tim/prune/gui/map/ScaleBar.java

   1 package tim.prune.gui.map;
   2
   3 import java.awt.Color;
   4 import java.awt.Dimension;
   5 import java.awt.Graphics;
   6 import javax.swing.JPanel;
   7
   8 import tim.prune.I18nManager;
   9 import tim.prune.config.ColourScheme;
  10 import tim.prune.config.Config;
  11 import tim.prune.data.Unit;
  12
  13 /**
  14  * Class to show a scale bar on the main map of GpsPrune
  15  */
  16 public class ScaleBar extends JPanel
  17 {
  18         /** zoom level */
  19         private int _zoomLevel = -1;
  20         /** y position */
  21         private double _yPos = 0.0;
  22
  23         // Dimensions
  24         /** Offset from left side in pixels */
  25         private static final int LEFT_OFFSET = 20;
  26         /** Offset from top in pixels */
  27         private static final int Y_OFFSET = 10;
  28         /** Tick height in pixels */
  29         private static final int TICK_HEIGHT = 5;
  30         /** Margin between bar and end text in pixels */
  31         private static final int MARGIN_WIDTH = 8;
  32
  33         /** scales for each zoom level */
  34         private static final int[] _scales = {10000, 5000, 2000, 2000, 1000, 500, 200, 100,
  35                 50, 20, 10, 5, 2, 2, 1,
  36                 -2, -5, -10, -20, -50, -100, -200};
  37         /** pixel counts for each zoom level (metric) */
  38         private static final double[] _metricPixels = {64, 64, 51, 102, 102, 102, 81, 81,
  39                 81, 65, 65, 65, 52, 105, 105,
  40                 105, 83, 83, 83, 67, 67, 67};
  41
  42
  43         /**
  44          * Constructor
  45          */
  46         public ScaleBar()
  47         {
  48                 super();
  49                 setOpaque(false);
  50                 setPreferredSize(new Dimension(100, 20));
  51         }
  52
  53         /**
  54          * Paint method to override display
  55          * @param inG graphics object
  56          */
  57         public void paint(Graphics inG)
  58         {
  59                 super.paint(inG);
  60                 if (_zoomLevel > -1)
  61                 {
  62                         try {
  63                                 final double distScaleFactor = Config.getUnitSet().getDistanceUnit().getMultFactorFromStd();
  64                                 double drightSide = LEFT_OFFSET + _metricPixels[_zoomLevel] / 1000.0 / distScaleFactor;
  65                                 int scale = _scales[_zoomLevel];
  66
  67                                 // work out cos(latitude) from y position, and apply to scale
  68                                 final double angle = Math.PI * (1 - 2*_yPos);
  69                                 final double lat = Math.atan(Math.sinh(angle));
  70                                 final double cosLat = Math.cos(lat);
  71                                 int rightSide = (int) (drightSide / cosLat);
  72                                 // Adjust if scale is too large
  73                                 while (rightSide > 300)
  74                                 {
  75                                         rightSide /= 2;
  76                                         scale /= 2;
  77                                         // Abort if scale is now less than 1 unit (shouldn't ever be)
  78                                         if (scale < 1) {return;}
  79                                 }
  80                                 // Abort if scale is negative (around poles)
  81                                 if (rightSide < 1) {return;}
  82
  83                                 // Determine colours to use
  84                                 Color barColour = Config.getColourScheme().getColour(ColourScheme.IDX_TEXT);
  85                                 Color blankColour = new Color(255-barColour.getRed(), 255-barColour.getGreen(), 255-barColour.getBlue());
  86                                 // Should this blank colour be set to saturation zero?
  87                                 // Draw blank bars behind
  88                                 inG.setColor(blankColour);
  89                                 inG.drawLine(LEFT_OFFSET, Y_OFFSET-1, rightSide+2, Y_OFFSET-1);
  90                                 inG.drawLine(LEFT_OFFSET, Y_OFFSET+2, rightSide+2, Y_OFFSET+2);
  91                                 inG.drawLine(LEFT_OFFSET-1, Y_OFFSET+2, LEFT_OFFSET-1, Y_OFFSET-TICK_HEIGHT);
  92                                 inG.drawLine(LEFT_OFFSET+2, Y_OFFSET+2, LEFT_OFFSET+2, Y_OFFSET-TICK_HEIGHT);
  93                                 inG.drawLine(rightSide-1, Y_OFFSET+2, rightSide-1, Y_OFFSET-TICK_HEIGHT);
  94                                 inG.drawLine(rightSide+2, Y_OFFSET+2, rightSide+2, Y_OFFSET-TICK_HEIGHT);
  95                                 // horizontal
  96                                 inG.setColor(barColour);
  97                                 inG.drawLine(LEFT_OFFSET, Y_OFFSET, rightSide, Y_OFFSET);
  98                                 inG.drawLine(LEFT_OFFSET, Y_OFFSET+1, rightSide, Y_OFFSET+1);
  99                                 // 0 tick
 100                                 inG.drawLine(LEFT_OFFSET, Y_OFFSET, LEFT_OFFSET, Y_OFFSET-TICK_HEIGHT);
 101                                 inG.drawLine(LEFT_OFFSET+1, Y_OFFSET, LEFT_OFFSET+1, Y_OFFSET-TICK_HEIGHT);
 102                                 // end tick
 103                                 inG.drawLine(rightSide, Y_OFFSET+1, rightSide, Y_OFFSET-TICK_HEIGHT);
 104                                 inG.drawLine(rightSide+1, Y_OFFSET+1, rightSide+1, Y_OFFSET-TICK_HEIGHT);
 105                                 // text
 106                                 String text = getScaleText(scale, Config.getUnitSet().getDistanceUnit());
 107                                 inG.setColor(blankColour);
 108                                 inG.drawString(text, rightSide+MARGIN_WIDTH-1, Y_OFFSET);
 109                                 inG.drawString(text, rightSide+MARGIN_WIDTH+1, Y_OFFSET);
 110                                 inG.drawString(text, rightSide+MARGIN_WIDTH, Y_OFFSET-1);
 111                                 inG.drawString(text, rightSide+MARGIN_WIDTH, Y_OFFSET+1);
 112                                 inG.setColor(barColour);
 113                                 inG.drawString(text, rightSide+MARGIN_WIDTH, Y_OFFSET);
 114                         }
 115                         catch (ArrayIndexOutOfBoundsException ai) {}
 116                 }
 117         }
 118
 119         /**
 120          * Get the scale text for the given scale
 121          * @param inScale scale number
 122          * @param inDistUnit distance unit
 123          * @return scale text as string
 124          */
 125         private static String getScaleText(int inScale, Unit inDistUnit)
 126         {
 127                 if (inScale > 0) {
 128                         // Positive scale means km or miles
 129                         return "" + inScale     + " " +
 130                                 I18nManager.getText(inDistUnit.getShortnameKey());
 131                 }
 132                 // negative scale means a fraction
 133                 return "" + (-1.0 / inScale) + " " + I18nManager.getText(inDistUnit.getShortnameKey());
 134                 // might be nice to say 100m instead of 0.1km, 275ft instead of 0.2miles, etc - need to be done by Unit itself?
 135         }
 136
 137         /**
 138          * Update the scale level
 139          * @param inZoom new zoom level
 140          * @param inYPos y position, where 0 is north pole, 1 is south pole
 141          */
 142         public void updateScale(int inZoom, double inYPos)
 143         {
 144                 _zoomLevel = inZoom;
 145                 _yPos = inYPos;
 146         }
 147 }