/// <summary>
/// When overridden in a derived class, measures the size in layout required for child elements and determines a size for the <see cref="T:System.Windows.FrameworkElement" />-derived class.
/// </summary>
/// <param name="availableSize">The available size that this element can give to child elements. Infinity can be specified as a value to indicate that the element will size to whatever content is available.</param>
/// <returns>
/// The size that this element determines it needs during layout, based on its calculations of child element sizes.
/// </returns>
protected override Size MeasureOverride(Size availableSize)
{
var worldLayer = World;
var viewportLayer = this;
if (worldLayer == null)
return new Size();
foreach (UIElement child in InternalChildren)
{
if (child == null)
continue;
var left = GetLeft(child);
var top = GetTop(child);
var right = GetRight(child);
var bottom = GetBottom(child);
var rect = new Rect(0, 0, Math.Abs(right - left), Math.Abs(bottom - top));
var constraint = rect.Translate(worldLayer, viewportLayer).Size;
if (double.IsNaN(constraint.Width))
constraint.Width = double.PositiveInfinity;
if (double.IsNaN(constraint.Height))
constraint.Height = double.PositiveInfinity;
child.Measure(constraint);
}
return new Size();
}
