Does Qt need a modern C++ GUI API?
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I have never used QML and I do not have plans to use it. IMHO it's interesting for beginners who are doing simple projects. But, at least it will be a easy door for beginners to enter into Qt. This door has benefits and the costs for this benefits should be balanced. That's the fact.
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You loose a lot by having this attitude ;) QML is a really nice tool, it's not a monster and is unlikely to eat you.
Anyway, you can do as you wish, of course. I mean to hint at the fact that perception about QML tends to change rapidly once one actually tries it, or at it has in my case.
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@sierdzio : I'm sure that I loose a lot by having this attitude. I did not mean that I'm disagree with existence of QML or using it. It does not fit with projects I'm working on or I have worked on. My wings are much more powerful with C++ API at this time. This is about how you think. As I said, many people are happy with QML and this is enough to let it be there and improve it. This is a dynamic world.
I will try using it as you said it may change my opinion about it. -
Yeah I kind of suspected that this is what you mean, and I've meant no harm :)
Just couldn't stop myself, sorry.
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[quote author="cincirin" date="1334815916"]I believe Apple Animation Framework is what Qt C++ GUI have to follow[/quote]
That could have been my words. Like Apple or not but the iOS GUI is the best prove of a smooth working UI that can be coded natively. Besides that it would bring native looking buttons etc. (in the world of the Cupertino fruit there is something like a native looking widget)
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[quote author="hardcodes.de" date="1353420894"]
[quote author="cincirin" date="1334815916"]I believe Apple Animation Framework is what Qt C++ GUI have to follow[/quote]That could have been my words. Like Apple or not but the iOS GUI is the best prove of a smooth working UI that can be coded natively. Besides that it would bring native looking buttons etc. (in the world of the Cupertino fruit there is something like a native looking widget)
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I agree with these. For ios development we have the ability to visually design the UIs and access them in the application and apply any effects or animation. A declarative framework is not needed here. I feel GUI should always be done using a visual designer unless you need your GUI to be dynamically generated based on some application parameters. The underlying code generated can be xml, qml, c++ or anything. Both ios and Android uses xml. But ios hides this behind the interface builder. Hand creating a GUI is tedious whether you are using Qml or c++. The ios approach seems the best. We have a lot of trouble writing complex GUI for Android since we have to hand create all the needed xml. Same is the case with Qml. A visual designer for Qml together with the ability to access these components from c++ is the best approach. In my experience, Qml is tough for the html people and something alien for the c++ folks.
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[quote author="Jayakrishnan.M" date="1353471883"]A visual designer for Qml together with the ability to access these components from c++ is the best approach.[/quote]"Using the QtQuick Designer":http://doc.qt.digia.com/qtcreator/creator-using-qt-quick-designer.html
"Using QML in C++ Applications":http://doc.qt.digia.com/qt/qtbinding.html
[quote author="sierdzio" date="1353412782"]I mean to hint at the fact that perception about QML tends to change rapidly once one actually tries it...[/quote] -
I recently started using QML, I'm really newbie. I like it but I also agree that it's much more powerfull to use the designer. The problem it that designer seems to be somewhat broken.
Another problem to me it we have Meego components, symbian components, (and also desktop components ???), but if I choose a new general QML project in QtCreator, the available components don't even have a button, I have to do it myself. Souldn't not be avalible many more cross plataform components (code once deploy everywhere) ? Am I missing something ? -
[quote author="john_god" date="1353499489"]I recently started using QML, I'm really newbie. I like it but I also agree that it's much more powerfull to use the designer. The problem it that designer seems to be somewhat broken.
Another problem to me it we have Meego components, symbian components, (and also desktop components ???), but if I choose a new general QML project in QtCreator, the available components don't even have a button, I have to do it myself. Souldn't not be avalible many more cross plataform components (code once deploy everywhere) ? Am I missing something ?[/quote]You are right, of course. Those elements are missing due to many reasons, mostly due to the long and dramatic death of Nokia support. Now Digia has a huge amount of work on their hands, and a lot of it is more important than components at the moment. I don't know where it will go in the future.
Maybe setting up a new playground project with the aim of adding new cross platform components is the way to go. maybe waiting for desktop components maturity is better... I don't know.
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Another issue to me is the documentation. I already found some good links, but I miss a good QML book. Until now it was perhaps to early, but in the following months, with the final release of Qt5 and QtQuick 2, I think it's time for a book. I even filled a request to packet publish, since those guys are open to sugestions.
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You only find the designed better because you are new, I can assure you, in time you will really get to prefer typing and leave the visual workflow for where it belongs - Photoshop.
The lack of in depth educational materials on QML is a big concern, like 90% of the stuff that is already available boils down to putting together something simple to demonstrate the eye candy features of QtQuick. And even thou every tool of QML is being explained, there is a HUGE gap between knowing what tools are used for and actually putting together something complex and functional with those tools.
Unfortunately, the biggest flaw of QML for me will not go away ever - with the risk of repeating myself, QML is great for quickly assembling existing components into an application, but if your applications depend entirely on custom and unique components, the interfacing to QML becomes a tedious and pointless endeavor. In most of the cases the interfacing components to QML in order to use its GUI features takes up more effort than implementing similar GUI features with QtGui and OpenGL on hand, which is the reason for this discussion.
Unfortunately, neither Nokia, nor Digia seem to have respect for the opinions of the people who voted here. That is the reason I migrated most of my work away from Qt, so the last few months I bothered to learn a few JS frameworks in depth, and I dare say QML comes nowhere near the flexibility and dynamics of the HTML/JS stack. Surely, QML is much cleaner, but offers poor separation and only a fraction of the functionality. It is ironic how the main bullet point of QML is "dynamic" GUI when in reality QML is practically static compared to using something like jQuery, which allows to build UI in a procedural and imperative way, which is IMMENSELY more flexible than having a static mark up. I often find myself starting off with practically no HTML markup, just a div to which I can attach whatever content I want dynamically, with whatever styling or animation.
And while flexible and dynamic, HTML/JS comes short of all the stuff I need, for which I am sticking to Qt with the good old QtGui, since essentially all the scenarios HTML comes short are also the scenarios where QML is useless. Hopefully we will at least see Android and iOS support soon which will surely breathe some life into Qt.
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my opinion , every thing z possible with Qt c++
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Ironically, Digia pledged to support Win8 and iOS while at the same time the first one lacks openGL in metro mode, the second one prohibits V8 from running. And while the Win8 dilemma can be solved by adding even more bloat and dependency by using ANGLE to translate openGL calls into Direct3D, it is obvious that forcing Qt to lean on QML spells more and more trouble, and even worse - exhausting to much developer efforts...
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[quote author="utcenter" date="1355679123"]Ironically, Digia pledged to support Win8 and iOS while at the same time the first one lacks openGL in metro mode, the second one prohibits V8 from running. And while the Win8 dilemma can be solved by adding even more bloat and dependency by using ANGLE to translate openGL calls into Direct3D, it is obvious that forcing Qt to lean on QML spells more and more trouble, and even worse - exhausting to much developer efforts...[/quote]
Both problems you have listed are already worked upon. ANGLE is default backend on Windows since Qt5 beta1. V8 problem is addressed by v4mv that is under development currently.
Besides, QtWidgets are now back on track with official maintainer.
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[quote author="sierdzio" date="1355691692"]
Besides, QtWidgets are now back on track with official maintainer.[/quote]Back on track? Which track? Going where exactly? Oblivion?
Maintenance of QtWidgets doesn't change the fact it is morally and technically outdated and no longer relevant.BTW, there is really no need to quote the entire post you are replying to, considering it is the previous one. But then again, if you were that concerned with abstract aesthetics, you wouldn't be such a QML cheerleader ;)
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V8 "does work":http://lists.qt-project.org/pipermail/development/2012-December/008718.html on iOS.
What has the OpenGL requirement of the scenegraph to do with QML? (Nothing.)
How would a native, non-QML interface change that requirement? (It wouldn't.)Why is it Digias or the Qt Projects fault that Microsoft has made the deliberate choice to leave the industry standard for hardware acceleration out? (It isn't.)
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Why you ask me questions and then you answer instead of me? And no, I won't answer for you, I am not all that manipulative ;)
Care to point out where exactly did I state that V8 can't work on iOS? IIRC I used the term "prohibit"... Sure, you can jailbreak, but then your application no longer classifies as "legit" in the eyes of Apple. Also, last time I checked, jailbreaking voids product warranty. Apple don't want any execution engines on their platform for security purposes, and a NATIVE API could have plaid a wonderful role here, because it would compile to platform binary, which Apple don't mind being executed on their platforms.
bq. What has the OpenGL requirement of the scenegraph to do with QML?(Nothing.)
QML is an exclusive frontend to using QtQuick2, which is OpenGL dependent. The relation between OpenGL requirements and QML is obvious enough for a blind man to see!
bq. How would a native, non-QML interface change that requirement? (It wouldn’t.)
It depends a lot, a more flexible API could just as well include a fallback for rendering in software, which is not that much of an issue on powerful desktops. This way the same code would be able to run optimally depending on the capabilities of any particular platform.
bq.
Why is it Digias or the Qt Projects fault that Microsoft has made the deliberate choice to leave the industry standard for hardware acceleration out? (It isn’t.)No one argues that MS sucks. The whole point of this "discussion" is to prevent Qt from behaving in a similar manner. Neither Nokia, nor Digia is to blame for the decision of MS to abandon a portable industry standard in favor of their own proprietary technology, but Nokia and Digia are to blame for abandoning another portable industry standard in favor of their own proprietary technology (got to love the hypocrisy of this), I mean of course scrapping a public C++ API in favor of an exclusive QML one. And while MS surely has the downside when it comes to portability, at least its proprietary technology is more capable, more feature rich and offers public native APIs.
See now Lucas - reality extends far beyond your personal conceptual limitations. For some reason you seem to have a huge problem abstracting from your bias and perceiving the matter objectively.
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[quote author="utcenter" date="1355835060"]Sure, you can jailbreak, but then your application no longer classifies as "legit" in the eyes of Apple. Also, last time I checked, jailbreaking voids product warranty.[/quote]V8 on iOS does neither require a jailbreak in principle, nor does it violate the App Store Terms and Conditions.
The jailbreak is currently required because the used RWX memory allocation scheme is not supported on iOS, but the replacement RW/RX is, which also abolishes the jailbreak requirement.
Apple further on does not prohibit execution engines like V8. The only requirement is that if the origin of the to-executed code is the internet the code has to be interpreted using Apples own execution engine. This does not affect local code and it does not affect QML applications.
[quote author="utcenter" date="1355835060"]QML is an exclusive frontend to using QtQuick2, which is OpenGL dependent. The relation between OpenGL requirements and QML is obvious enough for a blind man to see![/quote]Again, OpenGL is a requirement of the scenegraph, not QML.
A car requires fuel. A car is controlled using a steering wheel. So a steering wheel requires fuel?
QtQuick without QML will still depend on OpenGL. A fully native C++ interface will still depend on OpenGL.
The principal reason for the performance advantage of QtQuick over QPainter and the Graphics View Framework is the state-based, hardware-accelerated OpenGL-based drawing model, called the scenegraph, which is an absolute technical requirement of graphics hardware.
Qt already offers an imperative software- (QPainter) and hardware- (Graphics View Framework) rasterizer. There is no point in creating another.
In addition, the scenegraph requires OpenGL, not hardware-acceleration. It works with any software rasterizer like llvm-pipe in case there is no or limited hardware-acceleration available.
But feel free to share your vision of a hardware-accelerated, platform-independent, high-performance drawing backend (which is obviously not QPainter nor The Graphics View Framwork).
I would love to see my personal conceptual limitations extended.
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So is there any other API to use the scenegraph in Qt other than QtQuick2, which depends on OpenGL and is exclusive to QML? No? thought so...
bq. What has the OpenGL requirement of the scenegraph to do with QML?(Nothing.)
Leaving QML to be the sole actively developed GUI API mandates the OpenGL requirement. Please don't tell me you still fail to see what is obvious and quite simple. QML is being made a requirement, QML requires QtQuick2, QtQuick2 requires the scenegraph, the scenegraph requires OpenGL. I think about 2 working brain cells outta be enough to figure out how the dependency propagates.
My idea was of implementing a low level graphics API that is backward compatible with a software rasterizer, while stile being able to make use of OpenGL hardware when present. This API itself can be ported directly to DirectX as well, making the entire process transparent, without the need of translators and emulators. QPainter already supports hardware accelerated OpenGL drawing and caching, and the performance is as good as that of QtQuick2, it is just that the process is tedious since a lot of the stuff done for you in QtQuick you have to do manually. All this threat is asking for is a native API that handles all that stuff without forcing QML.
No one can force the expansion of your horizon against your own unwillingness to do so.
