StyleValue styleDenominator = styleFraction.getDenominator();
if ((styleNumerator instanceof StyleLength) &&
(styleDenominator instanceof StyleTime)) {
StyleLength styleLength = (StyleLength) styleNumerator;
StyleTime styleTime = (StyleTime) styleDenominator;
// Convert time to seconds.
double timeInSeconds = timeConverter.convert(styleTime.getNumber(), styleTime.getUnit(), TimeUnit.S);
// If conversion succeded...
if (!Double.isNaN(timeInSeconds)) {
// Return speed in em/sec.
if (styleLength.getUnit() == LengthUnit.EM) {