+package tim.prune.gui.map;
+
+import java.awt.Color;
+import java.awt.Dimension;
+import java.awt.Graphics;
+import javax.swing.JPanel;
+
+import tim.prune.I18nManager;
+import tim.prune.config.ColourScheme;
+import tim.prune.config.Config;
+import tim.prune.data.Unit;
+
+/**
+ * Class to show a scale bar on the main map of GpsPrune
+ */
+public class ScaleBar extends JPanel
+{
+ /** zoom level */
+ private int _zoomLevel = -1;
+ /** y position */
+ private double _yPos = 0.0;
+
+ // 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;
+
+ /** scales for each zoom level */
+ private static final int[] _scales = {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 double[] _metricPixels = {64, 64, 51, 102, 102, 102, 81, 81,
+ 81, 65, 65, 65, 52, 105, 105,
+ 105, 83, 83, 83, 67, 67, 67};
+
+
+ /**
+ * 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 {
+ final double distScaleFactor = Config.getUnitSet().getDistanceUnit().getMultFactorFromStd();
+ double drightSide = LEFT_OFFSET + _metricPixels[_zoomLevel] / 1000.0 / distScaleFactor;
+ int scale = _scales[_zoomLevel];
+
+ // work out cos(latitude) from y position, and apply to scale
+ final double angle = Math.PI * (1 - 2*_yPos);
+ final double lat = Math.atan(Math.sinh(angle));
+ final double cosLat = Math.cos(lat);
+ int rightSide = (int) (drightSide / 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;}
+ }
+ // Abort if scale is negative (around poles)
+ if (rightSide < 1) {return;}
+
+ // Determine colours to use
+ Color barColour = Config.getColourScheme().getColour(ColourScheme.IDX_TEXT);
+ Color blankColour = new Color(255-barColour.getRed(), 255-barColour.getGreen(), 255-barColour.getBlue());
+ // Should this blank colour be set to saturation zero?
+ // Draw blank bars behind
+ inG.setColor(blankColour);
+ inG.drawLine(LEFT_OFFSET, Y_OFFSET-1, rightSide+2, Y_OFFSET-1);
+ inG.drawLine(LEFT_OFFSET, Y_OFFSET+2, rightSide+2, Y_OFFSET+2);
+ inG.drawLine(LEFT_OFFSET-1, Y_OFFSET+2, LEFT_OFFSET-1, Y_OFFSET-TICK_HEIGHT);
+ inG.drawLine(LEFT_OFFSET+2, Y_OFFSET+2, LEFT_OFFSET+2, Y_OFFSET-TICK_HEIGHT);
+ inG.drawLine(rightSide-1, Y_OFFSET+2, rightSide-1, Y_OFFSET-TICK_HEIGHT);
+ inG.drawLine(rightSide+2, Y_OFFSET+2, rightSide+2, Y_OFFSET-TICK_HEIGHT);
+ // horizontal
+ inG.setColor(barColour);
+ 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+1, rightSide, Y_OFFSET-TICK_HEIGHT);
+ inG.drawLine(rightSide+1, Y_OFFSET+1, rightSide+1, Y_OFFSET-TICK_HEIGHT);
+ // text
+ String text = getScaleText(scale, Config.getUnitSet().getDistanceUnit());
+ inG.setColor(blankColour);
+ inG.drawString(text, rightSide+MARGIN_WIDTH-1, Y_OFFSET);
+ inG.drawString(text, rightSide+MARGIN_WIDTH+1, Y_OFFSET);
+ inG.drawString(text, rightSide+MARGIN_WIDTH, Y_OFFSET-1);
+ inG.drawString(text, rightSide+MARGIN_WIDTH, Y_OFFSET+1);
+ inG.setColor(barColour);
+ inG.drawString(text, rightSide+MARGIN_WIDTH, Y_OFFSET);
+ }
+ catch (ArrayIndexOutOfBoundsException ai) {}
+ }
+ }
+
+ /**
+ * Get the scale text for the given scale
+ * @param inScale scale number
+ * @param inDistUnit distance unit
+ * @return scale text as string
+ */
+ private static String getScaleText(int inScale, Unit inDistUnit)
+ {
+ if (inScale > 0) {
+ // Positive scale means km or miles
+ return "" + inScale + " " +
+ I18nManager.getText(inDistUnit.getShortnameKey());
+ }
+ // negative scale means a fraction
+ return "" + (-1.0 / inScale) + " " + I18nManager.getText(inDistUnit.getShortnameKey());
+ // might be nice to say 100m instead of 0.1km, 275ft instead of 0.2miles, etc - need to be done by Unit itself?
+ }
+
+ /**
+ * Update the scale level
+ * @param inZoom new zoom level
+ * @param inYPos y position, where 0 is north pole, 1 is south pole
+ */
+ public void updateScale(int inZoom, double inYPos)
+ {
+ _zoomLevel = inZoom;
+ _yPos = inYPos;
+ }
+}