tim/prune/gui/map/OverlayPanel.java

   1 package tim.prune.gui.map;
   2
   3 import java.awt.Color;
   4 import java.awt.Component;
   5 import java.awt.Graphics;
   6
   7 import javax.swing.JPanel;
   8
   9 /**
  10  * Semi-transparent panel to go on top of the map
  11  * to contain a set of controls
  12  */
  13 public class OverlayPanel extends JPanel
  14 {
  15         // Previous dimensions to see if calculations necessary
  16         private int _prevWidth = -1, _prevHeight = -1;
  17         // Previously calculated border limits
  18         private int _minX, _minY, _width, _height;
  19
  20         /**
  21          * Constructor
  22          */
  23         public OverlayPanel()
  24         {
  25                 setOpaque(false);
  26         }
  27
  28         /**
  29          * Paint the contents
  30          */
  31         public void paint(Graphics g)
  32         {
  33                 int panelWidth = getWidth();
  34                 int panelHeight = getHeight();
  35                 if (panelWidth != _prevWidth || panelHeight != _prevHeight)
  36                 {
  37                         calculateBorder();
  38                         _prevWidth = panelWidth;
  39                         _prevHeight = panelHeight;
  40                 }
  41                 // Draw white background
  42                 final Color BG = new Color(255, 255, 255, 200);
  43                 g.setColor(BG);
  44                 g.fillRect(_minX, _minY, _width, _height);
  45                 // Draw black border
  46                 g.setColor(Color.BLACK);
  47                 g.drawRect(_minX, _minY, _width, _height);
  48                 // Paint everything else
  49                 super.paint(g);
  50         }
  51
  52         /**
  53          * Calculate the boundaries to paint over
  54          */
  55         private void calculateBorder()
  56         {
  57                 final int PADDING = 2;
  58                 // Calculate where the border should be drawn
  59                 final Component firstComp = getComponent(0);
  60                 final Component lastComp = getComponent(getComponentCount()-1);
  61                 _minX = Math.max(firstComp.getX() - PADDING, 0);
  62                 final int maxX = Math.min(lastComp.getX() + lastComp.getWidth() + PADDING, getWidth()-1);
  63                 _width = maxX - _minX;
  64                 _minY = Math.max(Math.min(firstComp.getY(), lastComp.getY()) - PADDING, 0);
  65                 final int maxY = Math.max(firstComp.getY()+firstComp.getHeight(), lastComp.getY()+lastComp.getHeight()) + PADDING;
  66                 _height = maxY - _minY;
  67                 //System.out.println("x from " + minx + " to " + maxx + ", y from " + miny + " to " + maxy);
  68         }
  69 }