Question

I have an animation inside a Behavior, but it is not running fluid.

Here is my animation code:

DoubleAnimationUsingKeyFrames animation = new DoubleAnimationUsingKeyFrames();

animation.SetValue(Storyboard.TargetPropertyProperty, new PropertyPath("(0).(1)", UIElement.RenderTransformProperty, RotateTransform.AngleProperty));

int keyFrameCount = 16;
double timeOffsetInSeconds = 0.1;
int targetValue = 12;

double totalAnimationLength = keyFrameCount * timeOffsetInSeconds;
double repeatInterval = RepeatInterval;
bool isShaking = IsShaking;

// Can't be less than zero and pointless to be less than total length
if (repeatInterval < totalAnimationLength)
    repeatInterval = totalAnimationLength;

animation.Duration = new Duration(TimeSpan.FromSeconds(repeatInterval));

for (int i = 0; i < keyFrameCount; i++)
{
    animation.KeyFrames.Add(new LinearDoubleKeyFrame(i % 2 == 0 ? targetValue : -targetValue, KeyTime.FromTimeSpan(TimeSpan.FromSeconds(i * timeOffsetInSeconds))));
}

animation.KeyFrames.Add(new LinearDoubleKeyFrame(0, KeyTime.FromTimeSpan(TimeSpan.FromSeconds(totalAnimationLength))));

But, if i choose

int keyFrameCount = 360;

and

for (int i = 0; i < keyFrameCount; i++)
{
    animation.KeyFrames.Add(new LinearDoubleKeyFrame(i, keyTime.FromTimeSpan(TimeSpan.FromSeconds(i * timeOffsetInSeconds))));
}

it will rotate a very smooth circle.

How can I achieve to let the animation go from 0 to 30 degrees, back to -30 degrees,
and then back to 0 (to let it dither around a bit) AND have it look fluent.

After some tries, I see that (normal) back and forth will not work here,
it behaves totally uncontrolled!

Answer 1

I’m not really sure why you’re doing so many keyframes yourself, but in order to do

How can I achieve to let the animation go from 0 to 30 degrees, back to -30 degrees, and then back to 0 (to let it dither around a bit) AND have it look fluent.

You could change the animation to something like

DoubleAnimationUsingKeyFrames animation = new DoubleAnimationUsingKeyFrames();

animation.SetValue(Storyboard.TargetPropertyProperty, new PropertyPath("(0).(1)", UIElement.RenderTransformProperty, RotateTransform.AngleProperty));

var totalAnimationLength = 1600; // Milliseconds

double repeatInterval = 1600;// Milliseconds

if (repeatInterval < totalAnimationLength) repeatInterval = totalAnimationLength; // Can't be less than zero and pointless to be less than total length 

animation.Duration = new Duration(TimeSpan.FromMilliseconds(repeatInterval));
animation.RepeatBehavior = RepeatBehavior.Forever; // assuming this was intended from having a repeat interval?

animation.KeyFrames.Add(new LinearDoubleKeyFrame(30, KeyTime.FromTimeSpan(TimeSpan.FromMilliseconds(totalAnimationLength * 0.25))));
animation.KeyFrames.Add(new LinearDoubleKeyFrame(-30, KeyTime.FromTimeSpan(TimeSpan.FromMilliseconds(totalAnimationLength * 0.75))));
animation.KeyFrames.Add(new LinearDoubleKeyFrame(0, KeyTime.FromTimeSpan(TimeSpan.FromMilliseconds(totalAnimationLength))));