Re: Stem update, rough guess.

[John W. Eaton]

On  9-Apr-2007, Daniel J Sebald wrote:

| The baseline that is a child of the axis seems like what I had in mind, i.e., 
| zero axis line, i.e., something very general that applies to not only stem 
| plots.

Yes, but that child is just a simple line.  There seems to be nothing
special about it that indicates that it is a "baseline".

| Does stem allow a baseline other than at y=0?

Yes,

  h = stem (-10:10);
  set (h, 'basevalue', 3);

works.

| If so, that would explain the extra baseline handle.

| I'd say, leave out the one that is passed back as a 
| handle and implement the one that is a child of the axis using the gnuplot 
| command.

Yes, I think this would be OK, but again, the line that is a child of
the axes object does not appear to be special.

Again, the X data for both the child of the axes object and the
baseline object that is a child of the stemseries object changes when
the axis limits are changed.  So it is not sufficient to have a
special property that is recognized and translated into a special
gnuplot command.  Instead, the data for these objects should be
modified when the limits change and then drawing the lines will
generate the proper plot.  But since there is probably no way to do
this completely right until we have group objects, I think it would be
OK to have the baseline be a child of the axes object and not worry
about resizing it automatically.  I think that is a small bug compared
to not having it as a line object.

Finally, all this detail is already much more than I want to know
about implementing stem plots with the graphics objects, so someone
else will have to dive in to discover any further details of how it is
supposed to work.

jwe