https://learn.microsoft.com/ru-ru/dotnet/api/system.windows.media.animation.animatable.getanimationbasevalue?view=netframework-4.8.1&viewFallbackFrom=windowsdesktop-9.0
Animatable.GetAnimationBaseValue(DependencyProperty) Method (System.Windows.Media.Animation) |...
Returns the non-animated value of the specified DependencyProperty.
windows mediaanimatablemethodsystemanimation