/**
	 * Renders the table headers
	 */
	class HeaderRenderer extends GridHeaderRenderer {
		
		HeaderRenderer(){
			//
		}

		@Override
		public boolean notify(int event, Point point, Object value) {
			// TODO Auto-generated method stub
			return false;
		}

		@Override
		public void paint(GC gc, Object value) {
			
			Color backgroundColor = getDisplay().getSystemColor(SWT.COLOR_WIDGET_BACKGROUND);
			Color foregroundColor = new Color(getDisplay(), 255,255,255);
			Color selectionColor = new Color(getDisplay(), 153,204,255);
							
			
			//get column
			GridColumn column = (GridColumn)value;
			
							
			//get selection state
			boolean selected = this.isSelected();
				
			//get coordinates
			int x = getBounds().x; 
			int y = getBounds().y;
			int width = getBounds().width;
            int height = getBounds().height;
			
            //set background color and draw rectangle
			Color oldBackground = gc.getBackground();
			Color oldForeground = gc.getForeground();
							
			if (selected) {
				gc.setBackground(selectionColor);		
				gc.setForeground(foregroundColor);					
				gc.fillGradientRectangle(x, y, width, height, true);
				
				gc.setForeground(selectionColor);
				gc.drawRectangle(x,y,width-1,height-1);
				
			} else {
				gc.setBackground(backgroundColor);		
				gc.setForeground(foregroundColor);					
				gc.fillGradientRectangle(x, y, width, height, true);
				
				//gc.setForeground(oldForeground);
				//gc.drawRectangle(x,y,width,height);
			}
			
			
			gc.setBackground(oldBackground);		
			gc.setForeground(oldForeground);
			
			//draw text
			String text = column.getText();		  
			int textOffset = 3;
	        gc.drawString(text, x+textOffset, y+textOffset, true);  
			
		}

		@Override
		public Point computeSize(GC gc, int wHint, int hHint, Object value) {
			
			//define text offset
			int textOffset = 3;
			
			//get text size
			GridColumn column = (GridColumn)value;
			String text = column.getText();					
			Point p = gc.stringExtent(text);				
			int width = p.x + 3*textOffset;
			int height = p.y;				
			return new Point(width, height);
		}
		
	}