Method readExif

web/js/workflowImage.js:326–357

* @param {ArrayBuffer} buffer

(buffer)

	 * @param {ArrayBuffer} buffer
	 */
	readExif(buffer) {
		const JPEG_MARKER = 0xffd8;
		const EXIF_SIG = 0x45786966;

		this.#reader = new DataReader(new DataView(buffer));
		if (!this.#reader.read(2) === JPEG_MARKER) {
			throw new Error("Invalid JPEG: SOI not found.");
		}

		const app0 = this.#readAppMarkerId();
		if (app0 !== 0) {
			throw new Error(`Invalid JPEG: APP0 not found [found: ${app0}].`);
		}

		this.#consumeAppSegment();
		const app1 = this.#readAppMarkerId();
		if (app1 !== 1) {
			throw new Error(`No EXIF: APP1 not found [found: ${app0}].`);
		}

		// Skip size
		this.#reader.seek(2);

		if (this.#reader.read(4) !== EXIF_SIG) {
			throw new Error(`No EXIF: Invalid EXIF header signature.`);
		}
		if (this.#reader.read(2) !== 0) {
			throw new Error(`No EXIF: Invalid EXIF header.`);
		}

		return new Tiff().readExif(this.#reader);
	}

	#readAppMarkerId() {
		const APP0_MARKER = 0xffe0;