I am contemplating designing a framework to allow for one C++ code base to become a desktop application and a web app for most major platforms (Mac OS, Windows, Linux, and possibly Android). I have decided Qt would be best for desktop builds, however I am conflicted between Google Native Client and Wt for the Web App part.
Wt code may be more easily compatible with the Qt code, however I heard Wt is actually AJAX output so I do not know how much this will impact performance (I plan to develop a game engine with this so I need performance).
On the other hand NaCl, is more, well... native. But it seems to be a mess, especially with the JS integration, I just want to write in C++ and be done with it. Additionally I don't know how compatible it would be with Qt.
I have been researching this for weeks and I do not know much about either. So it really boils down to:
A: Could I literally (or pretty much) replace all the W's in the front of the names of all Wt objects with Q's and have it be Qt compatible code?
B: Is Wt native at all, and how fast does it execute at run time (I cant seem to find an answer to this)?
It would be possible to run Wt as a NaCL application as well, in fact, that would combine the best of both worlds. Wt itself (and its dependencies) build fine with the NaCL toolchain, it's only a connector library that is missing currently. There was an opening for a GSOC project to implement last year, but it didn't happen.
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I am a C++ programmer, but for some reason, I have to develop a website by myself(My own commercial project). I don't want to take a lot of time to study JavaScript and something else. It is possible to just use QT and WebAssembly (instead of HTML + CSS + JavaScript) to develop a front-end web?
Yes, it's absolutely possible and I'm currently doing it for a project but you should do it carefully based on the project requirements, running environment and your own backgrounds.
Here are some problems you may encounter:
The output .wasm file may get too large. Generally, it won't be suitable for public domain applications.
In low-end devices, maybe you find it laggy if you don't do enough code level optimizations.
Threads are not officially supported yet (as of Dec. 2019) by major browsers but tech-preview is available. This is not a real big problem as it would be a standard feature soon.
Native virtual keyboard won't work on mobile devices but the work is in progress.
These were my own major problems with Qt for WebAssembly.
Despite this, I find it much more flexible than HTML+CSS. QML is really a nice language for UI development. Creating animated UIs is quite easy and straight-forward.
You can also use many JavaScript libraries in your QML code like Lodash and Moment or any other js library that does not refer or manipulate window DOM.
Yes, it is possible. But you should do not do it if only reason is reject for learning new technologies.
For now (I'am writing this answer when Qt 5.14 is present) Qt for webassembly is deployed as official platform. Unfortunately it is young platform support with a lot of problems and possible future changes. Qt team do really good job so next version will be better. 5.14 is much better than 5.13 in webassembly context but still need fixes.
You should know Qt for webassembly will support only a few Qt modules, excluding widget. Yes, you can only use QML for GUI.
Qt for webassembly was created for the purpose of port one code base in other platform (it it generally Qt develop way, please see Qt for MCU). With other technologies in this stack like QRemoteObject is very interesting technologies. It was not created for websites in normal network. Main Qt for webassembly target are internal network systems and remote control of devices. Pay attention about this.
Unfortunately, not all browser will support webassembly right. Please see Qt for weassembly support notes.
Additional, in Qt you can't find build-in rest-API handle or other standard web technologies to integrate with your existing backed.
We are trying to create an Application for all mobile platforms (Android, iPhone, Windows phone). We will build the User Interface using the native development languanges for each platform (Java, Objective C, C#). For the intermediate layers (DataAccess Layer and Business Logic Layer) we plan to use C++ for all platforms.
We are going to use libraries like Curl, sqlite3, libzib. So I think a good solution would be to create two seperate C++ projects (DataAccess and Business Logic) and make references to those libraries we need. First we are going to start with Android, so I will include those two projects as prebuilt static libraries using Android NDK and in the jni folder I will add some methods that they will communicate between UI and Business Logic. Later we will do the same for the other two platforms. Since I am very new to C++ I would like to make the following questions:
Do you think that this theoretically will work?
What problems are we going to face (e.g debugging, using Curl in different operating systems)?
Are there any open source mobile projects using the same approach?
Do you think that this theoretically will work?
Yes, I've written and app for Android and iOS that uses a data access layer written in C++ on both platforms. I wrote the Android edition and a colleague wrote the iOS edition. It is not open source, so I can't show you the code.
What problems are we going to face (e.g debugging, using Curl in different operating systems)?
Debugging the shared C++ code can be a pain in the ass on Android. I've never gotten the debugger for work on Windows. I normally resort to careful reading of my code and printing messages to LogCat if it is not something I can reproduce and debug on iOS. Normally this only affects the JNI layer that links the C++ business logic and the native UI code.
You'll probably have to build 3rd party libraries separately for platform. Curl has instructions for building it for each platform so that shouldn't be much trouble.
Apart from learning JNI, the biggest problem I had was that the app had to look the same (or very similar) on each platform. I'd recommend looking into Qt Mobile Edition as
πάντα ῥεῖ suggested, however it doesn't currently support Windows phone. Still, you would be able to write one UI for two of your three platforms at least - and your shared business code would still be reusable. We are in the process of starting a second app and Qt is definitely looking like the best option for us. I don't think we'd want to repeat the experience of trying to provide the same functionality on two platforms using very different APIs.
Are there any open source mobile projects using the same approach?
I'm not aware of any off-hand, but I'm sure you can Google it.
I've already written some backend *.dll files that I intend to use in a project. I need to visualize a simulation of the code, for which I intend to use charts and graphs from Chart.JS, by using it along with TideSDK for a desktop application.
I have no clue on how to call the C libraries via JS though. And I want to avoid creating wrapper classes in Python and going through that circuitous route. Any other options? Or are there any alternatives when trying to create an HTML/CSS/JS desktop application connected to a backend C/C++ library? Will AppJS make things easier?
TideSDK is capable of extension with modules that can be compiled and included in its runtime. It was written to be extended but I would recommend waiting for TideKit. TideSDK is a bit old and setting up a toolchain could be problematic at this point.
We've been investing in a broader vision with TideKit that is getting ready for release. You will be able to extend it with native modules and you won't need to wait too much longer to see what we've been up to. http://youtu.be/aE7gN-d0GhUthat
If you have started anything with TideSDK, you will be able to migrate your code easily to TideKit. The ability to work with with native or JavaScript modularity, and to develop for all screens from a single project code base is where all our efforts have been going.
Note that AppJS was discontinued earlier this year. An alternative is writing C extensions in node through node-webkit. Note that if you are going cross platform on this and you needed OSX as well, you cannot achieve Apple AppStore compliance with node-webkit due to private APIs as a result of its port of webkit.
I'm interested in the following features:
Writing an app for Android Market that is written completely in C++ (a port of existing product actually).
Use fast screen-buffer pixel pushing (or rather using OpenGL ES for this).
Grab user input and direct it to C++ code.
Is it legal to write such an app for Market? Is Market policy somehow strict to such things?
As of NDK r5 with Android 2.3 (Gingerbread) this is possible, although I assume only devices to support natives apps must have Gingerbread on them.
From the native-activity sample:
The Android SDK provides a helper class, NativeActivity, that allows you to write a completely
native activity. With a native activity, it is possible to write a completely native application.
NativeActivity handles the communication between the Android framework and your
native code, so you do not have to subclass it or call its methods. All you need to do is declare
your application to be native in your AndroidManifest.xml file and begin creating your native
application.
It is really not my cup of tea but there is something called Android NDK (Native Development Kit) to use if you want to write your program in C. Not sure how the C++ compiler support is though.
As far as I know your app can be almost 100% native code but keep in mind that by walking that way you will probably have a hard time supporting the different CPUs out there in Android hardware. If you need to bootstrap the native code so that it is started from java it is probably not a very big problem for you.
I found a few different tutorials when googling for "Android NDK". This one is a very minimalistic Hello World. Obviously you want something much more than a library that returns a string to java but it is a good first start and you will probably have to do all of the things described. Do a search using NDK and Android as keywords and you get a good selection. I see no reason to list them here as such lists tends to be outdated and broken within a year or so.
I guess the official Android Developer site from Google will stay put and be updated on new releases of the platform, it has a link to the current NDK.
With Gingerbread (Android 2.3) it looks like you can build your entire app in C++.
cf:
http://phandroid.com/2011/01/11/android-developers-blog-awesome-ndk-leads-to-awesome-apps/
"
With the latest version of the NDK, r5, many big improvements have been made to coincide with the release of Gingerbread. The most major is the ability to code a native application for Android 2.3 entirely in C++. This means even programmers and developers with no Java knowledge won’t have to implement a single line of that code..."
Can't vouch for the veracity of this blogger, however, from what I have read, it appears you can do this
There is no 100% native solution but what I think you are looking for is the Android NDK (Native Development Kit)
From their site "Please note that the NDK does not enable you to develop native-only applications. Android's primary runtime remains the Dalvik virtual machine."
I believe it lets you make calls to your own native code from an Android application
I have personally never used it for my games, but I am sure it would help on a lot of things (like being able to manage my own memory and not have "lag" do to the garbage collector)
conversations in this thread can help you.
http://groups.google.com/group/android-ndk/browse_thread/thread/50362904ae0574cf
essence is,
It is possible to make Native only apps and Android Market doesn't restrict you either.
But with limited support for native development, there is high chance of using some of the non standard functionality which might break in future releases.
http://developer.android.com/guide/basics/what-is-android.html
"The Android SDK provides the tools and APIs necessary to begin developing applications on the Android platform using the Java programming language."
http://arstechnica.com/open-source/news/2009/06/android-goes-beyond-java-gains-native-cc-dev-kit.ars
In general, you don't. There is some limited C++ support through JNI, but it is mostly intended to supplement Java code, not replace it. There's no framework/API support (AFAIK) for C++, so doing this isn't really an option.
Is Qt an interesting platform for business apps development, outside of Nokia phones ?
Why ? Strong points ?
Thanks
I like Qt because:
Very well-designed framework, e.g. signal-slot, model-view, graphics view/scene/item/proxy, painter/paint device/paint engine..., too many to be listed here!
Excellent documentation!
Cross platform language/API, as well as tools like UI designer, creator, and so on.
Rich features, e.g. graphics framework, network library, database engine, and so on.
Active community, and active development.
There should be more. If you have ever used it, you'll find it's easy to build your framework upon Qt.
I didn't have any complain to Qt. If I have to say at least one disadvantage here, "convention". You must adopt the convention of Qt, e.g. You have to use moc to make the meta object of your objects, and it's easier for developers to use Qt's vector, list, auto_ptr than STL, tr1. But I never found any issue caused by that. On the contrary, it works very well.
In my opinion, Qt is the state-of-the-art C++ framework in this modern world!
P.S. There are a lot of commercial applications built on Qt. You can find it under Qt's official website. But I'd like add one more here: Perforce, one of the top commercial source code management tools, built its client tool on Qt for Windows/Linux/Mac.
yes it is .. just look at kde apps :)
or see more applications made by qt
and it has alot of bindings in many languages
Documentation
cross-Platform IDE
further reading
may be this is not so related to the question ... but my first deal with qt was just great starting from their well organized Documentation to their great widgets
the GraphicsView is just ammazing ! :)
It's about the only current/modern C++ gui library on Windows.
MFC is so old you have to write comments in Latin
WTL would be nice if they had finished it before abandoning it.
Winforms/WPF + managed C++/CLR - all the fun of several incompatible new technologies at once.
Bad points:
To fit on lots of platforms they have invented their own solutions to things that are now in the STL/Boost
The signal/slot mechanism - tricky to debug and silently fails (with no error) with simple typos.
Although everything is possible it's sometimes a lot of effort to do simple things (they do love MVC) compared to Winforms.
Qt is simple
Qt is powerful
Qt is NATIVELY-CROSS-PLATFORM
Qt is REALLY-CROSS-PLATFORM
Qt is comprehensive (but the Media side of it still needs to grow)
Qt doesn't require Garbage Collection, but it embeds a GREAT model of memory management that makes you forget about memory deallocation
Qt is solid
Qt is modern
Qt proposes some new paradigm of programming that are really good (Signals-Slots)
Qt runs a lot of VERY successful software: (Skype, Google Earth...)
Are those points strong enough?
Maybe you have heard about Google Earth which happens to be programmed in Qt too.
That aside, I like Qt for my in-house development because it
is very well supported and documented,
allows me to write simple and decent-looking apps that are
works cross-platform for Windows and Linux with little effort, and
contains nice to have components for database access, regexps, guis, xml, ...
I also use the Qwt widgets for easy real-time plotting on top of Qt.
I really dont understand whats the point in underestimating tools/frameworks which makes things easy for programmers. Qt is too good for GUI development, I would say its much better than any current existing crossplatform app development suite.
So many advantages, I have been using it for more than three years now for a product to be deployed in Linux/Win environments. The app is thread intensive and initially we had a tough time using pthreads and its conterpart for windows. Then we switched to Qt(and QThreads eventually) and things were a breeze...
Backed by active development, a highly helpful and supportive community along with excellent documentation, training, certification programs, videos, forums... its easy, fast and effective to develop in Qt. You should see the video which they create a web browser in just five mins!
Its really 'cross platform', and it doesnt have a software wrapper(like Java does) to enable this which makes it faster. Cmon, we all know java apps have buttons which takes a second to respond to even a simple 'click'.
I hope Qt will someday do a take on Java. :D
after all, 350000 developers cant be wrong when they chose Qt.
Pixar uses Qt (or at least, used, as of 2005) internally for certain parts of their tool suite (called "Marionette" in the marketing) collectively called Menv, ("men-vee" for Modelling ENVironment)---at least for their lighting sub-tool Lumos.