Camera timer animation on UWP - animation

Question

I am developing an UWP application, and one of my page is actually for user to take photo of them. In the page, I have timers for user to select before they take picture.
However, I wish to have a timer shown, counting down in the camera screen, so that the user know how much time is left for them to prepare, before the picture is taken.
Any idea on how I can do that? Thank you!
Just in case it is needed, here is my codes for the timers and the take picture buttons:
private async void PhotoButton_Click(object sender, RoutedEventArgs e)
{
//If preview is not running, no preview frames can be acquired
if (!_isPreviewing) return;
await Task.Delay(TimeSpan.FromSeconds(_seconds));
await TakePhotoAsync();
await GetPreviewFrameAsSoftwareBitmapAsync();
PreviewFrameBackground.Visibility = Visibility.Visible;
}
private void Timer_3sec_Click(object sender, RoutedEventArgs e)
{
Timer_5sec.Opacity = 0.2;
Timer_7sec.Opacity = 0.2;
Timer_3sec.Opacity = 1.0;
_seconds = 3;
}
private void Timer_5sec_Click(object sender, RoutedEventArgs e)
{
Timer_3sec.Opacity = 0.2;
Timer_7sec.Opacity = 0.2;
Timer_5sec.Opacity = 1.0;
_seconds = 5;
}
private void Timer_7sec_Click(object sender, RoutedEventArgs e)
{
Timer_3sec.Opacity = 0.2;
Timer_5sec.Opacity = 0.2;
Timer_7sec.Opacity = 1.0;
_seconds = 7;
}

Answer 1

You can use a DispatcherTimer to solve your problem.
Here a little code sample how you can do that (The sample dont show how to take the capture or to show the remaining seconds, just to calculate them!)
Class-Parameters:
private int _startTime;
private DispatcherTimer _timer = new DispatcherTimer();
Methods:
private void StartTimer()
{
_timer.Interval = TimeSpan.FromMilliseconds(500);
_timer.Tick += Timer_Tick;
_startTime = Environment.TickCount;
_timer.Start();
}
private void Timer_Tick(object sender, object e)
{
var remainingSeconds = _seconds - TimeSpan.FromMilliseconds(Environment.TickCount - _startTime).Seconds;
if(remainingSeconds <= 0)
{
_timer.Stop();
_timer.Tick -= Timer_Tick;
timerText.Text = "0 Seconds";
//Capture Image
} else
{
timerText.Text = "" + remainingSeconds + " Seconds";
}
}
You need to call the StartTimer-Method in you Click-Methods, after setting the _seconds.