Recharts component to PNG

Question

I currently have a Recharts component that I would like to export as a PNG file.

<LineChart
  id="currentChart"
  ref={(chart) => (this.currentChart = chart)}
  width={this.state.width}
  height={this.state.height}
  data={this.testData}
  margin={{ top: 5, right: 30, left: 20, bottom: 5 }}
>
  <XAxis dataKey="name" />
  <YAxis />
  <CartesianGrid strokeDasharray="3 3" />
  <Tooltip />
  <Legend />
  <Line type="monotone" dataKey="pv" stroke="#8884d8" activeDot={{ r: 8 }} />
  <Line type="monotone" dataKey="uv" stroke="#82ca9d" />
</LineChart>;

but I'm unsure if this is directly supported by the library.

I have an idea that involves using a canvas and a 2D rendering context to get me close to a solution, as outlined on MDN

However, I'm not sure of a generic way to render an HTML element (or React Component) as a canvas to implement this solution.

I might be going about this all wrong, and I would appreciate the correction!

score 11 · Answer 1 · answered May 20 '19 at 14:33

This function takes SVG element on input and transforms to image/png data:

export const svgToPng = (svg, width, height) => {

    return new Promise((resolve, reject) => {

        let canvas = document.createElement('canvas');
        canvas.width = width;
        canvas.height = height;
        let ctx = canvas.getContext('2d');

        // Set background to white
        ctx.fillStyle = '#ffffff';
        ctx.fillRect(0, 0, width, height);

        let xml = new XMLSerializer().serializeToString(svg);
        let dataUrl = 'data:image/svg+xml;utf8,' + encodeURIComponent(xml);
        let img = new Image(width, height);

        img.onload = () => {
            ctx.drawImage(img, 0, 0);
            let imageData = canvas.toDataURL('image/png', 1.0);
            resolve(imageData)
        }

        img.onerror = () => reject();

        img.src = dataUrl;
    });
};

And how to access the Recharts SVG element? This code snippet allows you to render any Chart outside of your current visible DOM and use it's SVG:

const exportChart = () => {

    // Output image size
    const WIDTH = 900;
    const HEIGHT = 250;

    const convertChart = async (ref) => {

        if (ref && ref.container) {
            let svg = ref.container.children[0];
            let pngData = await svgToPng(svg, WIDTH, HEIGHT);
            console.log('Do what you need with PNG', pngData);
        }
    };

    const chart = <LineChart data={...} width={WIDTH} height={HEIGHT}
        ref={ref => convertChart(ref)} />;

    // Render chart component into helper div
    const helperDiv = document.createElement('tmp');
    ReactDOM.render(chart, helperDiv);
}

I can't create a blob using the pngData, any help on that? I need the blob so that I can download the png image — AlbertMunichMar, Jul 25 '19 at 11:30
@AlbertMunichMar I believe, you can try to modify the solution by downloading the pdf image from canvas. See here: https://stackoverflow.com/questions/8126623/downloading-canvas-element-to-an-image — peter.bartos, Jul 25 '19 at 14:02

score 9 · Accepted Answer · answered Jul 13 '17 at 20:26

9

I was able to solve my problem by delving into the Recharts component. Recharts renders as an SVG under a wrapper so all I had to do was convert properly to save as both HTML or SVG

// Exports the graph as embedded JS or PNG
exportChart(asSVG) {

    // A Recharts component is rendered as a div that contains namely an SVG
    // which holds the chart. We can access this SVG by calling upon the first child/
    let chartSVG = ReactDOM.findDOMNode(this.currentChart).children[0];

    if (asSVG) {
        let svgURL = new XMLSerializer().serializeToString(chartSVG);
        let svgBlob = new Blob([svgURL], {type: "image/svg+xml;charset=utf-8"});
        FileSaver.saveAs(svgBlob, this.state.uuid + ".svg");
    } else {
        let svgBlob = new Blob([chartSVG.outerHTML], {type: "text/html;charset=utf-8"});
        FileSaver.saveAs(svgBlob, this.state.uuid + ".html");
    }
}

I am using FileSaver.js for the save prompt.

answered Jul 13 '17 at 20:26

Cole

2,601
1
15
32

Hi, what is `currentChart` here? – Bajal Sep 11 '18 at 14:55
Hi, @Bajal `ref={(chart) => this.currentChart = chart}` – Yura Zatsepin Sep 12 '18 at 13:25
7

Where do you convert the svg to png? – Qwerty Nov 27 '18 at 16:48
Is this possible to add a codepen, jsfiddle to have a full picture of current example? – Kashif Ullah Jan 16 '19 at 05:13
Any way to convert the svg to png – Cristiano Coelho Jun 14 '21 at 20:03

score 3 · Answer 3 · answered Sep 09 '20 at 12:03

3

@brammitch created a package for this (inspired by answers here):

https://github.com/brammitch/recharts-to-png

answered Sep 09 '20 at 12:03

Fabio Espinosa

708
5
13

score 2 · Answer 4 · answered Jan 12 '21 at 20:52

The written answer helped me a lot. Many thanks for that. Nevertheless, I was missing an "out of the box" solution for the download as png, which I would like to make up for here. Even if it's too late, maybe it will help someone else.

handleExportChart = () => {

        let chartSVG = ReactDOM.findDOMNode(this.currentChart).children[0];
        const width = chartSVG.clientWidth;
        const height = chartSVG.clientHeight;
        let svgURL = new XMLSerializer().serializeToString(chartSVG);
        let svgBlob = new Blob([svgURL], { type: "image/svg+xml;charset=utf-8" });
        let URL = window.URL || window.webkitURL || window;
        let blobURL = URL.createObjectURL(svgBlob);

        let image = new Image();
        image.onload = () => {
            let canvas = document.createElement('canvas');
            canvas.width = width;
            canvas.height = height;
            let context = canvas.getContext('2d');
            context.drawImage(image, 0, 0, context.canvas.width, context.canvas.height);
            let png = canvas.toDataURL('image/png', 1.0);
            FileSaver.saveAs(png, "Test.png");
        };

        image.src = blobURL;
    };

score 0 · Answer 5 · answered Jan 19 '21 at 18:31

0

This is an old post but this might help someone

let pngData = await getPngData(this.ref);
FileSaver.saveAs(pngData, filename);

using recharts-to-png and file-saver npm modules

answered Jan 19 '21 at 18:31

Maya Ben

147
2
11

Recharts component to PNG

5 Answers5

Linked