Using impixelinfo with appDesigner

Question

Roger Breton 2021-12-27

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1618315-using-impixelinfo-with-appdesigner

回答： Rishabh Singh 2022-1-12

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I am running into the following error with appDesigner, when trying to retrieve the pixel info an an image component :

This is the app interface :

All I want to achieve, at this stage, is to get some information about the pixels at the mouse position.

I thought of using impixelinfo but it needs some argument? I tried :

impixelinfo(app.myImage);

But that's when I get the above error message. I read somewhere that impixelinfo does not work with appDesigner?

Eventually, I would like to capture the mouseover and mouseclick events so that I can display not only the image RGB values but also, and more importantly, the CIE Lab values. Ultimately, I would like to turn mouseclicks into a selected 3D points in the scatter3 plot on th right... Tall order for a Matlab and appDesigner newbie like me -- I know.

Any help is appreciated.

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Roger Breton 2021-12-29

Just want to say that I'm studying the code here :

https://www.mathworks.com/matlabcentral/answers/775147-how-to-create-mouse-movement-event-on-uiaxes-in-app-designer-to-catch-cursor-location-on-the-axes

There is a LOT I have to learn but, withe help of the debugger, it helps a lot.

So far, I ran the code at the above link and I can see that this partly does what I need to do, which is to return some values in response to a mouseover movement over some graphic object. To wrap one's brain around the used symbols is not for the faint of heart... Needless to say, I'm discovering a whole world but I'm not totally lost, programming wise. I just have not a "mental" map of Matlab's object model... But I'm getting there.

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Answer 1

Rishabh Singh 2022-1-12

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链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1618315-using-impixelinfo-with-appdesigner#answer_873000

Hey,

A possible workaround for your problem could be using a figure window outside your app.

function ButtonPushed(app, event)

img = app.cam.snapshot();

imshow(img);

hp = impixelinfo();

set(hp, 'Position', [5 1 300 20]);

end

Here I have used a "ButtonPushed" callback to trigger the figure window, and there you can use "impixelinfo". You can also explore "datacursormode" and "getCursorInfo" for picking up data points using cursor.

Hope this helps.