Version 8, September 2009

[GpsPrune.git] / tim / prune / gui / map / ScaleBar.java

diff --git a/tim/prune/gui/map/ScaleBar.java b/tim/prune/gui/map/ScaleBar.java
new file mode 100644 (file)
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--- /dev/null
+++ b/tim/prune/gui/map/ScaleBar.java
@@ -0,0 +1,111 @@
+package tim.prune.gui.map;
+
+import java.awt.Color;
+import java.awt.Dimension;
+import java.awt.Graphics;
+import javax.swing.JPanel;
+
+import tim.prune.Config;
+import tim.prune.I18nManager;
+
+/**
+ * Class to show a scale bar on the main map of Prune
+ */
+public class ScaleBar extends JPanel
+{
+       /** zoom level */
+       private int _zoomLevel = -1;
+       /** y tile number */
+       private int _yTile = -1;
+
+       // Dimensions
+       /** Offset from left side in pixels */
+       private static final int LEFT_OFFSET = 20;
+       /** Offset from top in pixels */
+       private static final int Y_OFFSET = 10;
+       /** Tick height in pixels */
+       private static final int TICK_HEIGHT = 5;
+       /** Margin between bar and end text in pixels */
+       private static final int MARGIN_WIDTH = 8;
+
+       /** metric scales for each zoom level */
+       private static final int[] _metricScales = {10000, 5000, 2000, 2000, 1000, 500, 200, 100,
+               50, 20, 10, 5, 2, 2, 1, -2, -5, -10, -20, -50, -100, -200};
+       /** pixel counts for each zoom level (metric) */
+       private static final int[] _metricPixels = {64, 64, 51, 102, 102, 102, 81, 81,
+               81, 65, 65, 65, 52, 105, 105, 105, 83, 83, 83, 67, 67, 67};
+       /** imperial scales for each zoom level (num miles) */
+       private static final int[] _mileScales = {10000, 10000, 5000, 2000, 2000, 1000, 500, 200,
+               100, 50, 20, 10, 5, 2, 1, -2, -2, -5, -10, -20, -50, -100};
+       /** pixel counts for each zoom level (miles) */
+       private static final int[] _milePixels = {79, 79, 79, 64, 127, 127, 127, 102,
+               102, 102, 81, 81, 81, 65, 65, 65, 130, 104, 104, 104, 104, 83, 83};
+
+
+       /**
+        * Constructor
+        */
+       public ScaleBar()
+       {
+               super();
+               setOpaque(false);
+               setPreferredSize(new Dimension(100, 20));
+       }
+
+       /**
+        * Paint method to override display
+        * @param inG graphics object
+        */
+       public void paint(Graphics inG)
+       {
+               super.paint(inG);
+               if (_zoomLevel > -1)
+               {
+                       try {
+                               boolean useMetric = Config.getConfigBoolean(Config.KEY_METRIC_UNITS);
+                               int rightSide = LEFT_OFFSET + (useMetric?_metricPixels[_zoomLevel]:_milePixels[_zoomLevel]);
+                               int scale = (useMetric?_metricScales[_zoomLevel]:_mileScales[_zoomLevel]);
+
+                               // work out cos(latitude) from y tile and zoom, and apply to scale
+                               final double n = Math.pow(2, _zoomLevel);
+                               final double angle = Math.PI * (1 - 2.0*_yTile/n);
+                               final double lat = Math.atan(Math.sinh(angle));
+                               final double cosLat = Math.cos(lat);
+                               rightSide = (int) (rightSide / cosLat);
+                               // Adjust if scale is too large
+                               while (rightSide > 300)
+                               {
+                                       rightSide /= 2;
+                                       scale /= 2;
+                                       // Abort if scale is now less than 1 unit (shouldn't ever be)
+                                       if (scale < 1) {return;}
+                               }
+
+                               // horizontal
+                               inG.setColor(Color.BLACK);
+                               inG.drawLine(LEFT_OFFSET, Y_OFFSET, rightSide, Y_OFFSET);
+                               inG.drawLine(LEFT_OFFSET, Y_OFFSET+1, rightSide, Y_OFFSET+1);
+                               // 0 tick
+                               inG.drawLine(LEFT_OFFSET, Y_OFFSET, LEFT_OFFSET, Y_OFFSET-TICK_HEIGHT);
+                               inG.drawLine(LEFT_OFFSET+1, Y_OFFSET, LEFT_OFFSET+1, Y_OFFSET-TICK_HEIGHT);
+                               // end tick
+                               inG.drawLine(rightSide, Y_OFFSET, rightSide, Y_OFFSET-TICK_HEIGHT);
+                               inG.drawLine(rightSide+1, Y_OFFSET, rightSide+1, Y_OFFSET-TICK_HEIGHT);
+                               // text
+                               String text = (scale>0?(""+scale):("1/"+(-scale))) + " " + I18nManager.getText(useMetric?"units.kilometres.short":"units.miles.short");
+                               inG.drawString(text, rightSide+MARGIN_WIDTH, Y_OFFSET);
+                       }
+                       catch (ArrayIndexOutOfBoundsException ai) {}
+               }
+       }
+
+       /**
+        * Update the scale level
+        * @param inZoom new zoom level
+        */
+       public void updateScale(int inZoom, int inYtile)
+       {
+               _zoomLevel = inZoom;
+               _yTile = inYtile;
+       }
+}