/// <summary>
/// Gets a collection of items containing data for performing linear interpolation of managed key frames
/// when setting the content of the unmanaged Direct2D renderer's preview items cache.
/// </summary>
/// <param name="previewFrameNumber">The target frame number for creating interpolated unmanaged preview items.</param>
/// <param name="segmentModelsFilteredByFrameNumber">The source collection of frame number filtered segment models.</param>
/// <returns>A collection of data items for performing key frame linear interpolation.</returns>
protected IEnumerable <SegmentKeyFrameLerpDataItem> GetSegmentKeyFrameLerpDataForPreviewFrame(int previewFrameNumber, IEnumerable <SegmentModelBase> segmentModelsFilteredByFrameNumber)
{
foreach (SegmentModelBase segmentModel in segmentModelsFilteredByFrameNumber)
{
KeyFrameModelBase keyFrameAtOrBefore, keyFrameAfter = null;
double lerpAmount = 0d;
int keyFrameIndex = segmentModel.KeyFrames.BinarySearch(previewFrameNumber);
if (keyFrameIndex >= 0)
{
// Exact match for frame number found
keyFrameAtOrBefore = segmentModel.KeyFrames[keyFrameIndex];
}
else
{
// The index of the first key frame that has a frame number greater than or equal to previewFrameNumber
// or the value of segmentModel.KeyFrames.Count if no such key frame was found.
keyFrameIndex = ~keyFrameIndex;
keyFrameAtOrBefore = (keyFrameIndex > 0) ? segmentModel.KeyFrames[keyFrameIndex - 1] : segmentModel.KeyFrames[keyFrameIndex];
keyFrameAfter = (keyFrameIndex < segmentModel.KeyFrames.Count) ? segmentModel.KeyFrames[keyFrameIndex] : keyFrameAtOrBefore;
int frameRange = keyFrameAfter.FrameNumber - keyFrameAtOrBefore.FrameNumber;
if (frameRange > 0) // prevent double.NaN value as a result of division by zero
{
lerpAmount = (double)(previewFrameNumber - keyFrameAtOrBefore.FrameNumber) / frameRange;
}
}
yield return(new SegmentKeyFrameLerpDataItem(segmentModel.TrackNumber, keyFrameAtOrBefore, keyFrameAfter, lerpAmount));
}
}
/// <inheritdoc/>
public virtual SegmentViewModelBase CreateSplitSegmentModelViewModel(SegmentViewModelBase segmentViewModelToSplit, int frameNumberToSplitAt)
{
KeyFrameViewModelCollection splitKeyFrameViewModels = new KeyFrameViewModelCollection();
if (segmentViewModelToSplit.ActiveKeyFrame?.FrameNumber >= frameNumberToSplitAt)
{
segmentViewModelToSplit.ActiveKeyFrame = null;
}
int keyFrameIndex = segmentViewModelToSplit.KeyFrameViewModels.LowerBoundIndex(frameNumberToSplitAt);
if (keyFrameIndex < segmentViewModelToSplit.KeyFrameViewModels.Count)
{
KeyFrameViewModelBase keyFrameViewModel = segmentViewModelToSplit.KeyFrameViewModels[keyFrameIndex];
if (keyFrameViewModel.FrameNumber > frameNumberToSplitAt)
{
// Lerp new KeyFrameViewModel and add to splitKeyFrameViewModels
Debug.Assert(keyFrameIndex > 0);
keyFrameViewModel = segmentViewModelToSplit.KeyFrameViewModels[keyFrameIndex - 1].Lerp(frameNumberToSplitAt, keyFrameViewModel);
splitKeyFrameViewModels.Add(keyFrameViewModel);
}
// Loop from keyFrameIndex and move (via remove & add) KeyFrameViewModel(s) to splitKeyFrameViewModels
do
{
keyFrameViewModel = segmentViewModelToSplit.KeyFrameViewModels[keyFrameIndex];
segmentViewModelToSplit.KeyFrameViewModels.RemoveAt(keyFrameIndex);
segmentViewModelToSplit.Model.KeyFrames.RemoveAt(keyFrameIndex);
splitKeyFrameViewModels.Add(keyFrameViewModel);
} while (keyFrameIndex < segmentViewModelToSplit.KeyFrameViewModels.Count);
}
else
{
// Lerp new KeyFrameViewModel and add to splitKeyFrameViewModels
KeyFrameModelBase keyFrameModel = segmentViewModelToSplit.Model.KeyFrames.Last(kfm => kfm.FrameNumber < frameNumberToSplitAt).DeepCopy();
keyFrameModel.FrameNumber = frameNumberToSplitAt;
splitKeyFrameViewModels.Add(segmentViewModelToSplit.CreateKeyFrameViewModel(keyFrameModel));
}
int splitViewModelEndFrame = segmentViewModelToSplit.EndFrame;
segmentViewModelToSplit.EndFrame = frameNumberToSplitAt - 1;
return(CreateSegmentModelViewModel(segmentViewModelToSplit, segmentViewModelToSplit.TrackNumber,
frameNumberToSplitAt, splitViewModelEndFrame, segmentViewModelToSplit.Name,
splitKeyFrameViewModels));
}
/// <summary>
/// Gets a <see cref="KeyFrameModelCollection"/> containing the data models of key frame view models in a <see cref="KeyFrameViewModelCollection"/>,
/// optionally creating deep copies of the data models and offsetting the key frame numbers.
/// </summary>
/// <param name="keyFrameViewModels">The source <see cref="KeyFrameViewModelCollection"/>.</param>
/// <param name="createCopies">Whether to create deep copies of the data models. Defaults to false.</param>
/// <param name="frameOffset">The number of frames to offset the frame numbers of the data models by. Defaults to zero.</param>
/// <returns>
/// A <see cref="KeyFrameModelCollection"/> containing the data models of key frame view models in the <see cref="KeyFrameViewModelCollection"/>
/// which have been deep copied and/or frame offset if so specified.
/// </returns>
protected KeyFrameModelCollection GetKeyFrameModels(KeyFrameViewModelCollection keyFrameViewModels, bool createCopies = false, int frameOffset = 0)
{
KeyFrameModelCollection keyFrameModels = new KeyFrameModelCollection();
for (int i = 0; i < keyFrameViewModels.Count; i++)
{
KeyFrameModelBase keyFrameModel = createCopies ? keyFrameViewModels[i].Model.DeepCopy() : keyFrameViewModels[i].Model;
if (frameOffset != 0)
{
keyFrameModel.FrameNumber += frameOffset;
}
keyFrameModels.Add(keyFrameModel);
}
return(keyFrameModels);
}