Get coordinates of dicom image by clicking anywhere on image in Qt

[jsulm]

@pvirk said in Get coordinates of dicom image by clicking anywhere on image in Qt:

With mousepressevent, can i get coordinates also?

Yes, https://doc.qt.io/qt-5/qmouseevent.html#pos
Example: https://doc.qt.io/qt-5/qtwidgets-widgets-scribble-example.html

[mrjj]

@pvirk said in Get coordinates of dicom image by clicking anywhere on image in Qt:

XYZ coordinates of dicom images

Just to be clear. the mousepressevent gives your the x,y in pixels.
There is no Z.

[pvirk]

@jsulm Thank you.

I have tried the example from
https://www.youtube.com/watch?v=5dI0u84VGoY here.
It gives me x,y coordinates wherever I double-click on Qt window.

But if I put QWidget (specifically I want to use QVTKWidget where I will get my dicom images) in .ui file, then I don't understand what to change in above example, to get x, y coordinates only in that particular QWidget/QVTKWidget window (not outside of it). And then save it so I can use it for further processing.
Could you please tell me in details?

Thanks a lot again.

[jsulm]

@pvirk Subclass QVTKWidget, override mousePressEvent() in your subclass and use that one instead of QVTKWidget
https://vtk.org/doc/nightly/html/classQVTKWidget.html#aa92a6e9081f134c41ef985a44d7e90a6

[pvirk]

Sorry, but I don't know how to do it. I am new to Qt.
Could you please explain me in steps?
What exact changes I have to do, do I need any header file for it?

[jsulm]

@pvirk said in Get coordinates of dicom image by clicking anywhere on image in Qt:

I am new to Qt

It's actually C++

class MyWidget : public QVTKWidget
{
protected:
    void QVTKWidget::mousePressEvent(QMouseEvent * event) ;
}

And now use this MyWidget class instead of QVTKWidget.

[pvirk]

I did this, but do not understand what is wrong in it.
Do I need any header file?

[KroMignon]

@pvirk said in Get coordinates of dicom image by clicking anywhere on image in Qt:

Do I need any header file?

At least you must include the definition of QVTKWidget ==> maybe #include <QVTKWidget> or #include <QVTKWidget.h> ?

[jsulm]

@pvirk Sorry, it needs to be

class MyWidget : public QVTKWidget
{
protected:
    void mousePressEvent(QMouseEvent * event) ;
}

[SGaist]

You are just mixing unrelated stuff.

@jsulm provided you with the minimal class definition to get started.

If you don't know how to do subclassing, then please, start by going through basic C++ tutorials before going further. You'll save yourself a lot of trouble.

[pvirk]

Okay. I will check C++ tutorials. Thank you so much everyone.

[pvirk]

Hello,
I have tried example to understand mousepressevent in QWidget.
But I am facing some problem, when I use it in my code.
I used one QVTKWidget to check coordinates with mousepressevent, and it worked. But when I use that same QVTKWIdget to load dicom data using vtkRenderWindow and interactor, it shows following errors. Here "matDisplay" is class I created for mousepressevent.

1. Error C2039 'SetRenderWindow': is not a member of 'matDisplay'
2. Error C2039 'GetInteractor': is not a member of 'matDisplay'

I need Render Window and Interactor to render dicom images.

So, how can I use mousepressevent in QVTKWidget?

Please help and thanks in advance.

[SGaist]

What is matDisplay ?

[mrjj]

Hi
Can you show your exact code for matDisplay ?

It should have those functions
https://github.com/Kitware/VTK/blob/master/GUISupport/Qt/QVTKWidget.h

[pvirk]

Hello,
'matDisplay' is class i created for mousepressevent.

then I used
QObject::connect(ui->qvtkWidget_3, SIGNAL(sendMousePosition(QPoint&)), this, SLOT(showMousePosition(QPoint&))); in my other .cpp file.

This thing works. Here I used subclass QWidget. But if I use QVTKWidget subclass, then build succeeded but then my program crashes.
But when I used this qvtkwidget_3 to get my dicom data, then shows me those errors.
Anyone has any idea about it?

[mrjj]

@pvirk
Hi
It has to inherit from QVTKWidget
as else it wont be right for the other classes as the errors shows:

Error C2039 'SetRenderWindow': is not a member of 'matDisplay'
Error C2039 'GetInteractor': is not a member of 'matDisplay'

This is correct as a QWidget does not have them. It comes from
QVTKWidget.

You have to use that QVTKWidget find out why it crashes.
I would guess you might forgot
to call
: QVTKWidget(parent) and maybe had QWidget(parent) from before.
so that the QVTKWidget was not ok setup. = crash

[pvirk]

Hello,
I changed it to :QVTKWidget in both my .h and .cpp files of matDisplay class.
The reason for crashing was, In .ui file the qvtkwidget was not promoted to QVTKWidget.h file. I promoted to it and now there is no crashing.
But now the problem is I cannot use my matDisplay.h also as promoted class in .ui file. Because of that I cannot get coordinates of that widget.
How can I use both my QVTKWidget.h and matDisplay.h as promoted classes for qvtkwidget in .ui file?
I double-checked both of them in promoted widget option, but still it is only promoted to qvtkwidget.h only?

[mrjj]

HI
you can not promote a widget to 2 different widgets.
That is not possible but would be cool if it could work :)
You can have 2 widgets but im not sure why you want that.

From the code, matDisplay is your version of QVTKWidget so
you should place a QWidget and promote that to matDisplay.

And it then contains your extra code for mousePress and all of QVTKWidget

[pvirk]

I tried this way.
I used QWidget for my matDisplay class and promoted to matDisplay.
But when I use that same QWidget in my code to load image, It shows those same errors.
Error C2039 'SetRenderWindow': is not a member of 'matDisplay'
Error C2039 'GetInteractor': is not a member of 'matDisplay'

(because it is promoted to only matDisplay and not to QVTKWidget)

I need only one widget where i can load dicom image (which are connected to render window and interactor in my code) and use that same widget to get coordinates of that dicom image.

Sorry I tried all ways, but don't understand how to achieve these both things using only one widget.
Kindly please help me.

[SGaist]

Inherit matWidget from QVTKWidget.