private static bool TryInterpolate(TransformOperations from, TransformOperations to, double progress, ref TransformOperations result)
{
bool fromIdentity = from.IsIdentity;
bool toIdentity = to.IsIdentity;
if (fromIdentity && toIdentity)
{
return(true);
}
int matchingPrefixLength = ComputeMatchingPrefixLength(from, to);
int fromSize = fromIdentity ? 0 : from._operations.Count;
int toSize = toIdentity ? 0 : to._operations.Count;
int numOperations = Math.Max(fromSize, toSize);
var builder = new Builder(matchingPrefixLength);
for (int i = 0; i < matchingPrefixLength; i++)
{
TransformOperation interpolated = new TransformOperation
{
Type = TransformOperation.OperationType.Identity
};
if (!TransformOperation.TryInterpolate(
i >= fromSize ? default(TransformOperation?) : from._operations[i],
i >= toSize ? default(TransformOperation?) : to._operations[i],
progress,
ref interpolated))
{
return(false);
}
builder.Append(interpolated);
}
if (matchingPrefixLength < numOperations)
{
if (!ComputeDecomposedTransform(from, matchingPrefixLength, out Matrix.Decomposed fromDecomposed) ||
!ComputeDecomposedTransform(to, matchingPrefixLength, out Matrix.Decomposed toDecomposed))
{
return(false);
}
var transform = InterpolationUtilities.InterpolateDecomposedTransforms(ref fromDecomposed, ref toDecomposed, progress);
builder.AppendMatrix(InterpolationUtilities.ComposeTransform(transform));
}
result = builder.Build();
return(true);
}
/// <summary>
/// Attempts to interpolate between two transform operations.
/// </summary>
/// <param name="from">Source operation.</param>
/// <param name="to">Target operation.</param>
/// <param name="progress">Interpolation progress.</param>
/// <param name="result">Interpolation result that will be filled in when operation was successful.</param>
/// <remarks>
/// Based upon https://www.w3.org/TR/css-transforms-1/#interpolation-of-transform-functions.
/// </remarks>
public static bool TryInterpolate(TransformOperation?from, TransformOperation?to, double progress,
ref TransformOperation result)
{
bool fromIdentity = IsOperationIdentity(ref from);
bool toIdentity = IsOperationIdentity(ref to);
if (fromIdentity && toIdentity)
{
return(true);
}
// ReSharper disable PossibleInvalidOperationException
TransformOperation fromValue = fromIdentity ? Identity : from.Value;
TransformOperation toValue = toIdentity ? Identity : to.Value;
// ReSharper restore PossibleInvalidOperationException
var interpolationType = toIdentity ? fromValue.Type : toValue.Type;
result.Type = interpolationType;
switch (interpolationType)
{
case OperationType.Translate:
{
double fromX = fromIdentity ? 0 : fromValue.Data.Translate.X;
double fromY = fromIdentity ? 0 : fromValue.Data.Translate.Y;
double toX = toIdentity ? 0 : toValue.Data.Translate.X;
double toY = toIdentity ? 0 : toValue.Data.Translate.Y;
result.Data.Translate.X = InterpolationUtilities.InterpolateScalars(fromX, toX, progress);
result.Data.Translate.Y = InterpolationUtilities.InterpolateScalars(fromY, toY, progress);
result.Bake();
break;
}
case OperationType.Rotate:
{
double fromAngle = fromIdentity ? 0 : fromValue.Data.Rotate.Angle;
double toAngle = toIdentity ? 0 : toValue.Data.Rotate.Angle;
result.Data.Rotate.Angle = InterpolationUtilities.InterpolateScalars(fromAngle, toAngle, progress);
result.Bake();
break;
}
case OperationType.Scale:
{
double fromX = fromIdentity ? 1 : fromValue.Data.Scale.X;
double fromY = fromIdentity ? 1 : fromValue.Data.Scale.Y;
double toX = toIdentity ? 1 : toValue.Data.Scale.X;
double toY = toIdentity ? 1 : toValue.Data.Scale.Y;
result.Data.Scale.X = InterpolationUtilities.InterpolateScalars(fromX, toX, progress);
result.Data.Scale.Y = InterpolationUtilities.InterpolateScalars(fromY, toY, progress);
result.Bake();
break;
}
case OperationType.Skew:
{
double fromX = fromIdentity ? 0 : fromValue.Data.Skew.X;
double fromY = fromIdentity ? 0 : fromValue.Data.Skew.Y;
double toX = toIdentity ? 0 : toValue.Data.Skew.X;
double toY = toIdentity ? 0 : toValue.Data.Skew.Y;
result.Data.Skew.X = InterpolationUtilities.InterpolateScalars(fromX, toX, progress);
result.Data.Skew.Y = InterpolationUtilities.InterpolateScalars(fromY, toY, progress);
result.Bake();
break;
}
case OperationType.Matrix:
{
var fromMatrix = fromIdentity ? Matrix.Identity : fromValue.Matrix;
var toMatrix = toIdentity ? Matrix.Identity : toValue.Matrix;
if (!Matrix.TryDecomposeTransform(fromMatrix, out Matrix.Decomposed fromDecomposed) ||
!Matrix.TryDecomposeTransform(toMatrix, out Matrix.Decomposed toDecomposed))
{
return(false);
}
var interpolated =
InterpolationUtilities.InterpolateDecomposedTransforms(
ref fromDecomposed, ref toDecomposed,
progress);
result.Matrix = InterpolationUtilities.ComposeTransform(interpolated);
break;
}
case OperationType.Identity:
{
// Do nothing.
break;
}
}
return(true);
}