javascript - 如何在胜利 native 的面积图中制作可拖动光标

注意：我想为react-native提供解决方案。我想在面积图上制作工具提示和可拖动的光标，其中有一条线通过可拖动的光标显示面积图的数据点。我只想标记来自数据集的数据点，而不是标记屏幕触摸点的和y值，触摸屏幕时图形上仅标记x和y值，它给出对应的数据集的最接近值到屏幕。

我在互联网上搜索时发现了类似的内容，但它是用于反应的，并使用了散点图，因为我对胜利本地库非常陌生，而反应本机可以有人告诉如何用面积图将其与反应本机等效。这是我指的链接。

Click me

我只想对胜利中的面积图进行类似的操作，它带有可拖动的光标和工具提示，它们仅在图表坐标上标记数据点，而不在屏幕坐标上标记。

谁能为我提供反应本机代码，如何按照我对胜利区域图的要求，像上面提供的链接一样实现它？
还包括我想转换为react-native的react代码。
拜托，有人，帮帮我。

/* Victory requires `react@^15.5.0` and `prop-types@^15.5.0` */
const {
    VictoryLine, VictoryChart, VictoryCursorContainer, VictoryLabel, VictoryScatter
} = Victory;
const { range, first, last } = _; // lodash
const mountNode = document.getElementById('app');

const allData = range(750).map((x) => ({x, y: x + 30 * Math.random()}));

const findClosestPointSorted = (data, value) => {
    // assumes 3 things:
  // 1. data is sorted by x
  // 2. data points are equally spaced
  // 3. the search is 1-dimentional (x, not x and y)
  if (value === null) return null;
    const start = first(data).x;
    const range = (last(data).x - start);
  const index = Math.round((value - start)/range * (data.length - 1));
  return data[index];
};

class App extends React.Component {
    constructor() {
    super();
    this.state = {
        activePoint: null
    };
  }
    handleCursorChange(value) {
    this.setState({
        activePoint: findClosestPointSorted(allData, value)
    });
  }
  render() {
    const { activePoint } = this.state;
    const point = activePoint ?
        <VictoryScatter data={[activePoint]} style={{data: {size: 100} }}/>
      : null;
    return (
      <div>
        <VictoryChart
          containerComponent={
            <VictoryCursorContainer
              dimension="x"
              onChange={this.handleCursorChange.bind(this)}
              cursorLabel={cursor => `${activePoint.x}, ${Math.round(activePoint.y)}`}
            />
          }
        >
          <VictoryLine data={allData} style={{data: {stroke: '#999'} }}/>
          {point}
        </VictoryChart>
      </div>
    );
  }
}

ReactDOM.render(
    <App/>,
  mountNode
);

最佳答案

import React, { Component } from 'react'
import { Text, StyleSheet, View } from 'react-native'
import {VictoryArea,VictoryChart,createContainer,VictoryTooltip,VictoryScatter,VictoryLine } from 'victory-native';
import {range, first, last,maxBy } from 'lodash';
import Svg,{Line} from 'react-native-svg';

const VictoryZoomVoronoiContainer = createContainer( "cursor","voronoi");

const data = range(20,81).map((x) => ({x, y: x*x}));

const findClosestPointSorted = (data, value) => {
  if (value === null) return null;
    const start = first(data).x;
    const range = (last(data).x - start);
  const index = Math.round((value - start)/range * (data.length - 1));
  return data[index];
};

export default class Chart extends Component {
    componentWillMount()
    {
        this.setState({ymax:maxBy(data,function(o) { return o.y; }).y})
    }

    state = {
        activePoint:null,
        data:data,
        ymax :0
    }
    handleCursorChange(value) {

    this.setState({
        activePoint: findClosestPointSorted(data, value)
    });
  }

    render() {
        const { activePoint } = this.state;
        const point = activePoint ?
            <VictoryScatter name = "scatter" data={[activePoint]} style={{data: {size: 200,fill:'#ffffff',stroke:'#1bad53',strokeWidth:2} }}/>
          : null;

        return (
            <View>
                <VictoryChart
                    height={300}
                    width={350}
                    containerComponent={
                        <VictoryZoomVoronoiContainer
                        voronoiDimension="x"
                        cursorDimension="x"
                        voronoiBlacklist={["scatter"]}
                        labelComponent={<VictoryTooltip style={{fill:'red'}}  flyoutStyle={{
                        fill:  'rgba(52, 52, 52, 0.8)',}}/>}
                        onCursorChange={(value)=>{this.handleCursorChange(value)}}
                        labels={cursor => {

                            try {

                                return(activePoint.x?`${activePoint.x}, ${Math.round(activePoint.y)}\ndjh`:null)
                            } catch (error) {
                                console.log(error)
                            }
                        }}
                        />
                    }
                 >

            <VictoryArea
            name = "area"
            data={data}
            interpolation="cardinal"
            style={{
            data: {
                fill: '#1bad53',
                stroke: '#05a543',
                strokeWidth: 2
            }
            }}
            />
             {point}

          {activePoint?<Line  x1= {50} x2="300" y1={250-(200/this.state.ymax)*activePoint.y} y2={250-(200/this.state.ymax)*activePoint.y} stroke="black" strokeWidth="1"/>:null}

        </VictoryChart>
            </View>
        )
    }
}