/// <summary>
/// Begins dragging the given <paramref name="draggable"/> so long as the <see cref="CurrentDraggable"/> is null. Uses the given <paramref name="offset"/> when keeping the draggable pinned to the mouse.
/// Calls <see cref="IDraggable.OnDragBegin(Point)"/> with the given <paramref name="offset"/> and sets the <see cref="CurrentDraggable"/> to its return value.
/// </summary>
/// <param name="draggable"></param>
/// <param name="offset"></param>
public bool BeginDragging(IDraggable draggable, Point offset)
{
// Return false if the state is invalid.
if (draggable == null || CurrentDraggable != null)
{
return(false);
}
// Begin dragging the given draggable.
IDraggable newDraggable = draggable.OnDragBegin(offset, out Point newOffset);
// If the given draggable returned a null value, return false.
if (newDraggable == null)
{
return(false);
}
// Set the current draggable and offset.
CurrentDraggable = newDraggable;
DraggableOffset = newOffset;
DraggableOrigin = CurrentDraggable.Bounds.AbsoluteTotalPosition;
// Return true as the dragging was begun.
return(true);
}