens to mouse events and updates the models.
+     */
+    protected MouseInputAdapter _mouser = new MouseInputAdapter ()
+    {
+        // documentation inherited
+        public void mousePressed (MouseEvent e)
+        {
+            if (e.getButton() == MouseEvent.BUTTON1) {
+                Point p = e.getPoint();
+                if (_box.contains(p)) {
+                    _lastPoint = p;
+                }
+            }
+        }
+
+        // documentation inherited
+        public void mouseDragged (MouseEvent e)
+        {
+            if (_lastPoint != null) {
+                Point p = e.getPoint();
+                _horz.setValue(_horz.getValue() +
+                    (int) Math.round((p.x - _lastPoint.x) / _hFactor));
+                _vert.setValue(_vert.getValue() +
+                    (int) Math.round((p.y - _lastPoint.y) / _vFactor));
+                _lastPoint = p;
+            }
+        }
+
+        // documentation inherited
+        public void mouseReleased (MouseEvent e)
+        {
+            if (e.getButton() == MouseEvent.BUTTON1) {
+                _lastPoint = null;
+            }
+        }
+
+        /** The last point with which we compare drag points. */
+        protected Point _lastPoint;
+    };
+
+    /**
+     * Listens to both range models and updates us when they change.
+     */
+    protected ChangeListener _changebob = new ChangeListener() {
+        // documentation inherited
+        public void stateChanged (ChangeEvent e)
+        {
+            updateBox();
+            repaint();
+        }
+    };
+}