Adding overlay object for displaying wind field.

java/com.sap.sailing.gwt.ui/src/main/java/com/sap/sailing/gwt/ui/simulator/WindFieldCanvasOverlay.java

@@ -0,0 +1,147 @@
+package com.sap.sailing.gwt.ui.simulator;
+
+import java.util.Iterator;
+import java.util.List;
+import java.util.logging.Logger;
+
+import com.google.gwt.canvas.dom.client.Context2d;
+import com.google.gwt.canvas.dom.client.Context2d.LineCap;
+import com.google.gwt.maps.client.geom.LatLng;
+import com.google.gwt.maps.client.geom.Point;
+import com.google.gwt.maps.client.overlay.Overlay;
+import com.sap.sailing.domain.common.impl.DegreeBearingImpl;
+import com.sap.sailing.gwt.ui.shared.PositionDTO;
+import com.sap.sailing.gwt.ui.shared.WindDTO;
+import com.sap.sailing.gwt.ui.shared.WindFieldDTO;
+import com.sap.sailing.gwt.ui.shared.WindLatticeDTO;
+import com.sap.sailing.gwt.ui.shared.racemap.CanvasOverlay;
+
+/**
+ *  A google map overlay based on a HTML5 canvas for drawing a wind field.
+ *  The overlay covers the whole map and displays the wind objects inside it. 
+ * @author Nidhi Sawhney
+ *
+ */
+public class WindFieldCanvasOverlay extends CanvasOverlay {
+    
+   
+    /* x coordinate where the widget is placed */
+    private final int xPos = 0;
+    /* y coordinate where the widget is placed */
+    private final int yPos = 0;
+    
+    /* The windfield that is to be displayed in the overlay */
+    private WindFieldDTO wl;
+    
+    private static Logger logger = Logger.getLogger("com.sap.sailing");
+   
+    public WindFieldCanvasOverlay() {
+        super();
+
+      
+    }
+
+    public void setWindField(WindFieldDTO wl) {
+        this.wl = wl;
+    }
+
+
+    @Override
+    protected Overlay copy() {
+        return new WindFieldCanvasOverlay();
+    }
+
+    @Override
+    protected void redraw(boolean force) {
+
+       if (wl != null) {
+           int canvasWidth = getMap().getSize().getWidth();
+           int canvasHeight = getMap().getSize().getWidth();
+           canvas.setWidth(String.valueOf(canvasWidth));
+           canvas.setHeight(String.valueOf(canvasHeight));
+           canvas.setCoordinateSpaceWidth(canvasWidth);
+           canvas.setCoordinateSpaceHeight(canvasHeight);
+
+           drawWindField();
+           
+           getPane().setWidgetPosition(getCanvas(),xPos,yPos);
+       }
+
+    }
+    
+    private void drawWindField() {
+        logger.fine("In WindFieldCanvasOverlay.drawWindField");
+        List<WindDTO> windDTOList = wl.getMatrix();
+        
+        if (windDTOList != null && windDTOList.size() > 0)  {
+            Iterator<WindDTO> windDTOIter = windDTOList.iterator();
+            while (windDTOIter.hasNext()) {
+                WindDTO windDTO = windDTOIter.next();
+                double length = 10;
+                int width = (int) Math.round(windDTO.trueWindSpeedInMetersPerSecond);
+                DegreeBearingImpl dbi = new DegreeBearingImpl(windDTO.trueWindBearingDeg);
+                drawArrow(windDTO.position, dbi.getRadians(), length, width);
+            }
+        }
+    }
+    
+    private void drawArrow(PositionDTO position, double angle, double length, double weight) {
+        
+        Context2d context2d = canvas.getContext2d();
+        context2d.setStrokeStyle("Blue");
+        //context2d.setLineCap(LineCap.SQUARE);
+        context2d.setLineWidth(weight);
+        context2d.beginPath();
+        
+        Point canvasPositionInPx = getMap().convertLatLngToDivPixel(LatLng.newInstance(position.latDeg,position.lngDeg));
+        int x = canvasPositionInPx.getX();
+        int y = canvasPositionInPx.getY();
+       
+       
+        context2d.moveTo(x,y);
+        double dx = length * Math.cos(angle);
+        double dy = length * Math.sin(angle);
+        double x1 = x + dx;
+        double y1 = y + dy;
+        context2d.lineTo(x1,y1);
+        context2d.closePath();
+        context2d.stroke();
+       
+        double theta = Math.atan2(-dy, dx);
+        
+        drawHead(x1, y1, theta, length / 2, weight);
+    }
+    
+    private void drawHead(double x, double y, double theta, double headLength, double weight) {
+        
+        double t = theta + (Math.PI / 4);
+        if (t > Math.PI)
+            t -= 2 * Math.PI;
+        double t2 = theta - (Math.PI / 4);
+        if (t2 <= (-Math.PI))
+            t2 += 2 * Math.PI;
+     
+        double x1 = Math.round(x - Math.cos(t) * headLength);
+        double y1 = Math.round(y + Math.sin(t) * headLength);
+        double x2 = Math.round(x - Math.cos(t2) * headLength);
+        double y2 = Math.round(y + Math.sin(t2) * headLength);
+        Context2d context2d = canvas.getContext2d();
+        context2d.setStrokeStyle("Red");
+        context2d.setLineWidth(weight);
+        context2d.beginPath();
+        context2d.moveTo(x, y);
+        context2d.lineTo(x1,y1);
+        context2d.closePath();
+        context2d.stroke();
+        
+        context2d.beginPath();
+        context2d.moveTo(x, y);
+        context2d.lineTo(x2,y2);
+        context2d.closePath();
+        context2d.stroke();
+       
+    }
+
+ }
+
+