src/vs/editor/browser/viewParts/lines/viewLine.ts/RenderedViewLine/constructor
class RenderedViewLine:	constructor(domNode: FastDomNode<HTMLElement> | null, renderLineInput: RenderLineInput, characterMapping: CharacterMapping, containsRTL: boolean, containsForeignElements: ForeignElementType) {
		this.domNode = domNode;
		this.input = renderLineInput;
		this._characterMapping = characterMapping;
		this._isWhitespaceOnly = /^\s*$/.test(renderLineInput.lineContent);
		this._containsForeignElements = containsForeignElements;
		this._cachedWidth = -1;

		this._pixelOffsetCache = null;
		if (!containsRTL || this._characterMapping.length === 0 /* the line is empty */) {
			this._pixelOffsetCache = new Float32Array(Math.max(2, this._characterMapping.length + 1));
			for (let column = 0, len = this._characterMapping.length; column <= len; column++) {
				this._pixelOffsetCache[column] = -1;
			}
		}
	}