/// <summary>
/// An <c>CommandDuration</c> runs over a duration of time.
/// </summary>
/// <param name="command">
/// The command to execute. Must be non-null.
/// </param>
/// <param name="duration">
/// The duration of time, in seconds, to apply the command over.
/// Must be greater than or equal to 0.
/// </param>
/// <param name="ease">
/// An easing function to apply to the <c>t</c> parameter of an
/// <c>CommandDuration</c> delegate. If null, linear easing is used.
/// </param>
/// <exception cref="System.ArgumentNullException"></exception>
/// <exception cref="System.ArgumentOutOfRange"></exception>
public static CommandDelegate Duration(CommandDuration command, double duration, CommandEase ease = null)
{
CheckArgumentNonNull(command);
CheckDurationGreaterThanOrEqualToZero(duration);
if (duration == 0.0)
{
// Sometimes it is convenient to create duration commands with
// a time of zero, so we have a special case.
return((ref double deltaTime) =>
{
var t = 1.0;
if (ease != null)
{
t = ease(t);
}
command(t);
return true;
});
}
var elapsedTime = 0.0;
return((ref double deltaTime) =>
{
elapsedTime += deltaTime;
deltaTime = 0.0;
var t = (elapsedTime / duration);
t = t < 0.0 ? 0.0 : (t > 1.0 ? 1.0 : t);
if (ease != null)
{
t = ease(t);
}
command(t);
var finished = elapsedTime >= duration;
if (!finished)
{
return false;
}
deltaTime = elapsedTime - duration;
elapsedTime = 0.0;
return true;
});
}
/// <summary>
/// An <c>CommandDuration</c> runs over a duration of time.
/// </summary>
/// <param name="command">
/// The command to execute. Must be non-null.
/// </param>
/// <param name="duration">
/// The duration of time, in seconds, to apply the command over.
/// Must be greater than or equal to 0.
/// </param>
/// <param name="ease">
/// An easing function to apply to the <c>t</c> parameter of an
/// <c>CommandDuration</c> delegate. If null, linear easing is used.
/// </param>
/// <exception cref="System.ArgumentNullException"></exception>
/// <exception cref="System.ArgumentOutOfRange"></exception>
public static CommandDelegate Duration(CommandDuration command, double duration, CommandEase ease = null)
{
CheckArgumentNonNull(command);
CheckDurationGreaterThanOrEqualToZero(duration);
if (duration == 0.0) {
// Sometimes it is convenient to create duration commands with
// a time of zero, so we have a special case.
return (ref double deltaTime) => {
double t = 1.0;
if (ease != null) { t = ease(t); }
command(t);
return true;
};
}
double elapsedTime = 0.0;
return (ref double deltaTime) => {
elapsedTime += deltaTime;
deltaTime = 0.0;
double t = (elapsedTime / duration);
t = t < 0.0 ? 0.0 : (t > 1.0 ? 1.0 : t);
if (ease != null) { t = ease(t); }
command(t);
bool finished = elapsedTime >= duration;
if (finished) {
deltaTime = elapsedTime - duration;
elapsedTime = 0.0;
}
return finished;
};
}