Method readExif

web/js/workflowImage.js:248–269

(reader)

	#start;

	readExif(reader) {
		const TIFF_MARKER = 0x2a;
		const EXIF_IFD = 0x8769;

		this.#reader = reader;
		this.#start = this.#reader.offset;
		this.#readEndianness();

		if (!this.#reader.read(2) === TIFF_MARKER) {
			throw new Error("Invalid TIFF: Marker not found.");
		}

		const dirOffset = this.#reader.read(4);
		this.#reader.seek(this.#start + dirOffset, false);

		for (const t of this.#readTags()) {
			if (t.id === EXIF_IFD) {
				return this.#readExifTag(t);
			}
		}
		throw new Error("No EXIF: TIFF Exif IFD tag not found");
	}

	#readUserComment(tag) {
		this.#reader.seek(this.#start + tag.offset, false);