private BigInteger getIndex(BigInteger bigStarty, BigDecimal bigHeight, BigInteger numIndexes,
			BigInteger numIndexesMinus1) {
		BigDecimal total = new BigDecimal(bigStarty.multiply(numIndexes));
		BigDecimal div = total.divideToIntegralValue(bigHeight);
		BigInteger index = div.toBigInteger();

		index = index.min(numIndexesMinus1);
		return index;
	}
Get the tooltip for the marker at the specified index and address

@param addr address of item to navigate to
@param x x location of cursor
@param y y location of cursor

@return tool tip string, null if no tool tip
Ghidra/Features/Base/src/main/java/ghidra/app/plugin/core/marker/MarkerSetImpl.java