Bug 123939 [Smoke][Regression]Drill through link doesn't work in pdf.
Description: Drill through link doesn't work in pdf. Steps to reproduce: 1. View attached design file url.rptdesign in html/pdf, click the drill though link in the last three image. Result: Drill through link doesn't work in pdf. Some links in html also don't work.
engine/org.eclipse.birt.report.engine.emitter.pdf/src/org/eclipse/birt/report/engine/emitter/pdf/PDFEmitter.java
* @param y				the start Y coordinate at the pdf where the image is positioned
	 * @param width			the width of the background dimension
	 * @param height		the height of the background dimension
	 * @param positionX		the offset X percentage relating to start X
	 * @param positionY		the offset Y percentage relating to start Y
	 * @param repeat		the background-repeat property
	 */
	private void drawBackgroundImage(String imageURI, float x, float y, 
			float width, float height, float positionX, float positionY, String repeat)
	{
		
		if ( null == imageURI )
		{
			return;
		}
		
		String id = imageURI;
		if (reportDesign != null)
		{
			URL url = reportDesign.findResource(imageURI, IResourceLocator.IMAGE);
			if (url != null)
			{
				id = url.toExternalForm();
			}
		}
		
		if(id==null || "".equals(id)) 
		{
			return;
		}