original:
Http://linux.online.tj.cn/ubb/forum4/html/000065.html
Qt introduction
- One of the QT application development series
Freedom of Freedom, Word November 10, 2000
QT is a cross-platform C graphical user interface library, which produces QT, FrameBuffer QTembedded, fast development tool Qt Designer, International Tools QT LINGUIST, etc. , Also support WinNT / Win2K, WIN95 / 98 platform.
Trolltech was established in 1994, but in 1992, the programmer of establishing Trolltech has begun to design QT, QT's first commercial version launched in 1995 and then the development of Qt is very fast, below QT Some milestones in the history of development:
1996 Oct KDE organizes 1998 APR 05 Trolltech programmers Transplant Netscape5.0 from Motif to QT, 1998 APR 08 KDE Free QT Foundation, 1998 JUL 09 QT 1.40 release 1998 JUL 12 KDE 1.0 release 1999 Mar 04 QPL 1.0 release 1999 Mar 12 QT 1.44 release 1999 JUN 25 QT 2.0 release 1999 Sep 13 KDE 1.1.2 release 2000 Mar 20 embedded QT release 2000 Sep 06 QT 2.2 release 2000 OCT 05 QT 2.2.1 Release 2000 OCT 30 QT / Embedded starts using the GPL Declaration 2000 Sep 04 Qt Free Edition Starts with GPL basically, QT with the MOTIF, OpenWIN, GTK, etc. on the X Window, and the MFC, OWL, VCL, ATL on the Windows platform, and the same type. But Qt has the following advantages:
Excellent cross-platform characteristics:
Qt supports the following operating systems: Microsoft Windows 95/98, Microsoft Windows NT, Linux, Solaris, Sunos, HP-UX, Digital UNIX (OSF / 1, Tru64), Irix, Freebsd, BSD / OS, SCO, AIX, OS390, QNX, etc.
Object-oriented
Qt's good packaging mechanism makes QT's modularity, and it is very useful for users. It is very convenient for users. Qt provides a safe type called Signals / Slots to replace Callback, which makes collaboration between each component very simple.
Rich API
QT includes up to more than 250 C classes, also for template-based Collections, Serialization, File, I / O Device, Directory Management, Date / Time class. Even the processing function of the regular expression.
Support 2D / 3D graphics rendering, support OpenGL
A large number of development documents
XML support but truly enables QT to stand out in the free software boundaries (such as LeSSTIF, GTK, EZWGL, XFORMS, FLTK, etc.) or based on Qt-based heavyweight software KDE. Interestingly, KDE is also a reason for Trolltech to suffer huge pressure. Below we will see how this famous free software hairy - "KDE / Qt .vs. Gnome / gtk" is happening. The Unix graphical interface has always been a MIT's X Window system as a standard, but there are two major genres in commercial applications. A distribution is the Openlook camp led by Sun. The one is the OSF (Open Software Foundation) led by IBM / HP. Motif, after many years of competition, MotiF finally won, becoming the most common interface library, and then compromised a CDE (Common DeskTopenviroment) as a standard graphical interface. However, the price of Motif / Cder is very expensive, and the Microsoft's Windows graphics interface has developed very fast, and the LINUX from the UNIX boundaries also urgently needs a reliable and free graphical interface.
In October 1996, the German Matthias etTrich of the development graphic typography tool LYX launched a KDE program. KDE's full name is Kdesktop Environment, it can be seen that it is for CDE. KDE itself uses a GPL declaration, but KDE is using QT as its underlying library, because QT has been freely released by QT, but QT does not follow GPL, so KDE is attacked by many free software, thinking Using non-free software to develop violation of GPL, the GNU's fanatic belief is divided into two ways. All the way is to make Harmonny, try to override a set of replacement compatible with QT, and another 26-year-old Mexican programmer Miguel DE ICAZA Leaders re-developed a set of GNOME (GNU Network Object Environment) to replace KDE.
Due to the copyright of the Linux world, Redhat did not like the copyright of KDE / QT, and Redhat even sent several full-time programmers to join GNOME for development, so a holy war similar to Motif VS Openlook was like this. Trolltech has changed the copyright of QT several times in the KDE, from the establishment of the KDE Free QT Foundation to adopt QPL, which is a cost machine, but GTK used by GNOME is completely GPL, so gnome has a certain advantage in this respect. Plus QT / KDE is developed with C , the gate threshold is relatively high, and GTK / GNOME uses C, so GNOME has attracted more free software developers, but KDE will take a step after all, and KDE1.1.2 is very stable. At the time, the system stability of GNOME1.0 launched, and some even laughed, gnome1.0 did not have KDE 1.0 Alpha stability. But gnome has rapidly developed, and there is a momentum of the head. At that time, the developers of both sides were fried in the network, even Linux's father Linus just said, I like to use KDE.
The war has arrived in the third year, that is, in 2000, it can be said that it is a stricken mutation. A major event has happened: first is a group of engineers from Apple set up a company called Eazel design interface, then A group of GNOME programmers set up a Helix Code to provide commercial support for GNOME, and everyone expecting Long-term KDE 2.0 finally released, which is probably one of the most large free software, except KDE itself, including Koffice Kit , And integrated development environment KDevelop, etc. A large number of software, its main software KounQueror is also the first browser that can be equivalent to Microsoft Internet Exploer. A group of companies such as Sun, Redhat, Eazel, Helix Code set up a GNOME Foundation, and Sun also announced that the heavyweight office software Star Office is integrated with GNOME. Trolltech naturally can't sit still, on October 4 this year. Change the QT's Free Edition into a GPL Declaration, completely solved the copyright issue of KDE, and introduced embedded QT, giving a powerful root of Gnome camp. So far, this war is still going, I believe we can't see the results soon. Generally speaking, the company currently attracting more companies, but the efficiency and quality of KDE / QT are higher than GNOME, and in the Office / embedded environment, take a step in a certain period of time.
So, how do you choose in QT / GTK? Generally, if the user uses C , the stability of the library is relatively high, and the robustness is relatively high, and if you want to develop, then use QT is better. The choice, but it is worth noting that although QT's FreeEeeee uses a GPL Declaration, if you develop Qt software on Windows or commercial software on UNIX, you still need to pay copyright costs to Trolltech.
Some programming techniques about Qt will be introduced in future articles.
Reference:
QT online resources lists QT, GNOME-related important resources: QT Download Helixcode URL EAZEL
