Reactjs 使用react-chartjs-2,如何使用下载按钮将图表保存为png
我正在尝试使用按钮Onclick下载我的chart.js图表作为png,但我不知道如何实现这一点,我已经完成了这个答案,但对我来说还不够清楚,因为我是chart.js的新手。我不知道如何将这些变量与我的按钮连接起来Reactjs 使用react-chartjs-2,如何使用下载按钮将图表保存为png,reactjs,chart.js,chart.js2,react-chartjs-2,Reactjs,Chart.js,Chart.js2,React Chartjs 2,我正在尝试使用按钮Onclick下载我的chart.js图表作为png,但我不知道如何实现这一点,我已经完成了这个答案,但对我来说还不够清楚,因为我是chart.js的新手。我不知道如何将这些变量与我的按钮连接起来 import React from 'react'; import { Component, useRef } from 'react'; import { Bar } from 'react-chartjs-2'; import 'chartjs-plugin-datalabels
import React from 'react';
import { Component, useRef } from 'react';
import { Bar } from 'react-chartjs-2';
import 'chartjs-plugin-datalabels';
const data = {
labels: ['Finance & Business', 'Mining', 'Community Services', 'Electricity', 'Agriculture', 'Construction', 'Manufacture', "Trade & Tourism", "Transport & Logistics"],
datasets: [
{
label: 'My First dataset',
backgroundColor: ["#3283FC", "", "", "#00C0C8", "#C0BD00", "#3A46B1", "#00A150", "#FEB200", "#9302a1"],
borderWidth: 1,
hoverBackgroundColor: 'rgba(255,99,132,0.4)',
hoverBorderColor: 'rgba(255,99,132,1)',
data: [0.6, 0.0, 0.0, -0.1, -0.1, -0.3, -0.3, -0.6, -1.0],
}
]
};
class StackedBar extends Component {
render() {
return (
<div>
<h2>Bar Example (custom size)</h2>
<Bar
data={data}
options={{
plugins: {
datalabels: {
display: true,
color: '#fff'
}
},
title: {
display: true,
text: 'Contribution Percentage',
position: 'left'
},
maintainAspectRatio: true,
scales: {
xAxes: [{
stacked: true,
gridLines: {
borderDash: [2, 6],
color: "black"
},
scales: {
}
}],
yAxes: [{
ticks: {
beginAtZero: true,
steps: 0.5,
stepSize: 0.5,
max: 1.5,
min: -1.0
},
}]
},
}}
/>
</div>
);
}
}
export default StackedBar;
从“React”导入React;
从“react”导入{Component,useRef};
从'react-chartjs-2'导入{Bar};
导入“chartjs插件数据标签”;
常数数据={
标签:[“金融与商业”、“采矿”、“社区服务”、“电力”、“农业”、“建筑”、“制造”、“贸易与旅游”、“运输与物流”],
数据集:[
{
标签:“我的第一个数据集”,
背景色:[“#3283FC”、“,”、“#00C0C8”、“#C0BD00”、“#3A46B1”、“#00A150”、“#FEB200”、“#9302a1”],
边框宽度:1,
hoverBackgroundColor:'rgba(255,99132,0.4)',
hoverBorderColor:'rgba(255,99132,1)',
数据:[0.6,0.0,0.0,-0.1,-0.1,-0.3,-0.3,-0.6,-1.0],
}
]
};
类StackedBar扩展组件{
render(){
返回(
条形图示例(自定义尺寸)
);
}
}
导出默认StackedBar;
所以我安装了一个名为FileSave.js的插件//
npm安装
npm i文件保护程序
导入插件
从“文件保护程序”导入{saveAs}代码>
而不仅仅是编写这个blob函数
类StackedBar扩展组件{
saveCanvas(){
//保存到png
const canvasSave=document.getElementById('stackD');
canvasSave.toBlob(函数(blob){
saveAs(blob,“testing.png”)
})
}
render(){
返回(
下载为PNG
);
}
}
导出默认StackedBar;
另一个选项是使用chart ref,然后使用chart.js toBase64Image函数。将其另存为base64,转换为blob并使用文件保护程序包另存为文件
import { saveAs } from 'file-saver';
/**
* @param b64Data
* @param contentType
* @param sliceSize
* @returns {Blob}
* @link https://stackoverflow.com/questions/16245767/creating-a-blob-from-a-base64-string-in-javascript
*/
const b64toBlob = (b64Data, contentType = '', sliceSize = 512) => {
const byteCharacters = atob(b64Data);
const byteArrays = [];
for (let offset = 0; offset < byteCharacters.length; offset += sliceSize) {
const slice = byteCharacters.slice(offset, offset + sliceSize);
const byteNumbers = new Array(slice.length);
// eslint-disable-next-line no-plusplus
for (let i = 0; i < slice.length; i += 1) {
byteNumbers[i] = slice.charCodeAt(i);
}
const byteArray = new Uint8Array(byteNumbers);
byteArrays.push(byteArray);
}
return new Blob(byteArrays, { type: contentType });
};
... in component
const chartRef = useRef(null);
... in jsx...
<Button
onClick={() => {
const b64 = chartRef.current.toBase64Image().replace('data:image/png;base64,', '');
const content = b64toBlob(b64);
const file = new File([content], 'Revenue_chart.png', { type: 'image/png' });
saveAs(file);
}}
>
img
</Button>
<Line data={data} options={options} ref={chartRef} />
从“文件保护程序”导入{saveAs};
/**
*@param b64Data
*@param contentType
*@param切片大小
*@returns{Blob}
*@linkhttps://stackoverflow.com/questions/16245767/creating-a-blob-from-a-base64-string-in-javascript
*/
const b64toBlob=(b64Data,contentType='',sliceSize=512)=>{
常量ByTechCharacters=atob(B64数据);
常量字节数组=[];
for(让offset=0;offset
img
import { saveAs } from 'file-saver';
/**
* @param b64Data
* @param contentType
* @param sliceSize
* @returns {Blob}
* @link https://stackoverflow.com/questions/16245767/creating-a-blob-from-a-base64-string-in-javascript
*/
const b64toBlob = (b64Data, contentType = '', sliceSize = 512) => {
const byteCharacters = atob(b64Data);
const byteArrays = [];
for (let offset = 0; offset < byteCharacters.length; offset += sliceSize) {
const slice = byteCharacters.slice(offset, offset + sliceSize);
const byteNumbers = new Array(slice.length);
// eslint-disable-next-line no-plusplus
for (let i = 0; i < slice.length; i += 1) {
byteNumbers[i] = slice.charCodeAt(i);
}
const byteArray = new Uint8Array(byteNumbers);
byteArrays.push(byteArray);
}
return new Blob(byteArrays, { type: contentType });
};
... in component
const chartRef = useRef(null);
... in jsx...
<Button
onClick={() => {
const b64 = chartRef.current.toBase64Image().replace('data:image/png;base64,', '');
const content = b64toBlob(b64);
const file = new File([content], 'Revenue_chart.png', { type: 'image/png' });
saveAs(file);
}}
>
img
</Button>
<Line data={data} options={options} ref={chartRef} />