Zooming separately on both data sets while using plotyy

Is there anyway that I can selectively zoom on the two data sets when I am using plotyy?

In other words I want to re-scale and position the the data separately after plotting and can't seem to make this happen as of now. I came across the following but, I wasn't sure how I could convert it into a function for automatic plotting using plotyy:

http://stackoverflow.com/questions/16347784/matlab-pan-a-plot-independently-of-other-plots-in-the-same-axes

[dpb]

You've already got two independent axes w/ plotyy -- the only real piece it would seem you'd need to add would be to hide the non-selected of the two axes when selected the other -- as is by default they both are visible and simply overlay so it visually looks as though there's only one.

[Donald John]

Thanks for this comment, how would I go about hiding each axis so that I could seperately zoom in that case?

Can I do this in the Figure window with the plot tools, or would I have to write this in the code?

Answer 1

[Jan]

The sense of PLOTYY is the joining of the data-sets. When you want to handle them separately, do not use PLOTYY, but create the two axes manually:

AxesH(1) = axes('NextPlot', 'add', ...
              'XAxisLocation', 'bottom', ...
              'YAxisLocation', 'left');
AxesH(2) = axes('NextPlot', 'add', ...
              'XAxisLocation', 'top', ...
              'YAxisLocation', 'right', ...
              'Color', 'none');

plot(1:10, rand(1:10), 'Color', [1,0,0], 'Parent', AxesH(1), ...
     'ButtonDownFcn', {@LineSelect, AxesH});
plot(1:10, rand(1:10), 'Color', [0,0,1], 'Parent', AxesH(2), ...
     'ButtonDownFcn', {@LineSelect, AxesH});

function LineSelect(ObjectH, EventData, AxesH)
SelectedAxes = get(ObjectH, 'Parent');
Fig          = ancestor(SelectedAxesH, 'Figure');
set(Fig, 'CurrentObject', SelectedAxes);
% Now an idea is missing

Finally the code can activate an axes, but I'm not sure if the zooming is restricted to this axes. So this is only a rough idea yet.

[Donald John]

Thanks for this. It looks good but zooming does seem to be restricted to the active axis. However the data have a coincident x-axis for which I am using dates. This is the reason I am using plotyy. So all I really want to do is zoom on the separate y-axis, while ensuring that the x-axis remains coincident.

I guess what I need is an option in the figure to select one of the y-axis and zoom on that, then to select the other axis and separately zoom on that axis.

[Jan]

You could link the X-Axes by LINKAXES.

Answer 2

[Sean de Wolski]

doc zoom

You can use the function setAllowedAxesZoom to set false for the axes you don't want zooming. Now, why doesn't this work out of the box? When you call plotyy a bunch of hidden listeners are set up to keep the axes aligned, i.e. when one zooms, the other does too.

These listeners are not initiated when generating code for the figure and then setting axes zoom allowed to false. Here's an example with code and instructions:

hFig = figure;
plotyy(1:10,4:13,2:11,1:10:100);

• Now click File Menu -> Generate Code
• Save the file as createfigure.m

The signature should look like this:

createfigure(X1, Y1, X2, Y2);

Change the signature to the following

ax = createfigure(X1, Y1, X2, Y2);

And change the last line of the function to

ax = [axes1 axes2];

Now you are passing back the handles to the axes. Get the zoom handle for the figure and turn it off for the second axes. Here's the full example:

hFig = figure;
ax = createfigure(1:10,4:13,2:11,1:10:100);
h = zoom(hFig);
setAllowAxesZoom(h,ax(2),false);

Enjoy zooming!

[Donald John]

Sorry if this is a silly question but do I need to create a separate function to get this to work? Can this all be done in the editor window?

[Sean de Wolski]

Well you copy the contents out of the function that is autogenerated (this will look similar to Jan's code below) and then use that inlined in your script. That is your call, I would keep the createfigure function as its own, that way it can be used again in another script if necessary.

[Donald John]

Sorry again, but I am using MATLAB R2012b and I can't seem to find the Generate Code option in the file ribbon menu. Am I looking in the wrong place?

[Sean de Wolski]

Look in the figure file menu at the top left corner of the figure.