GUI developement using Python and tkinter vs Qt and C++ - c++

I am trying to make a decision for what to use to continue developing my application.
I have some experience with C++ in the MFC Document/View architecture and have found it very frustrating. I felt I was always fighting the framework and also felt that my application didn't fit the doc/view architecture. (I now know that it probably would have fit, if I had known how to structure it that way.)
So I decided to try Python and ended up using tkinter. That was easier to learn and didn't have as many frustrations. (Though it had a few different new ones.) I think I learned a bit more about object orientation and setting up classes along the way. But am now concerned about the fact that it is an interpreted language and much slower than C++ for my purpose.
So I have been wanting to go back to C++ but not MFC. I have read a little about wxWidgets and Qt.
So here are the things I want to know:
For wxWidgets and Qt, do they use a resource editor for setting up the layout of a GUI or directly expose the code the way Python and tkinter do.
Do either wxWidgets or Qt produce any interpreted code or is everything ultimately compiled into native machine code?
Thanks

1. Both
Qt and wxWidgets have GUI builders available. In the case of Qt, an XML file is produced that is parsed by the uic to produce C++ code. wxWidgets has several designers available, they will differ between them, but I'll be surprised if they don't all follow the same pattern.
However many people, myself included, choose to hand code - there is no requirement to use the UI designers. Be careful using the term 'resource editor', as Qt has a Resource Editor and it is not used for designing GUIs.
2. Both
Qt and wxWidgets are not just GUI frameworks - they're cross-platform toolkits. In view of this, Qt is pushing for a clear separation between GUI and backend by using QtQuick and the QML language for GUI development. Qt5 still has full support for C++ widget-based development of course. wxWidgets has no equivalent that I'm aware of.
Also, if you liked Python but not tkinter, both Qt and wxWidgets have Python bindings.

Related

Qt Quick controls 2.0 for embedded device

My long term goal is to make HCI development for embedded devices, and by embedded I really mean it, not phone devices.
I've been working on Qt Widgets for a month now, avoiding Qt Quick for some reasons (I feared that QML code wasn't optimize), but yesterday I have watched this video :Youtube
The speaker says at the end : "If you're making an embedded product these days, use Qt Quick, especially now in 5.8. There's no excuse not to use Qt Quick"
But on the contrary, he explains that for embedded devices we should use c++ code, not JavaScript.
I don't really get it, does it means that I have to create all my objects in c++ code and make my architecture using Qt Quick ?
I don't really get what Qt want us to do. Is it just communication, since they don't want to optimize the old and stable Qt widgets, or is Qt Quick really the solution for embedded devices ?
I personally think that Qt is not the solution for embedded devices, as they keep evolving, changing strategy, and seems not to know where they are going.
I apologize for this non-algorithmic question, and thank you for all your answers.
I can't speak to the developer's intent, nor can I speak for other developers. I can only speak to what I understand, as a developer that has been designing embedded devices for 40 years (sorry for being a number dropper).
C++ or JavaScript? I don't feel that question has too much to do with whether you use QtQuick or not. Sure, you can embed some JaveScript in QML code (with limitations), but you can also use C++ in the same code base (just not embedded in the QML). Then there's Python. Both Qt and QtQuick are programming frameworks, and are somewhat language agnostic.
My perspective is that QtQuick is a good, portable way to create your user-interface code. In my current project (a multi-axis industrial servo-control system) I use QML for the user-interface (with a little JavaScript where needed), C++ for the bulk of the higher level processing (like network control and data-streaming), C and assembly language for the lower levels (those routines executed in uC's and DSP's). QML and C++ interface together nicely, in my opinion.
I believe the speaker is getting at the idea that most if not all your business logic should be done using a C++ model back-end. It is possible to do all your logic just in QML with embedded JavaScript however, because JS is an interpreted language its performance at run-time can possibly be less than compiled C++ code(dependent on how well the C++ is written).
Essentially you only want to use JS to manipulate graphical components while using C++ with QObject models to update the QtQuick elements' individual properties.
This is mentioned in the Qt Quick Best Practices wiki,
https://wiki.qt.io/Qt_Quick_Best_Practices

gtkmm for desktop application

Is it a good idea to use gtkmm gui toolkit for some desktop client application ?
Is this toolkit stable and is there enough documentation online ?
I used gtkmm to write professional applications and yes you can use it for real world software development.
But I also used C/GTK+ and C++/Qt and my opinion is that using Gtkmm you have the feeling that the original toolkit was meant to be used in C and the porting to C++ is ok but in many cases you feel that C++ features could have been used better.
For Comparison:
If you have to choose between Gtk and Gtkmm go for Gtkmm even though you might find yourself stuck in some not well documented or supported function. Eventually you always manage to find a solution (you can check the source code) and c++ is way better then c.
If you have to choose between Gtkmm and Qt, go for Qt. There is a HUGE gap between the two. Not only in the toolkit itself but in the documentation and all the other classes that you need when writing an application.
I started two month ago with gtkmm. I actually port a tcl/tk application and it feels very hard for my to get the things run. The only useful documentation I found is the https://developer.gnome.org/gtkmm-tutorial/3.4/
But many things described in the manual are not working! I actually run into trouble while overriding signal handlers which should work but didn't. Maybe you will take a look in gtkmm-list#gnome.org to find out what kind of problems yo will maybe run in :-)
The docs derived from the doxygen input seems useless for me, because the functions are mostly not described and the parameter names or often not very clear to me.
In comparison to tcl/tk the interface looks inconsistent. Sometimes a parameter must be provided by a text, sometimes by a pointer and sometimes by the native value itself. Especially the menus are very "mysterious" with the string based configuration. The need of having parameters as text is very unhandy! You have to convert the parameter with ostrstream into a text and parse the parameters sometimes yourself from text to real values.
I decided to give gtk+ a chance is the existence of the c++ interface. I thought it would be helpful to get the errors in compile time and not while running the app like with tcl/tk. But this is not the always true with gtkmm. With gtkmm you are also able to run into run time errors because all string parameters will be parsed during run time! This makes the things error prone!
Maybe I will start again and give Qt a chance. But a first view on it shows, that this seems not really better :-)
Writing a gui application still is a really annoying job!
gtkmm is a official supported binding of GTK (gtk.org/language-bindings.php).
"inkscape" and "ardour" are notable applications written in gtkmm
The bindings that are official GNOME Bindings follow the GNOME release schedule which guarantees API stability and time-based releases.
If you want to write your Application in C, go with GTK+ (and the GLib).
You can find a link to the documentation at http://www.gtkmm.org/ (https://developer.gnome.org/gtkmm-tutorial/).
With Glade (and ie. PyGTK) you could rapid prototype your application.
Building a GUI with Glade is easy and the resulting UI is a xml file, that is not bound to a programming language.

Is QT the right solution for my cross-platform application?

My App is supposed to run on both Mac and PC. It needs to access the local file system and manipulate it. I also need to be able to resize images and create watermarked images as well as thumbnails. It's important for my user interfaces to look as similar as possible on both platforms.
Therefore I've been looking at QT which seems to be really up to date but I'm not very familiar with C++. I noticed that QT has support for the Webkit engine and wonder if my application UI can be written in HTML and be controlled using C++?
has anyone done this before? Any pros and cons are really appreciated.
Use Qt
Qt has a strong user community and easy-to-use documentation. All of the platform-specific code is packaged up into C++ clases (QImage, QFile, etc.).
Don't Use HTML for a Qt GUI
Caveat: If you plan on using an HTML interface I don't know if Qt is really a good solution. The default UI for Qt is XML-based (at design-time! - at run-time it uses the native platform GUI).
I haven't personally used WebKit to implement any user interfaces with Qt and that is not the intended design. Usually you'll invoke WebKit to display an embedded web page or help file.
Use QML for an HTML-Like Interface in Qt
As pointed out by gvd below, if you want to design your interface using HTML-like technology, then you will want to use QML.
Sources:
http://doc.qt.nokia.com/latest/qimage.html
http://doc.qt.nokia.com/latest/qfile.html
http://doc.qt.nokia.com/latest/qtscript.html
Develop C++ Qt application GUI interfaces in HTML+javascript?
http://doc.qt.nokia.com/4.7-snapshot/qdeclarativeintroduction.html

What is best GUI toolkit to rewrite .NET WPF application to C++?

We have existing WPF application with complicated graphics (rounded edges of the window, speedometer style indicators etc).
Since we rely on .NET our application needs .NET framework. Some users are unwilling to install .NET and we want to provide them with a version that does not need .NET and runs of Windows only (XP,Vista,W7).
Which graphical toolkit we should use to for this scenario?
So far I think Codejock Toolkit Pro is a good adept as we already have GUI in XAML and it could be easier to port GUI to C++.
However, another aspect is download size of the toolkit. We don't want to end up in the situation where toolkit size is so big (e.g. 20-40MB) that's comparable with .NET 4.0 framework size.
I know some of you might think that going back from WPF to C++ is a bad idea, but for our scenario it is absolutely crucial to make user's installation process as easy as possible and .NET framework is a big stumbling block which we are trying to remove.
Sorry I do not have the answer to your question (and I would never ever even dream that I might do such a thing), but I am compelled to tell you as an advice
implementing all the WPF functionality in C++ will take 10-20 times more
installation of a C++ would not be necessarily easier
if you need to make installation easier, use SilverLight
We used QT in one of our projects in past which is Object Oriented and Multi Platform, but QT is mostly like WinForms
As I remember QT keeps UI in xml files too, try to write XSLT from xaml to QT xml. But I don't thik you can do it in complex WPF structures like Triggers or Animation
Have you evaluated QT? Since this relies on XML for UI definition too, it might be easier to port the code to.
You've already gotten a couple of answers recommending Qt -- and I'd agree that's probably your first choice. Note, however, that while Qt does support an XML-based UI description, they seem to be moving away from it toward QML, which is based on JavaScript instead.
Another possibility would be wxWidgets, which also supports an XML-based description of the widgets using XRC.

Prototyping Qt/C++ in Python

I want to write a C++ application with Qt, but build a prototype first using Python and then gradually replace the Python code with C++.
Is this the right approach, and what tools (bindings, binding generators, IDE) should I use?
Ideally, everything should be available in the Ubuntu repositories so I wouldn't have to worry about incompatible or old versions and have everything set up with a simple aptitude install.
Is there any comprehensive documentation about this process or do I have to learn every single component, and if yes, which ones?
Right now I have multiple choices to make:
Qt Creator, because of the nice auto completion and Qt integration.
Eclipse, as it offers support for both C++ and Python.
Eric (haven't used it yet)
Vim
PySide as it's working with CMake and Boost.Python, so theoretically it will make replacing python code easier.
PyQt as it's more widely used (more support) and is available as a Debian package.
Edit: As I will have to deploy the program to various computers, the C++-solution would require 1-5 files (the program and some library files if I'm linking it statically), using Python I'd have to build PyQt/PySide/SIP/whatever on every platform and explain how to install Python and everything else.
I want to write a C++ application with Qt, but build a prototype first using Python and then gradually replace the Python code with C++. Is this the right approach?
That depends on your goals. Having done both, I'd recommend you stay with Python wherever possible and reasonable. Although it takes a bit of discipline, it's very possible to write extremely large applications in Python. But, as you find hotspots and things that can be better handled in C++, you can certainly port relevant parts to C++.
Is there any comprehensive documentation about this process or do I have to learn every single component, and if yes, which ones?
Here's what I'd recommend for the various pieces:
EDITOR/IDE: Use any editor/IDE you're comfortable with, but I'd highly recommend one that supports refactoring. If you're comfortable with Eclipse, use it. If you want to mainly go the C++ route and you're not too familiar with any editors, you might be better off with QtCreator. Eric is an extremely good Python IDE with support for refactoring, unless you're going to be doing lots of C++, take a look at it. Even better, its source code is an example of good PyQt usage and practices.
PROCESS:
The quick summary:
Write your application in Python using PyQt
When identified as hotspots, convert decoupled Python classes to C++
Create bindings for those classes using SIP
Import the newly defined libraries in Python in place of their Python counterparts
Enjoy the speed boost
General details:
Write the application in Python using PyQt. Be careful to keep a good separation of concerns so that when you need to port pieces to C++ they will be separate from their dependencies. When you finally need to port something to C++, write it in C++/Qt and then create bindings for it using SIP. SIP has a good reference manual on the process, and you have all of PyQt as an example.
DEPLOYMENT:
C++ - For many applications the dependencies are sufficiently simple that it's not too difficult to create an installer using a tool like NullSoft's Installer or InnoSetup.
Python/PyQt - PyQt applications are a bit more difficult to install because of the dependency on Python and its dependence on the presence of the Qt libraries. One person documented his efforts on this post at ARSTechnica. py2exe works pretty well on Windows and should work fine. IME, freeze.py, which comes with the Python source, sometimes has problems determining which shared libraries are truly necessary and will sometimes end up creating a binary whose dependencies aren't present. Py2app can be made to work on Mac OS X.
But worse, however, is the PyQt/Qt licensing. If you are developing a commercial application, you need to have a commercial PyQt (and Qt) license and make sure to prevent the users from easily modifying the source or otherwise writing code against the PyQt/Qt API because of licensing restrictions. Because of that, the PyQt author created a tool called VendorId (although it has a Python license). Within VendorId is a tool called SIB that can be used to create an executable which depends only on the Python interpreter. But, if you're going to go this far, you might want to install a custom Python along with your application.
DISCLAIMER: I haven't used PySide at all, so I'm not sure how it compares to PyQt. Also, note the following warning on their website:
PySide is a work in progress and is not yet suited for application development requiring production-level stability.
But, on a good note, they intend, at least for the initial release to "maintain API compatibility with PyQt." So, aside from the C++ bindings, you could easily switch between the two later.
If you are just learning Qt and want to leverage the speed of prototyping that Python gives you, then I would recommend you make a sample project using PyQt. As you said, there is a debian package, so you are just a simple apt-get away from making your first application.
I personally use gVim as my Python/Qt editor, but you can really use any Python-friendly editor without much trouble. I liked WingIDE and they have auto-complete for Qt but once you sip from the vim kool-aid it's hard to switch.
I would say that PySide is 95%+ compatible with PyQt and the LPGL license is nice, but if you are just trying to prototype your first Qt app, then I don't think there is a real reason to use PySide. Although, I do like the PySide docs better, you can also just use them and replace all the library references with PyQt.
Depending on the complexity of the application you are building, it might be better off to just start from scratch with a C++ version than to try to do a bunch SIP refactoring black magic. Once you have a solid grasp of the Qt framework, you should be able to switch between the C++ and Python bindings pretty effortlessly.
I would draw UI mockups before starting to code prototypes. Here are some benefits:
Quicker than coding prototypes as there is no programming involved
Quickly fill widgets, such as tables and trees, with data
Add descriptions and notes to your screens
Easily integrate mockups into specification documents without having to capture screens
Validate UI design concepts before implementing
There are a lot of tools that can help you do that, but if you are going to use Qt, MockupUI may be a good choice as it renders Qt widgets with native styles for Windows 7,8 or 10 which makes your mockup look more realistic.