What is the difference between Linux GTK, KDE, GNOME, XWindows graphics interface

Linux inherits UNIX's design ideas with the network as the core. It is a multi -user network operating system with stable performance. The Linux graphics interface is the visualization and implementation of many applications. This article mainly introduces GTK, KDE, GNOME, XWindows graphics interface. Friends who need it can refer to

The implementation of the Linux graphics interface is only an application implementation in Linux
graphics interface (GUI) is not part of Linux. Linux is just an operating system based on command lines. The relationship between Linux and XFree is equivalent to the DOS and Windows of the year. 3.0 Like, Windows 3.0 is not an independent operating system. It is just the expansion of DOS. It is an application -level (GUI) system under DOS, not an independent operating system. Similarly, XFree is just an application under Linux, not a part of the system, but the presence of X can facilitate users to use the computer. The versions of Windows 95 and later are different. Their graphic interface is part of the operating system. The graphic interface is implemented in the system kernel. Without the graphical interface Windows The interface is linux or Linux, and many web servers installed with Linux do not install the X server at all. This is also one of the important differences between Windows and Linux.
2. X. X is the protocol, not a specific software
x is a protocol, just like the HTTP protocol and IP protocol. Because the input device and the display device are not the same device, and they need to cooperate with each other to display the screen, so an interactive protocol is required to establish their direct communication bridge.
The X protocol mainly composed of the X application and X server, such as: I need to draw a circle, the X application tells what color of the x server is used in the screen, and the specific "painting" Actions, such as how this circle generates, what graphics driver is used to command the graphics card completion, etc. It is done by the X server.
X server is also responsible for capturing the movements of the keyboard and mouse. The left button of the mouse was pressed, and he told the X application: Mr. Dear app, I found that the mouse was pressed, do you have any instructions? If you draw a square on the screen, the X application said to the X server: Please draw another square, of course, he will tell the server where the color is to draw a square, but you do n’t care about how to draw — that ’s that is it. The server.
three, X and XFree86's relationship
has a protocol, which requires specific software to implement this agreement. As we have traffic regulations, we need traffic police to maintain traffic order in accordance with regulations. XFREE86 is such a "traffic police" that implements the agreement in accordance with the regulations. Regulations, such as traffic associates to implement traffic regulations, when necessary, the police can also intervene. Of course, they all need to understand traffic regulations, that is, they must understand the agreement. XFREE86 is just a free X server software that implements the X protocol. Motif is often used in business, and there are Xorg now. There are still many small X server software written by enthusiasts. You can even run the X server on Windows, so you can run a X application on the Linux system and then How amazing is it on another Windows system! You can use Google to find such an X server software, but the most commonly used on Linux is XFREE86 (the current Linux distribution is used in xorg) By the way, Apple computer The graphic interface is also used in the X protocol, and it is considered to be the best X protocol graphics interface, and his implementation of the X protocol is in the system kernel, so the performance is significantly better. The graphic design software is all on the Apple platform.
In order to facilitate the comparison of the HTTP protocol:
1) The protocol is HTTP (Hyper Text Protocol)
The common servers that implement this protocol are: Apacheiis et al. The customers are: IE, Mozilla, Netscape, etc.
2) The protocol is X
common servers that implement this protocol are: XFREE86, Xorg, XNEST, etc.
: All X applications.
but the server and client of the HTTP protocol are usually achieved between two different computers (servers and clients), so ordinary people are easier to understand this. The server and client program of the X protocol are usually on the same computer, so many users feel it is difficult to understand this. Since it is an agreement, it is definitely not related to the platform. Therefore The server's remote computer is even displayed on the Windows system equipped with the XNEST server. It's just that in most cases, the X application uses the X server of this machine, and then the X server outputs the display result to the display of the machine. This is why many people do not understand the reason for X.
Fourth, what is the relationship between X, X11, X11R6?
In I wonder if the beginner has noticed the directory/usr/x11r6. (The sixth edition of the X protocol is issued for the sixth edition) means that the X protocol currently used is the 11th edition, and then it has been corrected 6 times. The X protocols of different versions cannot be communicated, just like we can not communicate with IPv4 and IPv6 now, but don't worry, the current X server software and X applications follow X11R6.
These versions of these are the version number of the software XFREE86 that implements the X protocol. This is the concept of highly confused beginners.
protocol version and the software of implementation of the protocol -the difference between these two concepts. You know clearly Is it?
5. WM (Window Manager) window manager
The role of the window manager is to maximize, minimize, move, close, etc. Essence If there is no window manager, the X application can still start, but it is in the middle of the screen. It cannot be moved, minimized, not maximized, and no border.
XFREE86 comes with a simple window manager: TWM, and the window manager also has GNOME and KDE. In order to better understand the role of the window manager, we can do the following tests (because I use Ubuntu, it is impossible to confirm the correctness of the following operations and commands, please test the following and give me a correction).
1. After the system (linux with interface) starts, enter the graphic to enter the face, we open a XTERM, enter init3 to safely return to the character interface. Graphic interface, what you see is a complete graphic interface operating environment that uses the same complete graphics interface, you can maximize, minimize, move, close the window, etc.
3. We still enter the character interface again, press Ctrl Alt Backspace to reverse the character interface, enter: #xinit (not different from the command StartX in the second step), start the graphic interface again, what do you see what you see, what do you see? You see a XTERM. And you can't move. But you can enter the command to open the X application in this XTERM, if I enter: #Mozilla. Open the browser, is there any difference between the browser you see? He cannot move, minimize, maximum, and no borders in the middle of the screen.
Why are there such differences in the same X application? Because when we use StartX to start the graphical interface, we also started a default WM (ie window manager). If you use KDE If you use gnome to start GNOME, but when you use Xinit to start the graphical interface, you do not start WM.
4. If you use Xinit startup graphical interface and enter TWM ​​in XTERM, see what will be? Xternerm With a border, you can move, maximize, minimize this XTERM through this frame. TWM is a window manager in XFREE86. It is a relatively simple and simplest window manager, but he has window management All features of the device.
5. If you do not enter TWM ​​and enter gnome-session, you can start gnome or enter Startkde to start kde.
Other small window managers are:
, after step, Blackbox, FVWM, FVWM2, etc. are commonly used excellent window managers. There is in Redhat9 but not installed by default. You can install it. As long as Xinit can be used by WMAKER