code: protected Object getImageSource(String control)
      {
          if (control.equals(AVKey.VIEW_PAN))
              return IMAGE_PAN;
          else if (control.equals(AVKey.VIEW_LOOK))
              return IMAGE_LOOK;
          else if (control.equals(AVKey.VIEW_HEADING_LEFT))
              return IMAGE_HEADING_LEFT;
          else if (control.equals(AVKey.VIEW_HEADING_RIGHT))
              return IMAGE_HEADING_RIGHT;
          else if (control.equals(AVKey.VIEW_ZOOM_IN))
              return IMAGE_ZOOM_IN;
          else if (control.equals(AVKey.VIEW_ZOOM_OUT))
              return IMAGE_ZOOM_OUT;
          else if (control.equals(AVKey.VIEW_PITCH_UP))
              return IMAGE_PITCH_UP;
          else if (control.equals(AVKey.VIEW_PITCH_DOWN))
              return IMAGE_PITCH_DOWN;
          else if (control.equals(AVKey.VIEW_FOV_WIDE))
              return IMAGE_FOV_WIDE;
          else if (control.equals(AVKey.VIEW_FOV_NARROW))
              return IMAGE_FOV_NARROW;
          else if (control.equals(AVKey.VERTICAL_EXAGGERATION_UP))
              return IMAGE_VE_UP;
          else if (control.equals(AVKey.VERTICAL_EXAGGERATION_DOWN))
              return IMAGE_VE_DOWN;
  
          return null;
      }
docs: Get a control image source.
  
  @param control the control type. Can be one of {@link AVKey#VIEW_PAN}, {@link AVKey#VIEW_LOOK}, {@link
  AVKey#VIEW_HEADING_LEFT}, {@link AVKey#VIEW_HEADING_RIGHT}, {@link AVKey#VIEW_ZOOM_IN}, {@link
  AVKey#VIEW_ZOOM_OUT}, {@link AVKey#VIEW_PITCH_UP}, {@link AVKey#VIEW_PITCH_DOWN}, {@link
  AVKey#VIEW_FOV_NARROW} or {@link AVKey#VIEW_FOV_WIDE}.
  
  @return the image source associated with the given control type.