datacursormode isn't working on a specific UIAxes for Matlab R2023a

I have MATLAB R2023a. I have a matlab app with different UIAxes. I would like to assign different custom data cursor behavior for each UIAxes. However, when I try to use:

dcm1 = datacursormode(app.UIAxes1, 'on');
set(dcm1, 'UpdateFcn', @(~, event_obj) customDataCursorForUIAxes1(app, event_obj));

I get matlab error saying: Invalid figure handle. I don't understand what's the reason behind that specifically that it's supposed to be a valid new feature:

"datacursormode(ax,option) sets the data cursor mode for the specified axes. For example, to enable data cursor mode for the axes ax, use datacursormode(ax,'on'). Use this syntax with apps created in App Designer and using the uifigure function. (since R2023a)"

[Harald]

Hi Omnia,

Which line is throwing the error?

If possible, please attach a small reproducible example that shows the problem.

Best wishes,

Harald

[Omnia]

Hi Harald,

This line that is causing the error:

dcm1 = datacursormode(app.UIAxes1, 'on');

I have various UIAxes in my app and I would like to assign individual custom data cursor to some of the UIAxes I have and leave some without any custom data cursor.

methods (Access = private)
        % ... rest of the code
    
        function output_txt = customDataCursorForUIAxes1(~, event_obj, objInfo)
            pos = event_obj.Position;
            output_txt = {['X: ' num2str(pos(1))], ['Y: ' num2str(pos(2))]};
        end
    
        function output_txt = customDataCursorForUIAxes2(~, event_obj, objInfo)
            pos = event_obj.Position;
            seriesName = get(event_obj.Target, 'DisplayName');
            if isnumeric(objInfo)
                objLabel = ['#' num2str(objInfo)];
            else
                objLabel = ['#' seriesName];
            end
            output_txt = {objLabel, ['X: ' num2str(pos(1))], ['Y: ' num2str(pos(2))]};
        end
    
        % ... custom data cursor function for UIAxes 3, 4, 5, .... etc
end


 % Button pushed function: CalculateButton
        function CalculateButtonPushed(app, event)
            % ... rest of the code

            % ... plotting of app.UIAxes1
            dcm1 = datacursormode(app.UIAxes1, 'on');
            set(dcm1, 'UpdateFcn', @(~, event_obj) customDataCursorForUIAxes1(app, event_obj));

            % ... plotting of app.UIAxes2
            dcm2 = datacursormode(app.UIAxes2, 'on');
            set(dcm2, 'UpdateFcn', @(~, event_obj) customDataCursorForUIAxes2(app, event_obj));

            % ... plotting of app.UIAxes3, app.UIAxes4, 5, ... etc and their corresponding Update Function
        end

Kind regards,

Omnia

[Harald]

Hi Omnia,

if possible, please attach the .mlapp file. This will make it much easier to reproduce the problem.

A simplified example certainly is enough, but it should still be reproducible for us.

Thanks and best wishes,

Harald

[Wenzhao]

Same problem. I have installed matlab2023a. According to https://www.mathworks.com/help/matlab/ref/matlab.graphics.shape.internal.datacursormanager.html

datacursormode(axe, 'on') is supposed to work in matlab App.

However my datacursormode.m in the path 'C:\Program Files\MATLAB\R2023a\toolbox\matlab\graphics' is still 2022version.

DATACURSORMODE only works on figure handle not on axe handle yet.

function retval = datacursormode(varargin)
%DATACURSORMODE Interactively create data cursors on plot
%   DATACURSORMODE ON turns on cursor mode.
%   DATACURSORMODE OFF turns off cursor mode
%   DATACURSORMODE by itself toggles the state.
%   DATACURSORMODE(FIG,...) works on specified figure handle.
%
%   H = DATACURSORMODE(FIG)
%        Returns the figure's data cursor mode object for
%        customization. The following properties can be
%        modified using set/get:
%
%        Figure <handle>
%        Specifies associated figure handle. This property
%        supports GET only.
%
%        Enable  'on'|'off'
%        Specifies whether this figure mode is currently
%        enabled on the figure.
%
%        SnapToDataVertex 'on'|'off'
%        Specified whether data cursors snap to nearest data
%        value or appear at mouse position.
%
%        DisplayStyle 'datatip' | 'window'
%        'datatip' displays cursor information as a text box
%        and marker and 'window' displays cursor information
%        in a floating window within the figure.

...
    

if nargin==0
    fig = gcf;
    action = 'toggle';
elseif nargin==1
    arg1 = varargin{1};
    if ischar(arg1) || isstring(arg1)
        if nargout > 0
            error(message('MATLAB:datacursormode:NoOutputOnEnableDisable')); 
        end
        % Check for valid action types else throw an error
        actionTypes = {'on','off','toggle','ison','retval','none'};
        if isempty(find(strcmpi(arg1,actionTypes), 1))
            error(message('MATLAB:datacursormode:UnrecognizedInput'));
        else
            action = arg1;
            fig = gcf;
        end        
    elseif ishghandle(arg1,'figure')
        fig = arg1;
        if nargout==1
            action = 'retval';
        else
            action = 'toggle';
        end
    end
    
elseif nargin==2
    fig = varargin{1};
    action = varargin{2}; 
    if ~strcmpi(action,'-nocontextmenu') && nargout > 0
        error(message('MATLAB:datacursormode:InvalidInputForOutArg'));        
    end 
else
    error(message('MATLAB:datacursormode:maxrhs'));
end
fig = handle(fig);
if isempty(fig) || ~ishghandle(fig,'figure')
    error(message('MATLAB:datacursormode:InvalidFigureHandle'))
end

[Harald]

Hi Wenzhao,

the behavior of a function can also change if a function that it calls changes, so the timestamp of one function does not necessarily mean anything.

Same as to Omnia: if you can supply a fully reproducible example, this will be helpful.

Best wishes,

Harald

[Walter Roberson]

@Wenzhao

datacursormode() only works on uiaxes(), not on axes()

[Wenzhao]

Exactly. I just give it as an example.

When I was developing an APP, it would be like this " datacursormode(app.UIaxes_xxx, 'on')". But it doesnt work.

That is why I check datacursormode.m file and HELP.

As I emphasized ("DATACURSORMODE only works on figure handle not on axe handle yet."), the datacursormode.m is not support what HELP tell.

[Walter Roberson]

The comments have not been updated to reflect accepting an axes. The code for handling an axes starts at roughly line 117

webAxesInputArgument = (nargin > 0) && matlab.graphics.interaction.internal.isWebAxes(varargin{1});

Answer 1

[Walter Roberson]

At the time you make the call

dcm1 = datacursormode(app.UIAxes1, 'on');

app.UIAxes1 is not a valid Axes object that is parented by a uifigure .

For example it might be parented by a traditional figure, or it might have been deleted.

(Or at least toolbox/matlab/graphics/+matlab/+graphics/+interaction/+internal/isWebAxes.p cannot detect that it is an Axes parented by a uifigure. That is a .p file so we cannot check it for potential bugs involving container objects.)