Use OpenCV C++ commands within OpenFrameworks Xcode OSX Project

Question

I would like to use OpenFrameworks for an OSX application I am building. However, I need to include some existing code that uses C++ OpenCV commands, e.g. cv::imread().

The Xcode linker throws the error Undefined symbols for architecture i386: "cv::imread(std::string const&, int). At first I tried to use the existing OpenCV code that is in ofxOpenCv, then fell back to including the OpenCV framework as I had in previous non-OpenFrameworks projects. Neither approach solved the linking problem.

As far as I can tell, the problem is that OpenCV is compiled with the libc++ compiler, while OpenFrameworks is compiled with the libstdc++ compiler.

• This presentation shows how to use C++ OpenCV commands within OpenFrameworks, but it is under Windows and not a detailed account.
• This SO Question implies that OpenCV can be recompiled under libstdc++, but the solution given is for iOS and referenced make file does not exist for OSX/linux.

Is it at all possible to use OpenFrameworks with the OpenCV C++ commands under OSX?

Answer 1

Please use Kyle McDonald's ofxCv addon, it's a much nicer interface to opencv from openframeworks. It includes Utilities to convert from cv::Mat of ofImage and back for example or helpers to draw cv::Mat straight in your of application:

#include "testApp.h"

using namespace ofxCv;
using namespace cv;
Mat img;
void testApp::setup() {
    img = imread("yourImage.png");//make sure the path is correct
}

void testApp::update() {
}

void testApp::draw() {
    drawMat(img,0, 0);
}

Also, your Undefined symbols for architecture i386: error means you probably linked against the x64(64-bit) opencv .dylib files, not the i386(32b-bit) ones.