Qt 5 Beta发布

On 2012年08月31日, in soft, by netoearth

The Qt 5 Beta is now available as the first major release under the new Qt Project umbrella. A big thank you goes out to all who contributed to this milestone. With this Qt 5 beta release, I would also like to invite everybody interested to go, try, and experience this next major version of Qt. Your feedback now will be very important in making the final release of Qt 5.0 as good as possible.

It’s now 15 months since we announced the start of Qt 5 development, and I am really happy to see what has been achieved during this time. All of the major architectural changes that we planned for have been implemented. At the same time, the community around Qt and qt-project.org has seen a nice and healthy growth.

Qt 5 will make it easier and faster to create:

  • Smooth, accelerated graphics performance with limited resources. Qt 5 makes better use of the GPU to deliver better performance on inexpensive hardware. For example, using Qt 5 you can achieve 60 fps performance on a $35 single-board computer like Raspberry Pi. – See the Qt on Pi project for more info.
  • Advanced UIs and applications written in QML and JavaScript. See the Qt Media Hub as an example
  • Powerful apps connected to the web

High-performance Apps and UIs

Qt 5 addresses two core challenges developers face when creating high-performance apps and UIs:

  1. Better tools to design the UIs and
  2. Better rendering performance to execute your vision.

The new extensions and APIs to the QML language make it easier to create rich and fluid apps and UIs for touch screen devices in addition to supporting keyboard input methods. Qt 5′s updated WebKit and Qt Quick modules support out-of-the-box touch interaction for smooth user experiences.

The new graphics stack sports an all-new rendering pipeline using an OpenGL based scene graph that is fully optimized for Qt Quick. This makes it trivial to integrate OpenGL-based content, such as shader effects or particles. Text rendering is also fully hardware accelerated, giving you faster graphics and lower power consumption. As a result, Qt 5 delivers the same 60 fps smoothness seen on high-end smartphones even when executed on inexpensive hardware like the Raspberry Pi.

Providing Source Compatibility and Continuity – Porting and QWidgets

A lot of effort has gone into making the transition of your code base and skill set from Qt 4 to Qt 5 as easy as possible and to keep as much source compatibility with Qt 4.x as we can. As an example we currently have Qt Creator compiling and running against Qt 4.x and Qt 5 using the same code base.

You can find links to detailed porting instructions on the Qt 5 beta page or look at some examples of KDAB’s porting efforts.

Updating your code base is primarily a process of updating your projects’ .pro files, to change header file includes and add used modules. Qt 5 provides a script that facilitates this task. In addition, code that integrates with native windowing system functionality of the underlying platform will need some adjustments.

While new UI designs benefit from the updated QML for mobile and embedded applications, it is also important to notice that existing widget-based designs remain viable. Widget-related APIs continue; QWidget and all derived classes are a core part of Qt 5 on the Desktop – and will remain so.

New APIs and modules

In addition to the changes to the internal architecture, a lot of new APIs have also found their way into Qt 5. Many new classes appeared in QtCore, providing support for JSON, mimetype recognition, standard paths and many other things.

The OpenGL support is now an integral part of QtGui and has received some nice improvements. QWindow provides a better abstraction for top-level windows then the old QWidget.

A couple of new modules have been added to the scope of Qt 5. In particular, the differentiation between Qt and Qt Mobility that existed in Qt 4.x has been removed. Instead we now have a more modular structure and each module (a shared library or QML import) is now classified as either being part of the Qt Essentials or an add-on.

This new structure will make it easier in the future to integrate modules providing new functionality into the Qt Product offering, and allow for example KDE to provide their frameworks as add-ons to Qt.

Greater opportunity

In addition to delivering the best development environment possible, it is important that Qt increases your opportunity to get your projects in front of a bigger audience.

With Qt 5, support for multiple operating systems continues. The QPA abstraction layer makes the task of porting to new platforms easier and more seamless then ever before. We are already seeing a lot of work going into Qt 5 to implement a full port to QNX and Blackberry 10. Digia has already announced their plans to port Qt 5 to Android and iOS.

In addition, a lot of effort and contributions have gone into especially improving the use case for embedded developments on Linux. This helped the strong growth/up-take we witnessed within Qt for Automotive, IPTV/ STB and other IP comms manufacturers for current and next gen infotainment systems.
Discussions regarding what additional improvements Qt 5.1 will bring to the desktop use case and how quickly i.e. we can integrate Qt desktop components are ongoing and were also part of the sessions that ran during 3 days when close to 200 contributors attended the Qt Contributor Summit in Berlin during the end of June.

Known issues

While we are happy with the current state of the beta in most places, there are a few known issues that you might want to check out from ourKnown-Issues page. Most notably, you will need decent OpenGL drivers on Windows for Qt Quick to work, and there are issues remaining with Qt Multimedia on platforms other than Linux.

We expect these issues to get resolved for the Qt 5.0 final, where we will by default use ANGLE to layer OpenGL on top of DirectX (the option to use the native OpenGL support on Windows remains of course) and work on the remaining Multimedia issues.


One thing that is becoming very visible now is how much the start of the Qt Project and move to Open Governance helped in improving Qt. Over the last year, we have managed to create a very active and passionate community of developers around Qt, and many of the improvements we are now seeing in Qt 5 would not have been possible without all this efforts.

As an example, I’d like to mention all the improvements that flowed from the KDE libraries back into Qt 5. These will actually make it possible to have a more modular approach for KDE applications and fully remove the differentiation between a KDE and a Qt app

I am very proud of what has been achieved with Qt 5. A big thank you goes to everybody who has in some way contributed to bringing Qt 5 to where it is now. Let’s also take a bit of time to celebrate all the hard work that has gone into this release, as the first major beta released under the new Qt Project umbrella.

Lars Knoll

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