"Restore View" limits come from... where?

I'm having some difficulty with a plot in Matlab 2018b. After plotting the data, I select the "Zoom In" option from the axes menu on the top-right, and zoom in and out to inspect the data. I later select "Restore View" from the context menu available when using "Zoom In", expecting it to go back to what it was after I plotted the data. However, I end up with a blank white axes with XLim [0 1]. (Legitimate X limits would be along the lines of [7.3705e+05 7.3740e+05].) Manually setting the X limits reveals that my data plots are still there, but well out of view.

My question is: Where is Matlab getting the limits that should be used when performing "Restore View"?

If needed, here's some more detailed information:

I am using a stack of two axes, directly overlaid on top of each other, inside of a graphics panel. The two axes are linked on the X-axis ("linkaxes([a,b],'x');"). The "upper" axes are set to have no background color, and "PickableParts" has been set to none.

[Walter Roberson]

It has been a while since I looked at that code. I have a half memory of noting that the portion dealing with restoring from linked axes was a bit messy and looked like it would be prone to error.

I seem to recall that when the plot is rendered in an axes that has a modal behavior manager active on it, that the XLim and YLim properties are stored as UserData (might have been AppData), and that Restore View pulls those values out... at least in the simple non-linked case.

[Sean Mahnken]

Thanks, Walter. That is EXACTLY the answer I was looking for.

Recognizing that I may just have to fiddle with it, I'll ask a follow-on question anyway. The AppData structure has two candidates. There is an array called "zoom_zoomOrigAxesLimits", and there is a substructure "matlab_graphics_resetplotview" with an XLim member. Both show [0 1] and would explain why I'm seeing what I'm seeing. Do you happen to know which of the two is referenced by the "Restore View" function(s)?

Answer 1

[Walter Roberson]

Look in zoom.m function getbounds(), about line 1074. It is axes appdata zoom_zomOrigAxesLimits that it pulls out to make sure you do not zoom out too far.

With you having two axes, then I would worry about the expected axes being the active axes.

[Sean Mahnken]

Perfect. That's what I needed. I was using axes() to switch back and forth between the two, which was resulting in the problems. If I just set the axes to the main plot, and leave it, the problem goes away.

Thanks for your help!

[Andrew Landau]

Related question-

I'm designing a gui with appdesigner, and want to be able to set the default xlim. It appears that you can set the default xlim for a freestanding axes, but not for an axes within an appdesigner app.

A MWE is as follows:

x = 1:512;  
y = rand(1,512); 
figure; 
plot(x,y); 
xlim([1 512]);

If you zoom in then hit the "Restore View" home button, it will go back to xlim([1 512]), even though it doesn't default to that before it is set.

A MWE for the appdesigner:

To make this work you need a file with the classdef code that's larger, then run the following two lines:

test = testAxesLimit; % Create app
ax = returnAx(test); % Return axes 

If you zoom in then hit restore view, it will go back to ~xlim([1 550])...

It's a simple issue but I'd love to fix it if possible!

Here's the classdef:

classdef testAxesLimit < matlab.apps.AppBase

    % Properties that correspond to app components
    properties (Access = public)
        UIFigure  matlab.ui.Figure
        testAx    matlab.ui.control.UIAxes
    end

    
    methods (Access = public)
        
        function ax = returnAx(app)
            ax = app.testAx;
        end
    end
    

    % Callbacks that handle component events
    methods (Access = private)

        % Code that executes after component creation
        function startupFcn(app)
            x = 1:512;
            y = rand(1,512);
            plot(app.testAx,x,y);
            xlim(app.testAx,[1 512]);
        end
    end

    % Component initialization
    methods (Access = private)

        % Create UIFigure and components
        function createComponents(app)

            % Create UIFigure and hide until all components are created
            app.UIFigure = uifigure('Visible', 'off');
            app.UIFigure.Position = [100 100 640 480];
            app.UIFigure.Name = 'UI Figure';

            % Create testAx
            app.testAx = uiaxes(app.UIFigure);
            title(app.testAx, 'Title')
            xlabel(app.testAx, 'X')
            ylabel(app.testAx, 'Y')
            app.testAx.Position = [48 60 536 356];

            % Show the figure after all components are created
            app.UIFigure.Visible = 'on';
        end
    end

    % App creation and deletion
    methods (Access = public)

        % Construct app
        function app = testAxesLimit

            % Create UIFigure and components
            createComponents(app)

            % Register the app with App Designer
            registerApp(app, app.UIFigure)

            % Execute the startup function
            runStartupFcn(app, @startupFcn)

            if nargout == 0
                clear app
            end
        end

        % Code that executes before app deletion
        function delete(app)

            % Delete UIFigure when app is deleted
            delete(app.UIFigure)
        end
    end
end

[Walter Roberson]

Sorry, I have only looked at the very surface of how appdesigner works.

Answer 2

[breathi]

Since this thread is in the top search results for linkaxes as well, here is a related article for linkaxes from MathWorks: https://www.mathworks.com/matlabcentral/answers/426098-zoom-auto-doesn-t-work-with-linkaxes-when-data-is-replaced

So for linkaxes, the easiest solution is to restore the auto mode for Lim:

% ax is an Axes array

% link x axes of all plots
linkaxes(ax,'x');

% reset XLimMode back to auto to properly "Restore View" when data is
% exchanged
[ax.XLimMode] = deal('auto');

In other cases, Walter is right. Here some more information.

From my info, "Restore View" finally triggers

resetplotview

which is an internal function. A more common function to restore the view is

zoom out;

For R2021a, the appdata change can be seen in localResetPlotView():

edit(fullfile(matlabroot, 'toolbox', 'matlab', 'graphics', 'resetplotview.m'))

So basically, the standard view of an axes can be found with

getappdata(ax)

And as Walter suggested, look for "zoom_zoomOrigAxesLimits". If it is not set, the axes view has not yet been modified by zoom/pan. Changing the limit property also doesn't set a "Restore View" point.

To manually set the "Home" zoom of an axes (https://www.mathworks.com/matlabcentral/answers/345743-how-can-i-change-the-default-original-view-that-a-figure-resets-to-when-i-double-click-inside-the-fi), use

zoom reset;

To delete the "Home" zoom of an axes (https://www.mathworks.com/matlabcentral/answers/23318-reset-to-original-view-with-zoom), use

resetplotview(ax,'InitializeCurrentView');
% or possibly remove the zoom data fields:
rmappdata(ax, 'zoom_zoomOrigAxesLimits');
rmappdata(ax, 'matlab_graphics_resetplotview');