How to read image into base64 without losing EXIF data?

Question

I'm trying to read one local image created with a different exif.Orientation based on the degrees that it was rotated.

const exifData = piexif.load(data.toString("binary"));

    // Set the desired orientation value in the EXIF data
    exifData["0th"][piexif.ImageIFD.Orientation] = exifOrientation;

    // Encode the modified EXIF data
    const modifiedExifBytes = piexif.dump(exifData);

    // Update the image buffer with the modified EXIF data
    const modifiedImageBuffer = piexif.insert(
      modifiedExifBytes,
      data.toString("binary")
    );

    // Write the modified image buffer to the output file
    const newPath = path.replace("binary.", "binary-rotated.");
    fs.writeFileSync(newPath, modifiedImageBuffer, {
      encoding: "binary",
    });
    const imageFile = fs.readFileSync(newPath);
    const base64Data = Buffer.from(imageFile).toString("base64");

But, my base64Data is constantly losing the EXIF metadata. Can I read it in a different way? I need the base64 encoded with the exif orientation to make an API call.

score 0 · Answer 1 · answered May 26 '23 at 14:33

The intention for this was processing OCR with google vision so was able to workaround this issue by:

Where data is my buffer.

Retrieving EXIF metadata Orientation from the image with piexif

// Reads EXIF data from the file
const exifData = piexif.load(data.toString("binary"));

// Get the angle to rotate the image by its EXIF orientation
// If the image does not have EXIF orientation, will be rotate to 0
let angleToBeRotated = getImageAngle(
 exifData["0th"][piexif.ImageIFD.Orientation]
);

Bake/Burn in image EXIF orientation with piexif

const bakedImageBinary = piexif.remove(data.toString("binary"));

// Write the modified image buffer to the output file
const newPath = path.replace("binary.", "binary-rotated.");
fs.writeFileSync(newPath, bakedImageBinary, {
 encoding: "binary",
});
);

Rotate the image with Jimp to the EXIF orientation

const image = await Jimp.read(newPath);

image.rotate(angleToBeRotated);

image.quality(90);

const base64 = await image.getBase64Async(Jimp.AUTO);

In that way, I can ensure the base64 created is rotated with the correct orientation. Hope this can give a north for anywho in the future. If I manage to find a better way to do that, will update this.

How to read image into base64 without losing EXIF data?

1 Answers1