Re: Compatible plotyy and colorbar (or Confusion about Position, OuterPosition and ActivePositionProperty)

[Ben Abbott]

On Oct 12, 2008, at 3:35 PM, David Bateman wrote:

> My colorbar/plotyy changes were recently added, and when  
> implementing it I had some issues with the treatment of the  
> position, outerposition and activepositionproperty properties of  
> axes objects.
>
> The behavior in matlab is described on the page
>
> http://www.mathworks.com/access/helpdesk/help/techdoc/creating_plots/f1-32495.html
>
> The actual size of the plot window is always determined by Position,  
> whereas the space allocated for the plot window and text is always  
> determined by OuterPosition. The ActivePositionProperty property is  
> only used to determine how the difference between Position and  
> OuterPosition are changed if the window is resized, so as gnuplot at  
> the moment gives no means to feedback this information (or rather  
> octave's interface to gnuplot), ActivePositionProperty is of no use.
>
> Now how Octave treated these values before my change is that
>
> * Octave's gnuplot interface uses OuterPosition in almost all cases  
> to define the position as gnuplot's origin/size paradigm bests fits  
> with use of OuterPosition. The exception is the plotyy function  
> where currently ActivePositionProperty is abused to force gnuplot to  
> have overlaying plots.
>
> * The graphics.cc (void axes::properties::sync_positions (void))  
> function maintains a constant relationship between Position and  
> OuterPosition. This is incorrect as adding a colorbar maintains the  
> OuterPosition and adjusts position.
>
> * The subplot function uses the OuterPosition property to recognize  
> subplots that are to an existing axis.
>
> So the correct implementation of the colorbar/plotyy function means  
> that we'll have to fix this to be more Matlab like. Basically what  
> this means is that
>
> * Octave should base its decision on the window placement in the  
> backends solely on the position property of the axis. This means  
> that the intelligence for the axis size needs to be placed in Octave  
> and not gnuplot.
>
> * The synchronization code between the position and outerposition  
> properties should be disabled till it is more intelligent and  
> capable of handling colorbars. For now this means that space for the  
> title, axis labels, legend, etc need to be hard coded into the  
> default position of the axes.
>
> I did that in the applied patch and fixed a couple of other issues  
> and now have a fully working plotyy and colorbar command. In  
> particular the mathworks example
>
> surf(peaks(30))
> colorbar('YTickLabel', 
> {'Freezing','Cold','Cool','Neutral','Warm','Hot','Burning','Nuclear'})
>
> works as expected when it didn't previously. However, the confusion  
> about the Position, OuterPosition and ActivePositionProperty remains  
> in the sense that the intelligence to calculate the size of the plot  
> to allow for the axis labels, etc isn't in Octave and so its  
> possible to make the plots label either fall outside the boundaries  
> of the plot. At some point, we'll need to add this intelligence to  
> Octave.
>
> Regards
> David

David,

I see a problem that appears to might be related to jwe's swtich to  
column vectors for handles.

For plotyy please try the demo below. It is the same as the one in  
plotyy with "subplot(221)" added as the first line.

%!demo
%! subplot(211)
%! x = 0:0.1:2*pi;
%! y1 = sin (x);
%! y2 = exp (x - 1);
%! ax = plotyy (x, y1, x - 1, y2, @plot, @semilogy);
%! xlabel ("X");
%! ylabel (ax(1), "Axis 1");
%! ylabel (ax(2), "Axis 2");

Using jwe's archive I get

error: get: invalid handle (= 3.42134e+180)
error: called from:
error:   /Users/bpabbott/Development/mercurial/octave-3.1.51/scripts/ 
plot/__go_draw_axes__.m at line 1314, column 9
error:   /Users/bpabbott/Development/mercurial/octave-3.1.51/scripts/ 
plot/__go_draw_axes__.m at line 271, column 8
error:   /Users/bpabbott/Development/mercurial/octave-3.1.51/scripts/ 
plot/__go_draw_figure__.m at line 59, column 8
error:   /Users/bpabbott/Development/mercurial/octave-3.1.51/scripts/ 
plot/gnuplot_drawnow.m at line 68, column 5

The problems do not end there

octave:6> clf
error: delete: invalid graphics object (= -16.9272)
error: called from:
error:   /Users/bpabbott/Development/mercurial/octave-3.1.51/scripts/ 
miscellaneous/delete.m at line 40, column 1
error:   /Users/bpabbott/Development/mercurial/octave-3.1.51/scripts/ 
plot/clf.m at line 37, column 9

Notice this second error references a different handle.

I also notice that the xlabe("X") command changes the orientation of  
the children for the axis from a column vector to a row vector. For  
the row vector the second element is invalid.

btw, my response to this is rather quick because I was coincidentally  
working on plotyy as well. My effort was to get it to work with subplot.

Ben