Skip to content

Instantly share code, notes, and snippets.

Embed
What would you like to do?
copy EXIF from one JPEG blob to another and return a new JPEG blob.
// Copyright (c) 2019 Jian Weihang <tonytonyjan@gmail.com>
export default async (src, dest) => {
const exif = await retrieveExif(src);
return new Blob([dest.slice(0, 2), exif, dest.slice(2)], {
type: "image/jpeg"
});
};
export const SOS = 0xffda,
APP1 = 0xffe1,
EXIF = 0x45786966,
retrieveExif = blob =>
new Promise((resolve, reject) => {
const reader = new FileReader();
reader.addEventListener("load", ({ target: { result: buffer } }) => {
const view = new DataView(buffer);
let offset = 0;
if (view.getUint16(offset) !== 0xffd8)
return reject("not a valid jpeg");
offset += 2;
while (true) {
const marker = view.getUint16(offset);
if (marker === SOS) break;
const size = view.getUint16(offset + 2);
if (marker === APP1 && view.getUint32(offset + 4) === EXIF)
return resolve(blob.slice(offset, offset + 2 + size));
offset += 2 + size;
}
return resolve(new Blob());
});
reader.readAsArrayBuffer(blob);
});
@boustanihani
Copy link

boustanihani commented Jun 23, 2021

Cool work, is there also a way to copy IPTC, XMP, or simply any kind of metadata from one JPG to another? Best regards.

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment