Re: plotyy

[John W. Eaton]

On 26-Nov-2007, David Bateman wrote:

| David Bateman wrote:
| > Here is an how plotyy might be implemented in a matlab compatible
| > manner.. To get the two plot axes aligned in gnuplot it forces the
| > margins in __go_draw_axes__ with the "set lmargin" and "set rmargin"
| > commands to gnuplot.
| > 
| > There is one issue with this that appears to be a gnuplot bug.. If I try
| > the example
| > 
| > 
| >           x = 0:0.1:2*pi;
| >           y1 = sin (x);
| >           y2 = exp(x - 1);
| >           ax = plotyy(x, y1, x - 1, y2, @plot, @semilogy);
| >           ylabel (ax(1), "Axis 1");
| >           ylabel (ax(2), "Axis 2");
| > 
| > then the text "Axis 1" appears twice, even though the xlabel command is
| > only sent to gnuplot once.. This might limit the usefulness of this for
| > publication plots until the issue is fixed in gnuplot, but plotyy is
| > still useful in any case.
| > 
| > D.
| 
| 
| Here is an updated version that addresses the doubled labels issue.
| Basically the problem was that gnuplot labels are persistent, and so are
| kept between plots. I therefore had to unset xlabel when I set x2label.
| There was also a bug in the {x|y|z}label changes I made.
| 
| Note that the manner in which this works is that if the axis property
| "position" is set, it is assumed we are dealing with a plotyy plot.
| Matlab sets a property which is called something like
| "ActivePositionType", though I haven't got matlab here at the moment and
| can't check. We can get the same effect just checking if "position" is
| empty and so I don't see the use of this matla specific flag.

I still think it would be better if we could somehow recognize that
there are multiple axes and use a single plot command, but as this
works and is a less invasive change, I applied it.

Thanks,

jwe