Bug 312531 Highlight works differently when run SvgInteractivityViewer.java [13]
chart/org.eclipse.birt.chart.device.svg/src/org/eclipse/birt/chart/device/svg/SVGGraphics2D.java
if (img==null)
		{
			return null;
		}
		
		int width = img.getWidth( );
		int height = img.getHeight( );
		ImageWriter iw = ImageWriterFactory.instance( )
				.createByFormatName( "gif" ); 
		ByteArrayOutputStream baos = new ByteArrayOutputStream( 8192*2 );
		String sUrl = null;
		try
		{
			final ImageOutputStream ios = SecurityUtil.newImageOutputStream( baos );
			ImageWriteParam iwp = iw.getDefaultWriteParam( );
			iw.setOutput( ios );
			iw.write( (IIOMetadata) null, new IIOImage( img, null, null ), iwp );
			img.flush( );
			ios.close( );
			sUrl = SVGImage.BASE64
					+ new String( Base64.encodeBase64( baos.toByteArray( ) ) );
		}
		catch ( Exception ex )
		{
			logger.log( ex );
		}
		finally
		{
			iw.dispose( );
		}