Is it possible to generate images from polotno JSON on the backend?
Yes, you can leverage a polotno-node package.
Using polotno-node
you can use most of Polotno Store API. The common usage is image export from Polotno JSON:
const fs = require('fs');
// import polotno-node API
const { createInstance } = require('polotno-node');
async function run() {
// create working instance
const instance = await createInstance({
// to create your own API key please go here: https://polotno.com/cabinet
key: 'nFA5H9elEytDyPyvKL7T',
});
// load sample json
const json = JSON.parse(fs.readFileSync('polotno.json'));
// here you can manipulate JSON somehow manually
// for example replace some images or change text
// then we can convert json into image
const imageBase64 = await instance.jsonToImageBase64(json); // by default it will be png image
// write image into local file
fs.writeFileSync('out.png', imageBase64, 'base64');
// also we can export design into lower size
// and change image type
const jpegImage = await instance.jsonToImageBase64(json, {
pixelRatio: 0.5, // make image twice smaller
mimeType: 'image/jpeg',
});
fs.writeFileSync('out.jpg', jpegImage, 'base64');
// close instance
instance.close();
}
run();