Im making an aplication for image filtering and Im sucesfully using the CImg.h library to help with the task, but as you might know the fft isn't for any image and I need to activate the use of the fftw3 library to overcome this. And I dont have any clues on how to do that (I'm super new with Qt), if it helps somehow to the explanation I was able to do that on ZinjaI but for this new aplication I had to move to Qt to get a more friendly GUI.
Im using Qt 5.0.2 (32 bits) / Qt creator 2.7.0 on windows with minGW.
Thanks a lot for taking the time to read it and any help would be greatly appreciated.
Extra: Not as important as the other but if I also can learn how to avoid having the cmd.exe windows poping in front of my GUI would be cool :) (I guess the CImg.h functions make it pop, but not sure)
Related
Hi I have a debian image on BBB I have already installed QT creator on B^3 but the problem is whenever I try to start a new project in qt creator, couldn't see any option of kit. Infact when i add qmake and compiler path the application throws error.
What can I do to solve the problem. Can i directly get the full pack of SDK from qt.io/download ?
You must compile Qt libraries for your device (BBB) on your own, using specified compiler. You can find more information on this topic, here:
Qt Cross-Compilation Options
As soon as you compile Qt libraries for your device, you must move them to appropriate directories (on your BBB).
First, I would suggest learning to cross-compile, it's much faster & more easily maintained when you want to move to new versions. There's a ton of documentation and community around doing this. Windows & Linux both of which are probably dated, but info is still relavent. I've heard it's much easier from a linux host, but that could be biased.
That being said, if you don't want to cross-compile I believe you can simply install the qt embedded libraries. This question may offer some good advice. Once you have the libraries installed, you should be able to use qmake directly to create the Makefile for your project, then you can use cmake, or g++, etc.. to do the actual compiling.
You're likely going to work in command line though, I'm not sure you can run QT Creator on the BBB directly. I could be wrong.
I have a program that I need to edit that was developed with Qt version 5.0.1. Will the program still work correctly if I just grab the newest version and edit the program with that? Or am I better off getting the old version from the Qt archive?
Qt 5 is not 100% compatible with previous versions, so probably you will have to make some migration stuff. This little transition guide is your friend!
Whenever I use OpenCV's cv::imshow alongside with Qt's QApplication, I get this error:
Gtk-WARNING **: gtk_disable_setlocale() must be called before gtk_init()
I did some searching and ended up reading more and more about stuff I don't fully understand, but got some ideas how OpenCV and GTK+ are connected. And since the warning is obviously an instruction to call something before something, I included gtk.h and called gtk_disable_setlocale(), but ended up with even more errors.
My code runs despite the warning without any problem, but it really bugs me! And I assume that behind the warning, there are some essential stuff a programmer should understand. So maybe somebody can explain the whole thing in a way an advanced newbie can understand? ;)
Edit:
I'm using ubuntu 12.10, OpenCV 2.4, GTK 2.24.13 and qmake -v tells me
QMake version 2.01a
Using Qt version 4.8.3 in /usr/lib/x86_64-linux-gnu
If you are going to use Qt windowing system, it's best to avoid creating OpenCV windows alongside with Qt windows.
Convert IplImage or cv::Mat to QImage and draw that on a Qt window. Check cvImage, a simple Qt/OpenCV example that displays an image loaded with OpenCV on a Qt window, and also shows the RGB values of a pixel based on mouse coordinates.
I am currently using QtCreator 2.4.1 with Qt 4.7.4 development libraries (in Ubuntu) and am trying to track down a bug which after profiling with valgrind seems to occur internally within QGraphicsView::paintEvent(…) method
To help isolate this problem I would like to step into the Qt sources. Having done some searching through both the Qt forums and stack overflow and have not being able to find a way to integrate the sources with my version of QtCreator.
I have currently tried downloading the sources via the QtSDK manager and adding a “Source Path Mapping” within Tools->Options->Debugger. I am sure that this step is where I am making a mistake as I am unable to even switch to source when viewing internal Qt header files i.e. from QGraphicsView.h
I have so far tried adding the following Source Path Mappings
Source Path=/var/tmp/qt-src
TargetPath=/home/paul/QtSDK/QtSources/4.7.4
and
Source Path=/var/tmp/qt-src
TargetPath=/home/paul/QtSDK/QtSources/4.7.4/src
Neither works.
I have also tried building Qt directly from source, adding this to my "Qt versions" list within Qt Creator and creating a new project configuration using this version. This also did not work.
Likewise I have tried adding the src folders to my gdbinit file. This also fails to work.
I am completely lost with this.
Paul
Someone asked a similar question here: Need to step into Qt sources (my IDE is Qt Creator).
Someone else asked about Valgrind errors with Qt here: Suppression files for Qt memory leaks with Valgrind
And here is a little more info about Using Valgrind with Qt Creator along with some explanation about how to read the results. Its a little dated from late 2010.
Related Suggestions
I wouldn't debug the QGraphicsView class just because of all the effort to make it work or find the problem might be for nothing... Qt is moving to using the SceneGraph as the backend for QML and the rendering engine for QGraphicsView might become obsolete.
Updating to the latest stable build of the Qt libraries may make a big difference for QGraphicsView.
If you post the valgrind error you are getting to the Qt Trolls, someone might be able to explain what is going on for you.
There are other debugging techniques besides the traditional debugger. I've been programming in Qt in Windows (without valgrind) and with a large multi-threaded application, that loads a bunch of Dll's. I've had to put some faith into the Object Tree Model clean up and work on all the new calls I put in. Most of the time I just use QDebug to find errors. Then I am also using a combination of qInstallMessageHandler() with QDebug to implement decent logging for the hard to track bugs.
See also Qt Debugging Techniques.
Is there a quick, straightforward way to make a Qt application into an executable? I attempted to follow the instructions at http://doc.qt.digia.com/4.1/deployment-windows.html but have been unsuccesfull thus far; I'm unable to Any help would be much appreciated. Thanks!
I always use CMake to build Qt projects, it's easy, free and cross platform. Guide : Compiling Qt4 apps with CMake. CMake also come with CPack to easly make installer for Windows, Mac and Linux.
I agree with chmod700 about the Qt Creator suggestion, it's not my favorite IDE but it's still really nice and easy.
Do you mean an installer package? I assume you are able to compile, link, and run your app and you mean how do you package it up for others.
http://installbuilder.bitrock.com/ <-- special handling of Qt based projects but costs $
http://www.jrsoftware.org/isinfo.php <-- my personal favorite and it's free (can be rough to learn advanced features though)
Though if you mean how do you build your app, you may want to try the new Qt Creator (http://www.qtsoftware.com/products/appdev/developer-tools/developer-tools#qt-tools-at-a) which will setup build targets for you and really makes desktop Qt dev a snap. Also if you're still using 4.1, you can now use 4.5 under the LGPL on all platforms making it almost a no-brainer to upgrade.
I'm not sure if I understand your problem. Assuming you're using MinGW, it's really easy and quite straightforward:
get the Qt sources and unpack them to some folder (f.e. c:\Qt\4.5.0-static)
install MinGW. Make sure the MinGW executable folder is in the %PATH% variable.
open a cmd windows, go to the Qt sources and run configure -static. You can add other config options if you like to, but usually you don't need that.
when building Qt finished, go to your application sources, open a cmd window and run the qmake of your built Qt installation -- i.e. c:\Qt\4.5.0-static\bin\qmake in the example given above.
run make
you get a statically linked binary in the end (you might want to check it with Dependency Walker).
Doing the same using Visual Studio is pretty similar.
Or do you want to build dynamically and create an installer package?