src/vs/editor/browser/viewParts/lines/viewLine.ts/RenderedViewLine/_readVisibleRangesForRange
class RenderedViewLine:	protected _readVisibleRangesForRange(domNode: FastDomNode<HTMLElement>, lineNumber: number, startColumn: number, endColumn: number, context: DomReadingContext): FloatHorizontalRange[] | null {
		if (startColumn === endColumn) {
			const pixelOffset = this._readPixelOffset(domNode, lineNumber, startColumn, context);
			if (pixelOffset === -1) {
				return null;
			} else {
				return [new FloatHorizontalRange(pixelOffset, 0)];
			}
		} else {
			return this._readRawVisibleRangesForRange(domNode, startColumn, endColumn, context);
		}
	}