code: public void setResolution(Resolution output, Resolution source)
      {
          Check.notNull(output);
          Check.notNull(source);
  
          xRatio = output.getWidth() / (double) source.getWidth();
          yRatio = output.getHeight() / (double) source.getHeight();
      }
docs: Set the resolution used. This will compute mouse horizontal and vertical ratio.
  
  @param output The resolution output (must not be <code>null</code>).
  @param source The resolution source (must not be <code>null</code>).
  @throws LionEngineException If invalid argument.