How do I make both yyaxis axes zoom together?

When I plot two figures using "yyaxis" and use the interactive zoom, only the right (active) axis zooms. The other one does not get updated. How can I fix this?

Answer 1

[MathWorks Support Team]

This behavior is in accordance with the "yyaxis" function documentation (See under "Axes Properties" in the "More About" section of the link below)

https://www.mathworks.com/help/matlab/ref/yyaxis.html

However, you can achieve the desired behavior by following these steps:

1. Plot your data using "yyaxis" as normal

2. Create a callback function that, before the zoom happens, saves the old axis limits.

3. Create a callback function that, after the zoom happens, edits the axis values for the (previously unaffected) left axis.

In the attached files, file "saveAxisStatus.m" defines the pre-zoom callback behavior, and "zoomSecondAxis.m" defines the post-zoom callback behavior. The file "Example.m" demonstrates how to use these two functions.

 

Answer 2

[Andres]

I have uploaded a solution (yyzoom) to the File Exchange,

https://www.mathworks.com/matlabcentral/fileexchange/102945-yyaxis-tools

that stores the base values for the axes limits relation inside the callback function of a listener to the YLim property of the yyaxis chart axes. I've had the opportunity to test it with R2021a/b up to now.

Answer 3

[Julian Hapke]

Here's a function that does not rely on an activated zoom tool and also works for panning

function yysync(ax)

%YYSYNC links left and right yyaxis, so they pan and zoom synchronously

%

% unfortunately the PostSet event is also triggered when ylim() is called

% so if you want to set axis limits independently, you have to to so before

% calling yysync

%

% Syntax:

% yysync(ax)

%

% Inputs:

% ax:

% the axes whose yyaxis shall be linked

% graphics handle

% required

%

% Outputs:

% -

%

% Examples:

% -

%

% See also: yyaxis, ylim

%

rulers = ax.YAxis;

if numel(rulers) == 1

% no second y axis

return

end

factor = diff(rulers(2).Limits) / diff(rulers(1).Limits);

offset = rulers(2).Limits(1) - factor * rulers(1).Limits(1);

function setOtherLimits(~, event)

obj = event.AffectedObject;

if obj.YAxisLocation == "right"

obj.YAxis(1).Limits = (obj.YLim - offset) / factor;

else

obj.YAxis(2).Limits = factor .* obj.YLim + offset;

end

end

addlistener(ax, 'YLim', 'PostSet', @setOtherLimits);

end