code: @Override
      protected boolean prepare(final Context2D context, final Attributes attr, final double alpha)
      {
          final double w = attr.getWidth();
  
          final double h = attr.getHeight();
  
          final double r = attr.getCornerRadius();
  
          if ((w > 0) && (h > 0))
          {
              context.beginPath();
  
              if ((r > 0) && (r < (w / 2)) && (r < (h / 2)))
              {
                  context.moveTo(r, 0);
  
                  context.lineTo(w - r, 0);
  
                  context.arc(w - r, r, r, (Math.PI * 3) / 2, 0, false);
  
                  context.lineTo(w, h - r);
  
                  context.arc(w - r, h - r, r, 0, Math.PI / 2, false);
  
                  context.lineTo(r, h);
  
                  context.arc(r, h - r, r, Math.PI / 2, Math.PI, false);
  
                  context.lineTo(0, r);
  
                  context.arc(r, r, r, Math.PI, (Math.PI * 3) / 2, false);
              }
              else
              {
                  context.rect(0, 0, w, h);
              }
              context.closePath();
  
              return true;
          }
          return false;
      }
docs: Draws this rectangle.
  
  @param context