Source
static num easeInOutQuartic(num ratio) {
ratio = ratio * 2.0;
return (ratio < 1.0) ? 0.5 * easeInQuartic(ratio) : 0.5 * easeOutQuartic(ratio - 1.0) + 0.5;
}
static num easeInOutQuartic(num ratio) {
ratio = ratio * 2.0;
return (ratio < 1.0) ? 0.5 * easeInQuartic(ratio) : 0.5 * easeOutQuartic(ratio - 1.0) + 0.5;
}