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[Gzz] PEG vobcoorder_parents--tjl
From: |
Tuomas Lukka |
Subject: |
[Gzz] PEG vobcoorder_parents--tjl |
Date: |
Mon, 28 Oct 2002 17:31:22 +0200 |
User-agent: |
Mutt/1.4i |
Submitting this as well...
=============================================================
PEG vobcoorder_parents--tjl:
=============================================================
:Author: Tuomas J. Lukka
:Date: $Date: 2002/10/28 15:28:18 $
:Revision: $Revision: 1.1 $
:Status: Incomplete
For the mouse click stuff to work properly with the Box API, we need
to be able to query parents etc. That's a nice piece of functionality
anyway.
The connection to the Box API is as follows: the mouse clicks are determined
inside
the unit square (see PEG 1021). For boxes, the unit square is a separate
coordinate
system from the box itself and will always have the same key
(Box.UNITCOORDSYSKEY).
Because of this, getting the parent is necessary when interpreting the mouse
click.
Issues
------
- What should getParent(0) return?
RESOLVED: It should return -1.
The reasonable alternatives would be 0 and -1, and 0
would easily lead to infinite loops. With -1, it's easy to go backwards
until ``cs<0``.
Changes
-------
Add into VobCoorder::
/** Get the primary parent of the given coordinate system.
* getParent(0) will return -1.
* Always equal to getParents(cs)[0]
*/
abstract public int getParent(int cs);
/** Return an array with all the parent and determining coordinate
* systems of the given coordinate system. For instance, for a coordsys
* created with GLVobCoorder.nadirOrigin, this should be an array of length
two.
*/
abstract public int[] getParents(int cs);
- [Gzz] PEG vobcoorder_parents--tjl,
Tuomas Lukka <=