How to use the ImplicitPlaneWidget2 inside QML?

Synfony · February 4, 2020, 3:15am

Hi,
I am using VTK render window inside a QML item (i.e. in a QtQuick application).
Rendering is working fine for the ImplicitPlaneWidget2 as well as mouse interaction like mouse wheel, camera rotate etc. But I can’t enable the interaction with the plane and the orientation handle. It appears that I need to use the QVTKInteractorAdapter class (https://vtk.org/doc/nightly/html/classQVTKInteractorAdapter.html) to connect QtEvent (generated from QML item) with the VTK interactor. But, I am not sure if/how should I do that.
Is there any other way to allow the QML based application to do that?

I appreciate if you could help with a code snippet.

Thanks for your help!

Paulo_Carvalho · February 5, 2020, 1:51pm

Hello, friend,

I suggest reading a bit about it here: https://stackoverflow.com/questions/41685872/how-to-render-programmatically-a-vtk-item-in-qml

And taking a look at these repositories for working code:

gist.github.com

https://gist.github.com/nocnokneo/c3fb01bb7ecaf437f7d6

CMakeLists.txt

cmake_minimum_required(VERSION 2.8.11)

project(VtkFboInQtQuick)

set(CMAKE_INCLUDE_CURRENT_DIR ON)
set(CMAKE_AUTOMOC ON)

find_package(VTK REQUIRED)
include(${VTK_USE_FILE})

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QVTKFramebufferObjectItem.cpp

#include "QVTKFramebufferObjectItem.h"

// Use the OpenGL API abstraction from Qt instead of from VTK because vtkgl.h
// and other Qt OpenGL-related headers do not play nice when included in the
// same compilation unit
#include <QOpenGLFunctions>

#include <QQuickFramebufferObject>
#include <QOpenGLFramebufferObject>

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QVTKFramebufferObjectItem.h

#ifndef QVTKFrameBufferObjectItem_h_
#define QVTKFrameBufferObjectItem_h_

#include <QtQuick/QQuickFramebufferObject>

class vtkGenericOpenGLRenderWindow;
class QVTKFramebufferObjectRenderer;

class QVTKFrameBufferObjectItem : public QQuickFramebufferObject
{

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kind regards,

Paulo

Synfony · February 5, 2020, 8:19pm

Hi Paulo,
Many thanks!
Your suggestions were really helpful and I am able to display outline box and the implicitPlaneWidget2 on two QML items as you can see from the attached screenshot

For the ImplitcitPlaneWidget2, camera rotation is working fine but I am not able to select the plane and change its orientation.
How do I enable all default interaction for this widget as it resides inside the QML item?

Paulo_Carvalho · February 7, 2020, 1:38pm

The fact that the 3D Widget is irresponsive certainly has to do with interactors. I don’t have any experience myself with interactors in QML, but I suppose that mouse/gesture events are not finding their way from QML to the Interactor in VTK. VTK is not aware of QML, so you have to do some tweak on your part.

After some googling, I found these:

https://vtk.org/pipermail/vtk-developers/2017-May.txt (search for “Interactor” in the page)
https://android.develop-bugs.com/article/17520230/Passing+QML+events+to+C%2B%2B+or+VTK

I suggest starting from those. Also, if it’s the case, I suggest getting acquainted with VTK Interactors in pure C++ before, so you’ll understand their mechanics.

John.Stone · December 16, 2022, 5:04pm

Checkout GUISupport\QtQuick\Testing\Cxx\TestQQuickVtkItem_2.cxx in this PR
https://gitlab.kitware.com/vtk/vtk/-/merge_requests/9763