Added class to extend CanvasOverlay to be the full viewable map.

java/com.sap.sailing.gwt.ui/src/main/java/com/sap/sailing/gwt/ui/shared/racemap/FullCanvasOverlay.java

@@ -0,0 +1,134 @@
+package com.sap.sailing.gwt.ui.shared.racemap;
+
+import com.google.gwt.canvas.dom.client.Context2d;
+import com.google.gwt.maps.client.geom.Point;
+
+/**
+ * This class extends @CanvasOverlay to provide the functionality that the canvas always covers the
+ * full viewable area of the map
+ * 
+ * @author Nidhi Sawhney(D054070)
+ *
+ */
+public abstract class FullCanvasOverlay extends CanvasOverlay {
+
+    /* x coordinate where the widget is placed */
+    protected int widgetPosLeft = 0;
+    /* y coordinate where the widget is placed */
+    protected int widgetPosTop = 0;
+
+    /* Set the canvas to be the size of the map and set it to the top left corner of the map */
+    protected void setCanvasSettings() {
+        int canvasWidth = getMap().getSize().getWidth();
+        int canvasHeight = getMap().getSize().getHeight();
+   
+        canvas.setWidth(String.valueOf(canvasWidth));
+        canvas.setHeight(String.valueOf(canvasHeight));
+        canvas.setCoordinateSpaceWidth(canvasWidth);
+        canvas.setCoordinateSpaceHeight(canvasHeight);
+   
+        Point sw = getMap().convertLatLngToDivPixel(getMap().getBounds().getSouthWest());
+        Point ne = getMap().convertLatLngToDivPixel(getMap().getBounds().getNorthEast());
+        widgetPosLeft = Math.min(sw.getX(), ne.getX());
+        widgetPosTop = Math.min(sw.getY(), ne.getY());
+          
+        getPane().setWidgetPosition(getCanvas(), widgetPosLeft, widgetPosTop);
+        
+    }
+    
+    @Override
+    protected void redraw(boolean force) {
+        /*
+         * Reset the canvas only if the pixel coordinates need to be recomputed
+         */
+        if (force) {
+            setCanvasSettings();
+        }
+    }
+    
+    /**
+     * Draw a point on the canvas
+     * @param x coordinate wrt the canvas
+     * @param y coordinate wrt the canvas
+     */
+    protected void drawPoint(double x, double y) {
+        Context2d context2d = canvas.getContext2d();
+        context2d.setStrokeStyle("Red");
+        context2d.setLineWidth(3);
+        context2d.beginPath();
+        context2d.moveTo(x, y);
+        context2d.lineTo(x, y);
+        context2d.closePath();
+        context2d.stroke();
+        
+        
+    }
+    
+    /**
+     * Draw a point and a text on the canvas
+     * @param x coordinate wrt the canvas
+     * @param y coordinate wrt the canvas
+     * @param text to be displayed at the point on the canvas
+     */
+    protected void drawPointWithText(double x, double y, String text) {
+        
+        Context2d context2d = canvas.getContext2d();
+        drawPoint(x, y);
+        context2d.setFillStyle("Black");
+        context2d.fillText(text, x, y);
+       
+    }
+    
+    /**
+     * Draw a line from (x,y) to (x1,y1) on the canvas
+     * @param x
+     * @param y
+     * @param x1
+     * @param y1
+     */
+    protected void drawLine(double x, double y, double x1, double y1, double weight, String color) {
+        Context2d context2d  = canvas.getContext2d();
+        context2d.setLineWidth(weight);
+        context2d.setStrokeStyle(color);
+        context2d.beginPath();
+        context2d.moveTo(x, y);
+        context2d.lineTo(x1, y1);
+        context2d.closePath();
+        context2d.stroke();
+    }
+    
+    /**
+     * Debug function to draw the boundaries of the canvas
+     */
+    protected void drawCanvas() {
+       
+        Context2d context2d  = canvas.getContext2d();
+        context2d.setStrokeStyle("Black");
+        context2d.setLineWidth(3);
+       
+        context2d.beginPath();
+        context2d.moveTo(0,0);
+        context2d.lineTo(0, canvas.getCoordinateSpaceHeight());
+        context2d.closePath();
+        context2d.stroke();
+        
+        context2d.beginPath();
+        context2d.moveTo(0,0);
+        context2d.lineTo(canvas.getCoordinateSpaceWidth(),0);
+        context2d.closePath();
+        context2d.stroke();
+        
+        context2d.beginPath();   
+        context2d.moveTo(canvas.getCoordinateSpaceWidth(),0);
+        context2d.lineTo(canvas.getCoordinateSpaceWidth(), canvas.getCoordinateSpaceHeight());
+        context2d.closePath();
+        context2d.stroke();
+        
+        context2d.beginPath();   
+        context2d.moveTo(0, canvas.getCoordinateSpaceHeight());
+        context2d.lineTo(canvas.getCoordinateSpaceWidth(), canvas.getCoordinateSpaceHeight());
+        context2d.closePath();
+        context2d.stroke();
+        
+    }
+}