With Ubuntu 18.04 OpenCV 4.1.0. I make a link to solve this problem. ln -s /usr/local/include/opencv4/opencv2/ /usr/local/include/opencv2

ln -s /usr/local/include/opencv4/opencv2/ /usr/local/include/opencv2

Thanks, this approach solved the issue for me on macOS Catalina and openCV installed via homebrew: ln -s /usr/local/Cellar/opencv/4.2.0_1/include/opencv4/opencv2 /usr/local/Cellar/opencv/4.2.0_1/include/opencv2

I have done some more testing on mac and windows, but, spoiler alert, I am stuck with the same issues as everyone else. But for what its worth here are my findings:

• The issue started with 5.3.0. The version before (5.2.0) worked fine for me
• Regarding the opencv2/core.hpp file not found error, it seems that the defaultIncludeDirs are defined correctly, but somehow might not be triggered? - see install.js
• Regarding the Symbol not found error, I am not exactly sure, but believe it has something todo with the libraries not being set/linked correctly. Maybe @justadudewhohacks has some ideas to point me into the right direction?

Details

My setup

• I have set up my own simple electron opencv4nodejs test repository built on electron-react-boilerplate as I had some issues with opencv-electron
• I am using the autoBuild feature
• I have tested on mac and windows, both with opencv 3 and 4

My tests To get around the

In file included from ../cc/opencv4nodejs.cc:2:
In file included from ../cc/ExternalMemTracking.h:1:
../cc/macros.h:2:10: fatal error: 'opencv2/core.hpp' file not found
#include <opencv2/core.hpp>
         ^~~~~~~~~~~~~~~~~~

error I had added the include directory path in theapp/node_modules/opencv4nodejs/binding.gyp

"include_dirs" : [
	"<!@(node ./install/parseEnv.js OPENCV4NODEJS_INCLUDES)",
	"cc",
	"cc/core",
	"<!(node -e \"require('nan')\")",
	"<!(node -e \"require('native-node-utils')\")",
	"<(module_root_dir)/../opencv-build/opencv/build/include",
],

I have used the autoBuildOpencvVersion to test if opencv4 makes any difference, but it did not. For opencv 4 the include path is slightly different

	"<(module_root_dir)/../opencv-build/opencv/build/include/opencv4",

After having fixed the include issue electron-rebuild ends successfully. But when running the application, the Symbol not found error pops up.

Uncaught Error: dlopen(/Users/jakobschindegger/Documents/Electron/electron-opencv4nodejs/app/node_modules/opencv4nodejs/build/Release/opencv4nodejs.node, 1): Symbol not found: __ZNK2cv12MatAllocator23getBufferPoolControllerEPKc
  Referenced from: /Users/jakobschindegger/Documents/Electron/electron-opencv4nodejs/app/node_modules/opencv4nodejs/build/Release/opencv4nodejs.node
  Expected in: flat namespace
 in /Users/jakobschindegger/Documents/Electron/electron-opencv4nodejs/app/node_modules/opencv4nodejs/build/Release/opencv4nodejs.node

This is where I am stuck now. I am not sure how to solve this error. I had looked at this issue where it seemed that they solved the error, but their solution did not work for me. Maybe because they were not using the autoBuild feature?

Edit: My last suggestion was using the install from opencv’s site, not chocolatey. I actually don’t think that was the cause, instead I had to use opencv4nodejs@5.1.0. Note that this will not work if you just change your package.json entry to ^5.1.0, as this will simply install 5.5.0 again.

As to why windows freaks out with 5.5.0, I couldn’t tell you, but I hope this helps someone.

maybe you should try @u4/opencv4nodejs this original opencv4nodejs is not maintained anymore.

Facing the same issue on MacOS Monterey, while running npm i opencv4nodejs and none of the above mentioned steps worked. Installed opencv using brew after setting export OPENCV4NODEJS_DISABLE_AUTOBUILD=1 as mentioned here

@fakob Hi, I got the same issue as yours. Did you figure out the workaround? 🙇

Error: dlopen(/Users/zcmgyu/Documents/LongWorkingSpace/matt/opencv4nodejs/build/Release/opencv4nodejs.node, 0x0001): symbol not found in flat namespace ‘__ZNK2cv12MatAllocator23getBufferPoolControllerEPKc’

ln -s /usr/local/include/opencv4/opencv2/ /usr/local/include/opencv2

Thanks, this approach solved the issue for me on macOS Catalina and openCV installed via homebrew: ln -s /usr/local/Cellar/opencv/4.2.0_1/include/opencv4/opencv2 /usr/local/Cellar/opencv/4.2.0_1/include/opencv2

I tried to do this approach on macOS Catalina 10.15.6 and it didn’t work

With Ubuntu 18.04 OpenCV 4.1.0. I make a link to solve this problem. ln -s /usr/local/include/opencv4/opencv2/ /usr/local/include/opencv2

Having this issue when creating a symlink

dlopen(/Users/ianoderon/Desktop/dev/cam/node_modules/opencv4nodejs/build/Release/opencv4nodejs.node, 1): Symbol not found: __ZNK2cv12MatAllocator23getBufferPoolControllerEPKc
  Referenced from: /Users/ianoderon/Desktop/dev/cam/node_modules/opencv4nodejs/build/Release/opencv4nodejs.node
  Expected in: flat namespace
 in /Users/ianoderon/Desktop/dev/cam/node_modules/opencv4nodejs/build/Release/opencv4nodejs.node

I’m using mac osx 10.14.6

The same problem here. Seems that electron-rebuild can’t include opencv2/core.hpp and i can’t find opencv2/core.hpp myself. Is there any solution to this problem?