OpenCV GTK+2.x error

Question

I had installed OpenCV following these steps (). After trying to compile one examples,i got this error :

OpenCV Error: Unspecified error (The function is no         


        

Answer 1

In order to improve @Nic Szer's answer I want to explain how to fix this error on Mac OS in three simple steps.

1. Remove installed OpenCV version to avoid mess up later

   pip3 uninstall opencv-python 
   

2. Lower your python version to 3.5 (current version 3.6 has problems with conda which we will use to install OpenCV)

   conda install python=3.5
   

3. Finally, use conda to install working version of OpenCV

   conda install -c menpo opencv3 
   

And then voila: OpenCV will start working on your Mac OS(Siera 10.12.4).

Answer 2

If someone else ends up here like I did after installing OpenCV using vcpkg on Ubuntu, there is a known issue with vcpkg where you'll end up with the exact same error message as the top of this post with no access to highgui:

OpenCV(4.3.0) Error: Unspecified error (The function is not implemented. Rebuild the library with Windows, GTK+ 2.x or Cocoa support.
If you are on Ubuntu or Debian, install libgtk2.0-dev and pkg-config, then re-run cmake or configure script) in cvNamedWindow,
file .../vcpkg/buildtrees/opencv4/src/4.3.0-0c6047baf6.clean/modules/highgui/src/window.cpp, line 634
Caught exception: OpenCV(4.3.0) .../vcpkg/buildtrees/opencv4/src/4.3.0-0c6047baf6.clean/modules/highgui/src/window.cpp:634:
error: (-2:Unspecified error) The function is not implemented. Rebuild the library with Windows, GTK+ 2.x or Cocoa support.
If you are on Ubuntu or Debian, install libgtk2.0-dev and pkg-config, then re-run cmake or configure script in function 'cvNamedWindow'

The problem is vcpkg passes in the build option -DWITH_GTK=OFF when building OpenCV. The open issue: https://github.com/microsoft/vcpkg/issues/12621

The workaround is the following:

• edit the file vcpkg/ports/opencv4/portfile.cmake
• find the line that says -DWITH_GTK=OFF and change it to say -DWITH_GTK=ON
• run ./vcpkg remove opencv4
• run sudo apt-get install libgtk2.0-dev pkg-config
• re-install OpenCV with ./vcpkg install opencv4 or whichever vcpkg command you used

Answer 3

First check whether libgtk2.0-dev is installed properly. If you have installed aptitude package manager, run the following:

sudo aptitude search libgtk2.0-dev

It should return like this:

i  libgtk2.0-dev              - development files for the GTK+ library 
p  libgtk2.0-dev:i386         - development files for the GTK+ library

You need to build the files once again.Locate your OpenCV folder. Create a new folder and name it as release. Enter into this folder. For example

cd /home/user_name/OpenCv
mkdir Release
cd Release

Now build using cmake with following command:

cmake -D CMAKE_BUILD_TYPE=RELEASE -D CMAKE_INSTALL_PREFIX=/usr/local -D WITH_TBB=ON -D BUILD_NEW_PYTHON_SUPPORT=ON -D WITH_V4L=ON -D INSTALL_C_EXAMPLES=ON -D INSTALL_PYTHON_EXAMPLES=ON -D BUILD_EXAMPLES=ON -D WITH_QT=ON -D WITH_GTK=ON -D WITH_OPENGL=ON ..

Remember to put WITH_GTK=ON during cmake. After this step enter the command,

make
sudo make install

This should resolve your problem.If you have broken dependencies for libgtk2.0-dev, then install a fresh copy of libgtk2.0-dev using aptitude.

sudo aptitude install libgtk2.0-dev

Answer 4

If you installed OpenCV using the opencv-python pip package, be aware of the following note, taken from https://pypi.python.org/pypi/opencv-python

IMPORTANT NOTE MacOS and Linux wheels have currently some limitations:

• video related functionality is not supported (not compiled with FFmpeg)
• for example cv2.imshow() will not work (not compiled with GTK+ 2.x or Carbon support)

Also note that to install from another source, first you must remove the opencv-python package

To install OpenCV in Ubuntu I followed this guide, and it worked perfectly fine: http://www.pyimagesearch.com/2016/10/24/ubuntu-16-04-how-to-install-opencv/

Answer 5

I have fixed this issue by replacing

cvDestroyWindow("showImage");

by

cvDestroyWindow("ShowImage");

Answer 6

I was using windows OS . I have gone through many stuffs in order to sort this problem . At last i just reinstall the opencv and cmake and it worked without any error.