src/vs/editor/browser/viewParts/lines/viewLine.ts/DomReadingContext/readClientRect
class DomReadingContext:	private readClientRect(): void {
		if (!this._clientRectRead) {
			this._clientRectRead = true;
			const rect = this._domNode.getBoundingClientRect();
			this._clientRectDeltaLeft = rect.left;
			this._clientRectScale = rect.width / this._domNode.offsetWidth;
		}
	}