private void UpdateParameters()
{
// If we're currently at rest, start the timer.
if (_atRest)
{
_ticks = Environment.TickCount;
}
_depTargetValue.OnGet();
if (!_initialized)
{
// Start at the target value.
_targetTicks = _ticks;
_a = 1.0F;
_c = _targetValue;
_initialized = true;
}
else if (!_hasInertia)
{
// Fix at the target value.
_targetTicks = _ticks;
_a = 1.0F;
_c = _targetValue;
}
else if (_c != _targetValue)
{
// Get the starting state using the previous parameters.
float y0;
float yp0;
long relativeToEnd = unchecked (_ticks - _targetTicks);
if (relativeToEnd < 0)
{
float x = relativeToEnd * SPEED;
y0 = _a * (2.0F * x + 3.0F) * x * x + _c;
yp0 = _a * (6.0F * x + 6.0F) * x;
}
else
{
y0 = _c;
yp0 = 0.0F;
}
// Calculate the parameters of the curve based on the target value.
float x0 = -1.0F;
if (Math.Abs(yp0) > EPSILON)
{
float t = 6.0F * (y0 - _targetValue) / yp0; // Temporary
float d = (float)Math.Sqrt((t + 2.0F) * t + 9.0F); // Square root of discriminant
float c = (t - 3.0F + d) / 4.0F; // Larger candidate root.
// x0 must be negative. If larger candidate is negative, use it. Otherwise, use smaller one.
x0 = (c < 0.0F) ? c : ((t - 3.0F - d) / 4.0F);
}
_a = (y0 - _targetValue) / ((2.0F * x0 + 3.0F) * x0 * x0);
_c = _targetValue;
_targetTicks = unchecked (_ticks - (long)(x0 / SPEED));
}
_atRest = false;
}
private void UpdateNow()
{
if (_running)
{
_computed.OnGet();
}
}
private void UpdateValue()
{
_depParameters.OnGet();
if (!_atRest)
{
// Calculate the current value based on the current time and the parameters of the curve.
_dynTicks.OnGet();
long relativeToEnd = unchecked (_ticks - _targetTicks);
if (relativeToEnd >= 0)
{
// We've reached the target. Stop moving.
_atRest = true;
_value = _c;
}
else
{
// Determine the current position based on how much time is left.
float x = relativeToEnd * SPEED;
_value = _a * (2.0F * x + 3.0F) * x * x + _c;
}
}
}
private void UpdateNow()
{
_depCollection.OnGet();
}
public bool CanExecute(object parameter)
{
// Just returning the flag. The flag gets set elsewhere.
_depCanExecute.OnGet();
return(_canExecute);
}