Bug 193467 URL hyperlink can't work in chart viewer
chart/org.eclipse.birt.chart.viewer/src/org/eclipse/birt/chart/viewer/internal/util/ChartImageManager.java
return null;
			}
			if ( ( ex instanceof ChartException && ( (ChartException) ex ).getType( ) == ChartException.INVALID_IMAGE_SIZE ) )
			{
				
				
				return null;
			}
			throw birtException;
		}
		catch ( RuntimeException ex )
		{
			throw new ChartException( ChartEnginePlugin.ID,
					ChartException.GENERATION,
					ex );
		}
		return fis;
	}
	private void generateImage( ) throws Exception
	{
		String imageName = IMAGE_NAME_PREFIX
				+ +imageIndex++ + "." + this.sExtension.toLowerCase( ); 
		imageFile = new File( getAbsoluteImageFolder( )
				+ File.separator + imageName );
		if ( !imageFile.getParentFile( ).exists( ) )
		{
			imageFile.getParentFile( ).mkdirs( );
		}
		System.out.println( "Generated file: " + imageFile.getPath( ) );