private void animScroll_Completed(object sender, EventArgs e)
{
Clock clock = (Clock)sender;
TaggedDoubleAnimation ani = (TaggedDoubleAnimation)clock.Timeline;
FrameworkElement element = ani.TargetElement;
tickerContainer.Children.Remove(element);
}
//displayNext will first retrieve the next TickerItemElement
//to be displayed, and then move the listPointer listPoint up by
//1. Then the function animItem is called on the retrieved element
//The retrieved item is added as a child of the tickers
//container.
//However, if the pointer variable listPoint exceeds the length
//of the list of items, it will then execute the same actions as
//in the Refresh function. The Refresh function itself cannot be
//called as the if statement will not pass the required parameters.
private void animItem(FrameworkElement e)
{
//animItem acts on a FrameWorkElement e
e.Measure(new Size(Double.PositiveInfinity,
Double.PositiveInfinity));
e.Arrange(new Rect(e.DesiredSize));
//The element is scaled and arranged in the standard method, into
//a rectangle of suitable size
startPos = tickerContainer.ActualWidth;
endPos = -1000;
//The start position is the far right of the ticker, and the end position is
//1000 pixels off of the far left of the ticker, so that items can be removed
//invisibly. This value is large since items with long descriptions, particularly
//at larger font sizes, may still have the description showing when they are
//removed otherwise
unitsPerSec = Convert.ToInt32((Math.Abs(startPos - endPos))
/ (animDuration.TotalSeconds));
nextFire = Convert.ToInt32((e.ActualWidth +
seperatorSize) / unitsPerSec);
//To calculate the appropriate time interval between a new item being
//scrolled along the screen, the amount of units per second is first
//defined as the full animation width, over the specified duration
//value in seconds. Then, using the width of the TickerItemElement
//and a seperator to prevent overlap, we calculate nextFire as this
//width plus the seperator size, divided by the units per second value
//This thusly defines the appropriate interval, which is recalculated
//each time to ensure that animation continues as expected. This
//nextFire variable specifies when the next item of news is to be scrolled
//along the screen, providing separation between newsitems so there is
//no overlap.
animTimer.Stop();
animTimer.Interval = new TimeSpan(0, 0, nextFire);
animTimer.Start();
//animTimer is stopped and restarted, with the new interval
//nextFire. As nextFire is calculated as a seconds value,
//this is placed in the seconds part of the new TimeSpan object.
animScroll = new TaggedDoubleAnimation();
animScroll.From = startPos;
animScroll.To = endPos;
animScroll.TargetElement = e;
animScroll.Duration = new Duration(animDuration);
animScroll.Completed += animScroll_Completed;
//animScroll is defined as a newTaggedDoubleAnimation, which animates from startPos
//to endPos, targeted on the TickerItemElement e. Its duration is formulated from
//the animDuration value, which is affected by the user set percentage modifier
//of the original speed value.
translate = new TranslateTransform();
e.RenderTransform = translate;
//A new TranslateTransform object is created, and this object is associated with the
//RenderTransform dependency property of the news item to be scrolled
translate.BeginAnimation(TranslateTransform.XProperty, animScroll, HandoffBehavior.Compose);
//Then, the animation is began, translating the X property of the TickerItemElement, the
//animScroll animation used to animate this property, and the handoff behavior is set to
//compose
}