How do you set a default datatip callback function?

I'm trying to add callback code to a scatterplot that activates when the use clicks on a data point. To do this, I want to assign the callback to the creation function of a datatip. The datatip documentation says that datatips have a creation callback. I want to set a default value for this callback function so it executes whenever any new datatip is created. However, when I try to set this default value as described here, I get an error that says "datatip is an invalid class name".

My primary question is how do I assign a callback function that is executed whenever any datatip is created. A more general question is, what's the best way to set code to execute whenever the user clicks on an existing data point in a figure? Lines are objects that have properties, but the data points themselves are not.

Code to recreate the error:

x=1:10;

y=1:10;

figure

hold on

scatter(x,y,'filled');

hold off

set(groot,'defaultDataTipCreateFcn',@tipcreate);

function tipcreate(~,~)

disp('Hello World!');

end

Answer 1

[Adam Danz]

It doesn't appear that there is a factory CreateFcn for Data Tips and its default value is an empty character array ('').

The list below shows all factory options for CreateFcn functions.

You could, of course, define a function in an m-file, add the file to the path in startup.m, and assign the function to all datatips. But I realize that isn't as ideal as setting a default function to be applied to all of your existing datatips. You could also suggest making this feature available [Contact tech support].

List of factory CreateFcn functions

factoryAnimatedlineCreateFcn

factoryAreaCreateFcn

factoryArrowshapeCreateFcn

factoryAxesCreateFcn

factoryAxestoolbarCreateFcn

factoryBarCreateFcn

factoryBinscatterCreateFcn

factoryBubblechartCreateFcn

factoryBubblelegendCreateFcn

factoryCategoricalhistogramCreateFcn

factoryColorbarCreateFcn

factoryConstantlineCreateFcn

factoryContourCreateFcn

factoryDoubleendarrowshapeCreateFcn

factoryEllipseshapeCreateFcn

factoryErrorbarCreateFcn

factoryFigureCreateFcn

factoryFunctioncontourCreateFcn

factoryFunctionlineCreateFcn

factoryFunctionsurfaceCreateFcn

factoryGeoaxesCreateFcn

factoryGraphplotCreateFcn

factoryHggroupCreateFcn

factoryHgjavacomponentCreateFcn

factoryHgtransformCreateFcn

factoryHistogram2CreateFcn

factoryHistogramCreateFcn

factoryImageCreateFcn

factoryImplicitfunctionlineCreateFcn

factoryImplicitfunctionsurfaceCreateFcn

factoryLegendCreateFcn

factoryLightCreateFcn

factoryLineCreateFcn

factoryLineshapeCreateFcn

factoryParameterizedfunctionlineCreateFcn

factoryParameterizedfunctionsurfaceCreateFcn

factoryPatchCreateFcn

factoryPolaraxesCreateFcn

factoryQuiverCreateFcn

factoryRectangleCreateFcn

factoryRectangleshapeCreateFcn

factoryScatterCreateFcn

factoryStairCreateFcn

factoryStemCreateFcn

factorySurfaceCreateFcn

factoryTextCreateFcn

factoryTextarrowshapeCreateFcn

factoryTextboxshapeCreateFcn

factoryTiledlayoutCreateFcn

factoryUibuttongroupCreateFcn

factoryUicontainerCreateFcn

factoryUicontextmenuCreateFcn

factoryUicontrolCreateFcn

factoryUiflowcontainerCreateFcn

factoryUigridcontainerCreateFcn

factoryUimenuCreateFcn

factoryUipanelCreateFcn

factoryUipushtoolCreateFcn

factoryUisplittoolCreateFcn

factoryUitabCreateFcn

factoryUitabgroupCreateFcn

factoryUitableCreateFcn

factoryUitogglesplittoolCreateFcn

factoryUitoggletoolCreateFcn

factoryUitoolbarCreateFcn

[Justin Dietz]

That does something to answer my question. But what command would I use to assign the function to all datatips? If I can't use set(groot,...) then I don't know how to make that assignment.

And I suppose another question that occurs to me when reading your answer: What's the diference between changing a 'default' value and changing a 'factory' value. E.g. in my startup.m file when I execute set(groot,'defaultLineLineWidth',1.5), should I instead by setting 'factoryLineLineWidth' or something? Is there a difference between those two properties?

[Adam Danz]

You would manually assign the function directly to the createFcn property of the datatips. Also see Callback Definition. If you need any help with that, let me know.

To address your secton question, factory values are the built-in default values and when you change them, they are stored as a default value.

See Default property values from the documentation.

[Justin Dietz]

Yeah I'm gonna need some more help with assigning the function. I've tried what was specified in your default property values link. Using its nomenclature, the string that specifies what I want should be 'defaultDataTipCreateFcn', but it tells me that datatip is an invalid class name.

Also, your createFcn link specifies that "Setting the CreateFcn property on an existing component has no effect."

So it would seem that I need to set some kind of 'default' parameter in order for this to work for newly created datatips, but that's precisely what I can't seem to get working properly.

[Adam Danz]

@Justin Dietz, after re-reading your question, I don't think you really want the CreateFcn which is called when the datatip object is created which is why you must define that function within the same line that you define the datatip. I'm going to add a new answer.

Answer 2

[Adam Danz]

1. > I'm trying to add callback code to a scatterplot that activates when the use clicks on a data point
2. > I want to set a default value for this callback function so it executes whenever any new datatip is created
3. > My primary question is how do I assign a callback function that is executed whenever any datatip is created

These are two different questions so the goal is not clear.

In question 1, you want a function that responds to pressing a scatter plot object. That would involve assigning a ButtonDownFcn to the scatter object.

In questions 2 and 3, you want a datatip to appear when you click a scatter object which would prevent use of the ButtonDownFcn (you can't have both).

It sounds like you want a datatip to appear when you click a scatter point and you want some function to be evoked as well. If so, the CreateFcn is not what you're looking for since that is evoked when a datatip object is created which isn't the same as when a datatip object appears after clicking on a point (that's why the CreateFcn must be defined when creating the datatip, otherwise it has no effect). Instead, you want the UpdateFcn of the DataCursorManager or you could use the DataTipTemplate depending on what you want to do. To understand the difference between the two, see Setting precision of datatip text.

There are lots of demos listed here and in the documentation. But I don't think there are default options for these functions, however. If there's a common function you'd like to apply, you could create the function in a separately m-file and then assign the function to all of your functions/scripts.

Answer 3

[Massimo Ciacci]

%% setTips_CallBack.m
% call only when figure created and one line drawn, wo any tips
fh  = gcf;
ax_hdl = gca;
% make sure there are NO dta tips yet
% this cursorMode will only work for every new clicked tip 
cursorMode = datacursormode(fh);

axChild   = get(ax_hdl,'Children');
allCurves = findobj(axChild,'type','line');
hTarget   = allCurves(1);

% set format later read back from inside customDataTipCallBack as this:
% output_txt = customDataTipCallBack(src,evt)
% axh = ancestor(evt.Target,'axes');
% fmt_x = axh.UserData.fmt_x;
% fmt_y = axh.UserData.fmt_y;
fmt_x = '%2.2f';
fmt_y = '%2.2f';
chopY = 1e-7;
ax_hdl.UserData.fmt_x = fmt_x;
ax_hdl.UserData.fmt_y = fmt_y;
ax_hdl.UserData.chopY = chopY;

% register callback
set(cursorMode, 'UpdateFcn',@customDataTipCallBack);  

% create a tip somewhere (no need)
% % hDatatip = cursorMode.createDatatip(hTarget);

[Massimo Ciacci]

Don't know why but the text I had written preceding the code is gone... Now I will be shorter.

The code above (setTips_CallBack.m) is is how I register my own callback function.

customDataTipCallBack can be found here:

https://nl.mathworks.com/matlabcentral/fileexchange/72849-add_datatips

setTips_CallBack.m comes with it's own test bench: test_setTips_CallBack where you create a plot and then with the mouse add tips using your custom callback.