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
  12 /**
  13  * Class to show a scale bar on the main map of GpsPrune
  14  */
  15 public class ScaleBar extends JPanel
  16 {
  17         /** zoom level */
  18         private int _zoomLevel = -1;
  19         /** y position */
  20         private double _yPos = 0.0;
  21
  22         // Dimensions
  23         /** Offset from left side in pixels */
  24         private static final int LEFT_OFFSET = 20;
  25         /** Offset from top in pixels */
  26         private static final int Y_OFFSET = 10;
  27         /** Tick height in pixels */
  28         private static final int TICK_HEIGHT = 5;
  29         /** Margin between bar and end text in pixels */
  30         private static final int MARGIN_WIDTH = 8;
  31
  32         /** scales for each zoom level */
  33         private static final int[] _scales = {10000, 5000, 2000, 2000, 1000, 500, 200, 100,
  34                 50, 20, 10, 5, 2, 2, 1,
  35                 -2, -5, -10, -20, -50, -100, -200};
  36         /** pixel counts for each zoom level (metric) */
  37         private static final double[] _metricPixels = {64, 64, 51, 102, 102, 102, 81, 81,
  38                 81, 65, 65, 65, 52, 105, 105,
  39                 105, 83, 83, 83, 67, 67, 67};
  40
  41
  42         /**
  43          * Constructor
  44          */
  45         public ScaleBar()
  46         {
  47                 super();
  48                 setOpaque(false);
  49                 setPreferredSize(new Dimension(100, 20));
  50         }
  51
  52         /**
  53          * Paint method to override display
  54          * @param inG graphics object
  55          */
  56         public void paint(Graphics inG)
  57         {
  58                 super.paint(inG);
  59                 if (_zoomLevel > -1)
  60                 {
  61                         try {
  62                                 boolean useMetric = Config.getConfigBoolean(Config.KEY_METRIC_UNITS);
  63                                 double drightSide = LEFT_OFFSET + _metricPixels[_zoomLevel] * (useMetric?1:1.609);
  64                                 int scale = _scales[_zoomLevel];
  65
  66                                 // work out cos(latitude) from y position, and apply to scale
  67                                 final double angle = Math.PI * (1 - 2*_yPos);
  68                                 final double lat = Math.atan(Math.sinh(angle));
  69                                 final double cosLat = Math.cos(lat);
  70                                 int rightSide = (int) (drightSide / cosLat);
  71                                 // Adjust if scale is too large
  72                                 while (rightSide > 300)
  73                                 {
  74                                         rightSide /= 2;
  75                                         scale /= 2;
  76                                         // Abort if scale is now less than 1 unit (shouldn't ever be)
  77                                         if (scale < 1) {return;}
  78                                 }
  79                                 // Abort if scale is negative (around poles)
  80                                 if (rightSide < 1) {return;}
  81
  82                                 // Determine colours to use
  83                                 Color barColour = Config.getColourScheme().getColour(ColourScheme.IDX_TEXT);
  84                                 Color blankColour = new Color(255-barColour.getRed(), 255-barColour.getGreen(), 255-barColour.getBlue());
  85                                 // Should this blank colour be set to saturation zero?
  86                                 // Draw blank bars behind
  87                                 inG.setColor(blankColour);
  88                                 inG.drawLine(LEFT_OFFSET, Y_OFFSET-1, rightSide+2, Y_OFFSET-1);
  89                                 inG.drawLine(LEFT_OFFSET, Y_OFFSET+2, rightSide+2, Y_OFFSET+2);
  90                                 inG.drawLine(LEFT_OFFSET-1, Y_OFFSET+2, LEFT_OFFSET-1, Y_OFFSET-TICK_HEIGHT);
  91                                 inG.drawLine(LEFT_OFFSET+2, Y_OFFSET+2, LEFT_OFFSET+2, Y_OFFSET-TICK_HEIGHT);
  92                                 inG.drawLine(rightSide-1, Y_OFFSET+2, rightSide-1, Y_OFFSET-TICK_HEIGHT);
  93                                 inG.drawLine(rightSide+2, Y_OFFSET+2, rightSide+2, Y_OFFSET-TICK_HEIGHT);
  94                                 // horizontal
  95                                 inG.setColor(barColour);
  96                                 inG.drawLine(LEFT_OFFSET, Y_OFFSET, rightSide, Y_OFFSET);
  97                                 inG.drawLine(LEFT_OFFSET, Y_OFFSET+1, rightSide, Y_OFFSET+1);
  98                                 // 0 tick
  99                                 inG.drawLine(LEFT_OFFSET, Y_OFFSET, LEFT_OFFSET, Y_OFFSET-TICK_HEIGHT);
 100                                 inG.drawLine(LEFT_OFFSET+1, Y_OFFSET, LEFT_OFFSET+1, Y_OFFSET-TICK_HEIGHT);
 101                                 // end tick
 102                                 inG.drawLine(rightSide, Y_OFFSET+1, rightSide, Y_OFFSET-TICK_HEIGHT);
 103                                 inG.drawLine(rightSide+1, Y_OFFSET+1, rightSide+1, Y_OFFSET-TICK_HEIGHT);
 104                                 // text
 105                                 String text = getScaleText(scale, useMetric);
 106                                 inG.setColor(blankColour);
 107                                 inG.drawString(text, rightSide+MARGIN_WIDTH-1, Y_OFFSET);
 108                                 inG.drawString(text, rightSide+MARGIN_WIDTH+1, Y_OFFSET);
 109                                 inG.drawString(text, rightSide+MARGIN_WIDTH, Y_OFFSET-1);
 110                                 inG.drawString(text, rightSide+MARGIN_WIDTH, Y_OFFSET+1);
 111                                 inG.setColor(barColour);
 112                                 inG.drawString(text, rightSide+MARGIN_WIDTH, Y_OFFSET);
 113                         }
 114                         catch (ArrayIndexOutOfBoundsException ai) {}
 115                 }
 116         }
 117
 118         /**
 119          * Get the scale text for the given scale
 120          * @param inScale scale number
 121          * @param inUseMetric true to use km/m, false for miles/ft
 122          * @return scale text as string
 123          */
 124         private static String getScaleText(int inScale, boolean inUseMetric)
 125         {
 126                 if (inScale > 0) {
 127                         // Positive scale means km or miles
 128                         return "" + inScale     + " " +
 129                                 I18nManager.getText(inUseMetric?"units.kilometres.short":"units.miles.short");
 130                 }
 131                 if (inUseMetric) {
 132                         // negative scale means m
 133                         return "" + (-1000 / inScale) + " " + I18nManager.getText("units.metres.short");
 134                 }
 135                 // fallen through to feet
 136                 return "" + (-5280 / inScale) + " " + I18nManager.getText("units.feet.short");
 137         }
 138
 139         /**
 140          * Update the scale level
 141          * @param inZoom new zoom level
 142          * @param inYPos y position, where 0 is north pole, 1 is south pole
 143          */
 144         public void updateScale(int inZoom, double inYPos)
 145         {
 146                 _zoomLevel = inZoom;
 147                 _yPos = inYPos;
 148         }
 149 }