QGLWidget not found when compiling OpenCV on Manjaro

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I’m trying to build OpenCV version 4.5.4 on my new Manjaro Linux installation. I’m trying to build it with QT support and the contrib addons.
Around 35% into the build I get the following error:

In file included from /home/rickiewars/git/.download/dev/opencv_packages/opencv/modules/highgui/src/window_QT.cpp:47:
/home/rickiewars/git/.download/dev/opencv_packages/opencv/modules/highgui/src/window_QT.h:51:10: fatal error: QGLWidget: No such file or directory
   51 | #include <QGLWidget>

I’ve installed the qt5-base package with pacman and the include file can be found in /usr/include/qt/QtOpenGL/QGLWidget

I’ve changed the following variables in CMakeCache.txt:

  • WITH_OPENGL → ON
  • WITH_QT → ON
  • OPENCV_ENABLE_NONFREE → ON
  • BUILD_opencv_rgbd → OFF
  • OPENCV_ENABLE_ALLOCATOR_STATS → OFF
  • ENABLE_PRECOMPILED_HEADER → OFF

I hope someone can help me compile this before my next class begins. :slight_smile:

My thanks in advance!

2

if you don’t specifically need the fancy Qt variant of imshow, you can just build OpenCV without Qt, and it’ll use GTK or something. that’ll be a plain imshow without decorations.

I’d guess that your Qt is too new (or too old?) for the Qt highgui backend of OpenCV…

I see mention of deprecation of some headers where QGLWidget lives. the old header is called QtOpenGL, the new one (for QGLWidget) is QGLWidget

from the error it looks like OpenCV includes the correct header… so I conclude that you have an ancient Qt? or it doesn’t find Qt in general, which would be a different problem.

3

Hi, thanks for the fast reply.

I needed the qt version because all of the examples i got from class are written with qt.

Fortunately i fixed all my problems by installing python-opencv on my system.
Looks like i was missing a dependancy or something.

Sorry for late response i’ve fixed my issue but i just saw the post was made visible, when i fixed my issue the post was still marked as hidden.

Thanks anyway!