/// <summary>
/// Calculates the value this animation believes should be the current value for the property.
/// </summary>
/// <param name="defaultOriginValue">
/// This value is the suggested origin value provided to the animation
/// to be used if the animation does not have its own concept of a
/// start value. If this animation is the first in a composition chain
/// this value will be the snapshot value if one is available or the
/// base property value if it is not; otherise this value will be the
/// value returned by the previous animation in the chain with an
/// animationClock that is not Stopped.
/// </param>
/// <param name="defaultDestinationValue">
/// This value is the suggested destination value provided to the animation
/// to be used if the animation does not have its own concept of an
/// end value. This value will be the base value if the animation is
/// in the first composition layer of animations on a property;
/// otherwise this value will be the output value from the previous
/// composition layer of animations for the property.
/// </param>
/// <param name="animationClock">
/// This is the animationClock which can generate the CurrentTime or
/// CurrentProgress value to be used by the animation to generate its
/// output value.
/// </param>
/// <returns>
/// The value this animation believes should be the current value for the property.
/// </returns>
protected sealed override Byte GetCurrentValueCore(
Byte defaultOriginValue,
Byte defaultDestinationValue,
AnimationClock animationClock)
{
Debug.Assert(animationClock.CurrentState != ClockState.Stopped);
if (_keyFrames == null)
{
return(defaultDestinationValue);
}
// We resolved our KeyTimes when we froze, but also got notified
// of the frozen state and therefore invalidated ourselves.
if (!_areKeyTimesValid)
{
ResolveKeyTimes();
}
if (_sortedResolvedKeyFrames == null)
{
return(defaultDestinationValue);
}
TimeSpan currentTime = animationClock.CurrentTime.Value;
Int32 keyFrameCount = _sortedResolvedKeyFrames.Length;
Int32 maxKeyFrameIndex = keyFrameCount - 1;
Byte currentIterationValue;
Debug.Assert(maxKeyFrameIndex >= 0, "maxKeyFrameIndex is less than zero which means we don't actually have any key frames.");
Int32 currentResolvedKeyFrameIndex = 0;
// Skip all the key frames with key times lower than the current time.
// currentResolvedKeyFrameIndex will be greater than maxKeyFrameIndex
// if we are past the last key frame.
while (currentResolvedKeyFrameIndex < keyFrameCount &&
currentTime > _sortedResolvedKeyFrames[currentResolvedKeyFrameIndex]._resolvedKeyTime)
{
currentResolvedKeyFrameIndex++;
}
// If there are multiple key frames at the same key time, be sure to go to the last one.
while (currentResolvedKeyFrameIndex < maxKeyFrameIndex &&
currentTime == _sortedResolvedKeyFrames[currentResolvedKeyFrameIndex + 1]._resolvedKeyTime)
{
currentResolvedKeyFrameIndex++;
}
if (currentResolvedKeyFrameIndex == keyFrameCount)
{
// Past the last key frame.
currentIterationValue = GetResolvedKeyFrameValue(maxKeyFrameIndex);
}
else if (currentTime == _sortedResolvedKeyFrames[currentResolvedKeyFrameIndex]._resolvedKeyTime)
{
// Exactly on a key frame.
currentIterationValue = GetResolvedKeyFrameValue(currentResolvedKeyFrameIndex);
}
else
{
// Between two key frames.
Double currentSegmentProgress = 0.0;
Byte fromValue;
if (currentResolvedKeyFrameIndex == 0)
{
// The current key frame is the first key frame so we have
// some special rules for determining the fromValue and an
// optimized method of calculating the currentSegmentProgress.
// If we're additive we want the base value to be a zero value
// so that if there isn't a key frame at time 0.0, we'll use
// the zero value for the time 0.0 value and then add that
// later to the base value.
if (IsAdditive)
{
fromValue = AnimatedTypeHelpers.GetZeroValueByte(defaultOriginValue);
}
else
{
fromValue = defaultOriginValue;
}
// Current segment time divided by the segment duration.
// Note: the reason this works is that we know that we're in
// the first segment, so we can assume:
//
// currentTime.TotalMilliseconds = current segment time
// _sortedResolvedKeyFrames[0]._resolvedKeyTime.TotalMilliseconds = current segment duration
currentSegmentProgress = currentTime.TotalMilliseconds
/ _sortedResolvedKeyFrames[0]._resolvedKeyTime.TotalMilliseconds;
}
else
{
Int32 previousResolvedKeyFrameIndex = currentResolvedKeyFrameIndex - 1;
TimeSpan previousResolvedKeyTime = _sortedResolvedKeyFrames[previousResolvedKeyFrameIndex]._resolvedKeyTime;
fromValue = GetResolvedKeyFrameValue(previousResolvedKeyFrameIndex);
TimeSpan segmentCurrentTime = currentTime - previousResolvedKeyTime;
TimeSpan segmentDuration = _sortedResolvedKeyFrames[currentResolvedKeyFrameIndex]._resolvedKeyTime - previousResolvedKeyTime;
currentSegmentProgress = segmentCurrentTime.TotalMilliseconds
/ segmentDuration.TotalMilliseconds;
}
currentIterationValue = GetResolvedKeyFrame(currentResolvedKeyFrameIndex).InterpolateValue(fromValue, currentSegmentProgress);
}
// If we're cumulative, we need to multiply the final key frame
// value by the current repeat count and add this to the return
// value.
if (IsCumulative)
{
Double currentRepeat = (Double)(animationClock.CurrentIteration - 1);
if (currentRepeat > 0.0)
{
currentIterationValue = AnimatedTypeHelpers.AddByte(
currentIterationValue,
AnimatedTypeHelpers.ScaleByte(GetResolvedKeyFrameValue(maxKeyFrameIndex), currentRepeat));
}
}
// If we're additive we need to add the base value to the return value.
if (IsAdditive)
{
return(AnimatedTypeHelpers.AddByte(defaultOriginValue, currentIterationValue));
}
return(currentIterationValue);
}
/// <summary>
/// Calculates the value this animation believes should be the current value for the property.
/// </summary>
/// <param name="defaultOriginValue">
/// This value is the suggested origin value provided to the animation
/// to be used if the animation does not have its own concept of a
/// start value. If this animation is the first in a composition chain
/// this value will be the snapshot value if one is available or the
/// base property value if it is not; otherise this value will be the
/// value returned by the previous animation in the chain with an
/// animationClock that is not Stopped.
/// </param>
/// <param name="defaultDestinationValue">
/// This value is the suggested destination value provided to the animation
/// to be used if the animation does not have its own concept of an
/// end value. This value will be the base value if the animation is
/// in the first composition layer of animations on a property;
/// otherwise this value will be the output value from the previous
/// composition layer of animations for the property.
/// </param>
/// <param name="animationClock">
/// This is the animationClock which can generate the CurrentTime or
/// CurrentProgress value to be used by the animation to generate its
/// output value.
/// </param>
/// <returns>
/// The value this animation believes should be the current value for the property.
/// </returns>
protected override Byte GetCurrentValueCore(Byte defaultOriginValue, Byte defaultDestinationValue, AnimationClock animationClock)
{
Debug.Assert(animationClock.CurrentState != ClockState.Stopped);
if (!_isAnimationFunctionValid)
{
ValidateAnimationFunction();
}
double progress = animationClock.CurrentProgress.Value;
IEasingFunction easingFunction = EasingFunction;
if (easingFunction != null)
{
progress = easingFunction.Ease(progress);
}
Byte from = new Byte();
Byte to = new Byte();
Byte accumulated = new Byte();
Byte foundation = new Byte();
// need to validate the default origin and destination values if
// the animation uses them as the from, to, or foundation values
bool validateOrigin = false;
bool validateDestination = false;
switch (_animationType)
{
case AnimationType.Automatic:
from = defaultOriginValue;
to = defaultDestinationValue;
validateOrigin = true;
validateDestination = true;
break;
case AnimationType.From:
from = _keyValues[0];
to = defaultDestinationValue;
validateDestination = true;
break;
case AnimationType.To:
from = defaultOriginValue;
to = _keyValues[0];
validateOrigin = true;
break;
case AnimationType.By:
// According to the SMIL specification, a By animation is
// always additive. But we don't force this so that a
// user can re-use a By animation and have it replace the
// animations that precede it in the list without having
// to manually set the From value to the base value.
to = _keyValues[0];
foundation = defaultOriginValue;
validateOrigin = true;
break;
case AnimationType.FromTo:
from = _keyValues[0];
to = _keyValues[1];
if (IsAdditive)
{
foundation = defaultOriginValue;
validateOrigin = true;
}
break;
case AnimationType.FromBy:
from = _keyValues[0];
to = AnimatedTypeHelpers.AddByte(_keyValues[0], _keyValues[1]);
if (IsAdditive)
{
foundation = defaultOriginValue;
validateOrigin = true;
}
break;
default:
Debug.Fail("Unknown animation type.");
break;
}
if (validateOrigin &&
!AnimatedTypeHelpers.IsValidAnimationValueByte(defaultOriginValue))
{
throw new InvalidOperationException(
SR.Get(
SRID.Animation_Invalid_DefaultValue,
this.GetType(),
"origin",
defaultOriginValue.ToString(CultureInfo.InvariantCulture)));
}
if (validateDestination &&
!AnimatedTypeHelpers.IsValidAnimationValueByte(defaultDestinationValue))
{
throw new InvalidOperationException(
SR.Get(
SRID.Animation_Invalid_DefaultValue,
this.GetType(),
"destination",
defaultDestinationValue.ToString(CultureInfo.InvariantCulture)));
}
if (IsCumulative)
{
double currentRepeat = (double)(animationClock.CurrentIteration - 1);
if (currentRepeat > 0.0)
{
Byte accumulator = AnimatedTypeHelpers.SubtractByte(to, from);
accumulated = AnimatedTypeHelpers.ScaleByte(accumulator, currentRepeat);
}
}
// return foundation + accumulated + from + ((to - from) * progress)
return(AnimatedTypeHelpers.AddByte(
foundation,
AnimatedTypeHelpers.AddByte(
accumulated,
AnimatedTypeHelpers.InterpolateByte(from, to, progress))));
}