我应该让我的计算函数保持未定义状态吗—不在类中吗？

如何解决我应该让我的计算函数保持未定义状态吗—不在类中吗？

我在CoverContainer中放置了一个lib/widgets/cover_container.dart小部件，需要这些双精度值：

• coverHeight(context)
• completeBlur(context)
• opacity(context)
• increaseColorLightness(color)

目前，我在这样的单独.dart文件中具有这些功能：

import 'package:flutter/material.dart';
import 'package:chefmenu2/theme/style_constants.dart';
import 'my_scroll_position.dart';
import 'package:provider/provider.dart';
import 'dart:math';

// scroll: ~160
double backLayerAnimationBottomPoint(BuildContext context) =>
    MediaQuery.of(context).size.height * kCoverHeightProportion - kBigBoxPadding - bottomTopPointsdiff(context);

// scroll: ~240
double backLayerAnimationTopPoint(BuildContext context) => MediaQuery.of(context).size.height * kCoverHeightProportion - kBigBoxPadding;

// delta btw Top and Bottom points
double bottomTopPointsdiff(BuildContext context) => anchor(context) / 3.5 * MediaQuery.of(context).size.height;

// default cover height before we start scrolling
double defaultCoverHeight(BuildContext context) => (MediaQuery.of(context).size.height) * kCoverHeightProportion + kBigBoxPadding;

// once we reach the bottom point,the cover starts growing according to this formula
double growingCoverHeight(BuildContext context) =>
    defaultCoverHeight(context) + Provider.of<MyScrollPosition>(context).data - backLayerAnimationBottomPoint(context);

double coverHeight(BuildContext context) => Provider.of<MyScrollPosition>(context).data < backLayerAnimationBottomPoint(context)
    ? defaultCoverHeight(context)
    : Provider.of<MyScrollPosition>(context).data < MediaQuery.of(context).size.height
        ? growingCoverHeight(context) // this is the formula
        : MediaQuery.of(context).size.height;

double completeBlur(BuildContext context) => Provider.of<MyScrollPosition>(context).data < backLayerAnimationTopPoint(context)
    ? blur(context,firstPhaseBlur(context))
    : blur(context,finalPhaseMaxBlur(context));

double blur(BuildContext context,double getFunction) =>
    // handles exception: blur boundary < 0
    Provider.of<MyScrollPosition>(context).data < backLayerAnimationBottomPoint(context) ? 0 : getFunction;

double firstPhaseBlur(BuildContext context) =>
    pow((Provider.of<MyScrollPosition>(context).data - backLayerAnimationBottomPoint(context)) * kBlurSpeed,kExponent);

double finalPhaseMaxBlur(BuildContext context) => pow(bottomTopPointsdiff(context) * kBlurSpeed,kExponent);

double opacity(BuildContext context) =>
    // handles exceptions: opacity boundary < 0 && opacity bouandary > 1
    completeOpacity(context) < 0 ? 0 : completeOpacity(context) > 1 ? 1 : completeOpacity(context);

double completeOpacity(BuildContext context) => Provider.of<MyScrollPosition>(context).data < backLayerAnimationTopPoint(context)
    ? kCoverColorOpacityCoefficient * blur(context,firstPhaseBlur(context))
    : kCoverColorOpacityCoefficient * blur(context,finalPhaseMaxBlur(context));

Color increaseColorLightness(Color color) => HSVColor.fromColor(color).withValue(0.9).toColor();

double restaurantTitleTopPadding(BuildContext context) =>
    kCoverHeightProportion * MediaQuery.of(context).size.height - kRestaurantTitleMaxShadowBlur * 2;

我的工作方式有效，但是这可能不是最佳方法。根据官方dart guidelines的说法：

” Dart不需要在类内定义所有代码-您可以像使用过程语言或函数语言一样定义顶级变量，常量和函数。 “

另一方面，他们也说：

” 从未实例化的类型是代码气味。但是，这不是硬性规定。 “

正确的方法是什么？这些计算应放在何处以及如何放置（在班级中或现在）？