code: function maxRadialRadius(context, options) {
      let pxRatio = SmartCanvas.pixelRatio;
  
      if (!context.maxRadius) {
          context.maxRadius = context.max
              - options.borderShadowWidth
              - options.borderOuterWidth * pxRatio
              - options.borderMiddleWidth * pxRatio
              - options.borderInnerWidth * pxRatio
              + (options.borderOuterWidth ? 0.5 : 0)
              + (options.borderMiddleWidth ? 0.5 : 0)
              + (options.borderInnerWidth ? 0.5 : 0);
      }
  
      return context.maxRadius;
  }
docs: /* istanbul ignore next: private, not testable 
  Returns max radius without borders for the gauge
  
  @param {Canvas2DContext} context
  @param {RadialGaugeOptions} options
  @return {number}