src/vs/editor/common/viewLayout/linesLayout.ts/LinesLayout/getVerticalOffsetForWhitespaceIndex
class LinesLayout:	public getVerticalOffsetForWhitespaceIndex(whitespaceIndex: number): number {
		this._checkPendingChanges();
		whitespaceIndex = whitespaceIndex | 0;

		const afterLineNumber = this.getAfterLineNumberForWhitespaceIndex(whitespaceIndex);

		let previousLinesHeight: number;
		if (afterLineNumber >= 1) {
			previousLinesHeight = this._lineHeight * afterLineNumber;
		} else {
			previousLinesHeight = 0;
		}

		let previousWhitespacesHeight: number;
		if (whitespaceIndex > 0) {
			previousWhitespacesHeight = this.getWhitespacesAccumulatedHeight(whitespaceIndex - 1);
		} else {
			previousWhitespacesHeight = 0;
		}
		return previousLinesHeight + previousWhitespacesHeight + this._paddingTop;
	}