| Author: | Tuomas J. Lukka |
|---|---|
| Last-Modified: | 2003-03-31 |
| Revision: | 1.1 |
| Status: | Accepted |
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.
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.
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);