Notification that a child changed.

  Notification that a child changed. This can effect
whether or not new offset calculations are needed.
This is called by a ChildState object that has
changed it's major span. This can therefore be
called by multiple threads.

  Fetch the allocation to use for a child view.

  Fetch the allocation to use for a child view.
This does not update the offsets in the ChildState
records.

  Fetch the allocation to use for a child view.

  Fetch the allocation to use for a child view.
This will update the offsets for all children
not yet updated before the given index.

  Fetches the child view index at the given point.

  Fetches the child view index at the given point.
This is called by the various View methods that
need to calculate which child to forward a message
to. This should be called by a block synchronized
on this object, and would typically be followed
with one or more calls to getChildAllocation that
should also be in the synchronized block.
Returns: the nearest child index
Parameters:
- x - the X coordinate >= 0
- y - the Y coordinate >= 0
- a - the allocation to the View

  Locate the view responsible for an offset into the box along the major axis.

  Locate the view responsible for an offset into the box
along the major axis. Make sure that offsets are set
on the ChildState objects up to the given target span
past the desired offset.
Returns: index of the view representing the given visual location (targetOffset), or -1 if no view represents that location

Paint the children that intersect the clip area.

  Copy the currently allocated shape into the Rectangle used to store the current allocation.

  Copy the currently allocated shape into the Rectangle
used to store the current allocation. This would be
a floating point rectangle in a Java2D-specific implmentation.

Move the location of the last offset calculation forward to the desired offset.

Move the location of the last offset calculation forward to the desired index.