My problem is the same as in:
OpenCV GTK+2.x error
I am facing this problem deploying my code in systems where OpenCV is available but has not been installed with GTK support. I have no control over OpenCV installation in these systems.
How can I discriminate where OpenCV is compiled without GTK support from C++ code, possibly without relying on catching exceptions? I would simply avoid calling imshow in these cases.
you could check dependencies by executing ldd opencv-lib and parse the output using e.g. regex to check for some kind of gtk libs.
Or use this approach: linux/gcc: ldd functionality from inside a C/C++ program
setenv("LD_TRACE_LOADED_OBJECTS", "1", 1);
FILE *ldd = popen("/lib/libz.so");
Related
I am working in a C++ project with OpenCV in Windows and VSCode. The project is meant to be built and run in a Docker Container, thus I do not need OpenCV in Windows. If needed, I use OpenCV as installed in WSL.
VSCode complains all the time in #include <opencv2/opencv.hpp> about not being able to find the library, and consequently it refuses to look for errors along the rest of the file.
I do not need OpenCV and I know that the compiling process can become tedious over Windows, so I would like VSCode to ignore this error and go on checking the rest of the files. Having IntelliSense working with OpenCV classes would be ideal.
Is there some way to have this without installing OpenCV in Windows?
This sounds like a good use case for VS Code Dev Containers. Dev containers let you use a docker file to define an isolated linux based development environment—including which tools and libraries are installed—in a reproducible way that does not effect your local machine.
Check out the Dev Container docs and the example c++ dev container for help getting started. If you already have an OpenCV docker image, you can use this as the base for your dev cotntainer
If you are using VSCode on Windows and would like it to OpenCV that is in WSL, you will need to install an extension on VSCode called Remote - WSL, developed by Microsoft.
You'll be able to use Linux specific toolchains, utilities and even run Linux-based applications directly from VSCode on Windows..
I am using Qt & OpenCV on a new project am about to compile OpenCV to work with MinGW.
A thought has arose that I can compile the OpenCV libs with Qt support but I don't really understand why I would want to do that. If I don't compile the libs with Qt support I can still route cv::mat to a QImage using a method like this.
So what am I missing? What value is provided in compiling Qt with OpenCV?
I have searched online and pages like this, this & this (from searching "why compile OpenCV with Qt") only show me how to compile with Qt and not why.
LE: misunderstood the question
WITH_QT option is used by highgui module to create windows using qt, so the QImage to cv::Mat conversion and vice-versa will work no matter how WITH_QT option is set.
First some clarifications: you are not compiling OpenCV with Qt, Qt is not a compiler so you can't compile anything with it.
Qt is a C++ library (it's called a framework because it imposes some design some rules to your application source code, but basically it's a C++ library, just like OpenCV).
Now, in C++ world* to use some libraries together you need to build those libraries with the same compiler (and in some cases even the same compiler settings), so must decide which C++ compiler you want to use and get both Qt and OpenCV built with the same compiler not necessarily build by you, binaries can be obtained from their websites.
If you want to use MinGW you will need to build OpenCV with MinGW compiler, because OpenCV (at least, version 2410) comes build only with Visual C++ version 10, 11, 12 - that means Visual Studio 2010, 2012 and 2013.
So if you decide to use some Visual Studio version, depending on version you choose, you might be able to use Qt with OpenCV without having to build neither yourself, but if you want MinGW compiler you need to build OpenCV with MinGW.
*you can get away with it if your libraries only export a C interface, but that is not the case with neither Qt nor latest OpenCV versions.
//if you want more details about this use your favorite internet search engine to search for: c++ binary compatibility and or c++ abi
You'd like to compile OpenCV with Qt for at least two reasons:
it gives you the zoom (mouse wheel) in imshow
it gives you the pixel RGB value when hovering over this pixel
Without WITH_QT, you just have a bare window, with none of these features (and you'll miss extra buttons too, like Save the picture), which make the image processing debugging more tedious.
I wrote cpp code using OpenCV library, compiled it with cmake and everything works good on Ubuntu. Now I need to compile the same code for Windows 7 or higher. I have no experience with cross compiling, is there any at least relatively easy and reliable way how to do it? Probably somehow change the CMakeLists or so?
Building OpenCV library for Windows seems according official tutorial pretty demanding.
After big struggle with me and OpenCV I finally found this tutorial:
OpenCV with MinGW on Eclipse Tutorial (Scroll to "OpenCV - with CMake & MinGW")
I did everything as it has been written, but everytime I try to launch application it stops to respond just after few seconds and Windows alert communicate is shown. I noticed, that I can freely run standard C++ programs and include headfiles, but after single line of OpenCV code it fails to work properly. Also there is no information about error.
why don't you try the official tutorial http://docs.opencv.org/doc/tutorials/introduction/linux_eclipse/linux_eclipse.html#linux-eclipse-usage
this is the official site in opencv documentation which should get you started, it includes tutorials to get you started on lots of other platforms
http://docs.opencv.org/doc/tutorials/introduction/table_of_content_introduction/table_of_content_introduction.html#table-of-content-introduction
I also had a touch time getting OpenCV running but finally I found something that worked (I use Qt Creator as my IDE, not Eclipse, but maybe the problem and solution is similar).
At first I tried to download OpenCV 2.4.8, but I found it didn't include any MinGW binaries. I followed a forum on the web and installed CMake, but it seemed like OpenCV 2.4.8 didn't contain the CMake target for MinGW. After reading some more forums, I downloaded OpenCV 2.4.3 and was able to use CMake along with MinGW 4.8 (version that came with Qt 5.2) to build OpenCV. This got me to a point where I could compile my programs and attempt to run them. Some of the pure c commands even worked like cvLoadImage, but any of the c++ commands like imread or Mat::zeros(3,3, CV_8UC1) would cause a crash.
I tried building openCV a few more times with different options. Some sites suggested turning off SSE and SSE2 or building the debug version, but none of this worked for me.
Finally I ended up downloading TDM-GCC-32. I downloaded the on demand installer and made sure to get the dw2 version of the compiler (since a while ago I spent some time dealing with dw2 vs sjlj incompatibilities). Finally I rebuilt OpenCV with the TDM-GCC and also set TDM-GCC as the compiler in Qt Creator. This ended up being the fix.
I think there are some incompatibilities between the reference counting / allocation code used by the OpenCV Mat type and some versions of MinGW. I say this because all my crashes seemed to come from sections of code using the openCV matrix. (It seemed like it wasn't properly initialized or something). Switching to the TDM-GCC compiler fixed the problem.
is there any Binary Decision diagram (BDD) is available in windows.i tried to run cudd in vc++6.0..which is mention link
http://web.cecs.pdx.edu/~alanmi/research/soft/softPorts.htm
but it isn't working properly.i get compiler error while running a sample code
I compiled CUDD for Windows, but using MinGW not a Microsoft environment. My goal was that compiler since I use Dev-C as IDE.
I did a first try using Cygwin, but with no luck. The second try was with MSYS, an environment to run unix commands that come with MinGW for Windows. Note that CUDD uses a couple of POSIX libraries (such as ). Luckily they are used only in two secondary functions: CPU stats and a kind of fork that I didn't fully understood. Since I didn't need those, I simply commented the portion of code (in util/cpu_stats.c).
Then you only need to write a Makefile for MinGW in order to link the library!
If you need it, I can send to you the library already compiled.