code: public CmsJspImageBean createHiDpiVariation(String hiDpiStr) {
  
          CmsJspImageBean result = null;
          if (hiDpiStr.matches("^[0-9]+(.[0-9]+)?x$")) {
  
              double multiplier = Double.valueOf(hiDpiStr.substring(0, hiDpiStr.length() - 1)).doubleValue();
  
              int targetWidth = (int)Math.round(getScaler().getWidth() * multiplier);
              int targetHeight = (int)Math.round(getScaler().getHeight() * multiplier);
  
              CmsImageScaler targetScaler = createVariation(
                  getWidth(),
                  getHeight(),
                  getBaseScaler(),
                  targetWidth,
                  targetHeight,
                  getQuality());
  
              if (targetScaler != null) {
                  result = createVariation(targetScaler);
              }
  
          } else {
              if (LOG.isWarnEnabled()) {
                  LOG.warn(String.format("Illegal multiplier format: '%s' not usable for image scaling", hiDpiStr));
              }
          }
          return result;
      }
docs: Creates a hi-DPI scaled version of the current image.<p>
  
  @param hiDpiStr the hi-DPI variation to generate, for example "2.5x".<p>
  
  @return a hi-DPI scaled version of the current image