anchor.diff:        : this.width = (width >= 0) ? width : -width * 0,  // Inline _clampToZero.
           this.height = (height >= 0) ? height : -height * 0;
   
  -  /*
  +  /**
      * Create a rectangle spanned by the points [a] and [b];
      *
      * The rectangle contains the points
      * with x-coordinate between `a.x` and `b.x`, and
  -   * with y-coordiante between `a.y` and `b.y`, both inclusive.
  +   * with y-coordinate between `a.y` and `b.y`, both inclusive.
      *
      * If the distance between `a.x` and `b.x` is not representable
      * (which can happen if one or both is a double),
  
positive.code:    *
     * The rectangle contains the points
     * with x-coordinate between `left` and `left + width`, and
     * with y-coordiante between `top` and `top + height`, both inclusive.
     *
     * The `width` and `height` should be non-negative.
     * If `width` or `height` are negative, they are clamped to zero.
  
negative.code:    *
     * The rectangle contains the points
     * with x-coordinate between `left` and `left + width`, and
     * with y-coordinate between `top` and `top + height`, both inclusive.
     *
     * The `width` and `height` should be non-negative.
     * If `width` or `height` are negative, they are clamped to zero.
  