cytoscape save graph as image by button

Question

I saw in the cytoscape.js tutorial that there are ways to represent the graph as image (png, jpg), but there is a way to represent it as regular graph, and if the user would want he can save it as image by click on button or similar option?

Didn't find simple way for that.

I am using python flask as my server side and cytoscape js for the graphes.

Panathenaea

Answer 1

You don't need server side code to save files from the browser anymore.

You can save files using the saveAs() API in JS. Here's a polyfill: https://github.com/eligrey/FileSaver.js/

If you want the graph data, it would just be

var jsonBlob = new Blob([ JSON.stringify( cy.json() ) ], { type: 'application/javascript;charset=utf-8' });

saveAs( jsonBlob, 'graph.json' );

Or for images

var b64key = 'base64,';
var b64 = cy.png().substring( content.indexOf(b64key) + b64key.length );
var imgBlob = base64ToBlob( b64, 'image/png' );

saveAs( imgBlob, 'graph.png' );

(Refer to other question re. base64toBlob())

Furred

Thank, its work with tiny change, i replace the scondeline with this: 'var b64 = cy.png().substring( cy.png().indexOf(b64key) + b64key.length );' i.e before this little change the "content" was not define and it throw error. – Panathenaea

For more info, you can export as jpg, png, or json with numerous options: js.cytoscape.org/#core/export – Bedbug

Answer 2

Improving the answer marked as correct:

You can use saveAs() directly, simply do:

import { saveAs } from "file-saver"; //or require
...
saveAs(cy.png(), "graph.png");

No need to handle blob content, same goes for .jpg()

Adorne

Thank you. This should be included in "marked as correct" – Rittenhouse

npmjs.com/package/file-saver – Rittenhouse

Answer 3

If you want a solution without further library usage, here an idea:

const pngBlob = await cy.png({
  output: 'blob-promise',
});

const fileName = 'myfile.png';
const downloadLink = document.createElement('a');
downloadLink.href = URL.createObjectURL(pngBlob);
downloadLink.download = fileName;
downloadLink.click();

Note that the output property of the png() function parameter can be used to directly generate a Blob object. If you use the value blob-promise the function returns a promise instead of a blog directly, so you can keep your UI non-blocking.

See the official cytoscape docs for more details.

Aunt