/// <summary>
/// Executes an operation on an already existing SiblingLayoutInfo or create it before executing.
/// </summary>
private T ExecuteOnSiblingLayoutInfoIfAvailable <T>(IFrameworkElement child, Dictionary <IFrameworkElement, SiblingLayoutInfo> siblingLayoutInfos, Func <SiblingLayoutInfo, T> operation)
{
if (!siblingLayoutInfos.ContainsKey(child))
{
siblingLayoutInfos[child] = new SiblingLayoutInfo();
}
return(operation(siblingLayoutInfos[child]));
}
/// <summary>
/// Get the area (including location) of a child based on the measured size and the layout information of other children in order
/// </summary>
/// <param name="availableArea">The child's available area</param>
/// <param name="childSize">The measured child size</param>
/// <param name="siblingLayoutInfo">The information about the previously laid out children</param>
private Rect ComputeChildArea(Rect availableArea, Size childSize, SiblingLayoutInfo siblingLayoutInfo)
{
var location = availableArea.Location;
if (siblingLayoutInfo.IsRightBound && !siblingLayoutInfo.IsLeftBound && !double.IsPositiveInfinity(availableArea.Right))
{
location.X = availableArea.Right - childSize.Width;
}
else if (!double.IsNaN(siblingLayoutInfo.Center.X))
{
location.X = siblingLayoutInfo.Center.X - (childSize.Width / 2);
}
if (siblingLayoutInfo.IsBottomBound && !siblingLayoutInfo.IsTopBound && !double.IsPositiveInfinity(availableArea.Bottom))
{
location.Y = availableArea.Bottom - childSize.Height;
}
else if (!double.IsNaN(siblingLayoutInfo.Center.Y))
{
location.Y = siblingLayoutInfo.Center.Y - (childSize.Height / 2);
}
return(new Rect(location, childSize));
}
