X11 related parameter settings

X11

Environment variables are DISPLAYused to set where to display graphics.

Log in to the graphical interface directly or use startx to start the graphics after logging in to the command line interface, the DISPLAY environment variable will be automatically set to 0:0

Variable format

The format of the DISPLAY environment variable is as follows host:NumA.NumB,

• hostRefers to where Xserver is locatedHost hostname or ip address, The graphics will be displayed on this machine. It can be a Linux/Unix machine with a graphical interface, or a Windows machine with Xserver running on Windows platforms such as Exceed, X-Deep/32, etc. If Host is empty, then Indicates that Xserver is running on this machine, and the graphics program (Xclient) uses unix socket to connect to Xserver, not TCP. When using TCP connection, NumA is the connected port minus the value of 6000. If NuMA is 0, it means Connect to port 6000; when using unix socket connection, it means the path of the connected unix socket, if it is 0, it means it is connected to /tmp/.X11-unix/X0. NumB is almost always 0

Xlib: connection to “:0.0” refused by server

Xlib: No protocol specifiedr
Error: Can’t open display: :0.0

This is because Xserver does not allow other users' graphics programs to be displayed on the current screen by default. If you need other users' graphics to be displayed on the current screen, you should use the currently logged-in user, that isThe user before switching identity executes the following command

xhost +

Instance

#切换用户前是root用户在使用图形程序
su - root

xhost +

su - oracle

root与oracle用户的DISPLAY都为:0.0

xhost is used to control X server access rights.
Usually when you log in from hostA to hostB and run the application on hostB, as the login and the logged-in, hostA is the client, but for graphics, it isDisplayed on hostA, Need to use hostA's Xserver, sohostA is server。

Therefore, before logging in to hostB, you need to run xhost+ on hostA to enable other users to access the Xserver of hostA.

On and off the screen display

#ubuntu16.04关掉图形界面启动，命令：
systemctl disable lightdm.service

#开启图形界面命令：
ln -s /lib/systemd/system/lightdm.service /etc/systemd/system/display-manager.service

Reset

sudo dpkg-reconfigure lightdm

other

关闭图形界面：
1.不可恢复：
sudo systemctl disable lightdm.service
2.可恢复：
sudo systemctl set-default multi-user.target

打开图形界面，分别针对上述1和2
1
sudo apt-get install --reinstall lightdm
2
sudo systemctl set-default graphical.target

Connect the actual screen

Confirm that the name of display of the actual screen is the value of DISPLAY

Requires running on the actual display screen

xdpyinfo |grep name

Different logins will cause different results, remember! Be sure to log in and run on the actual screen

xhost +
#运行结果：access control disabled, clients can connect from any host

Then the actual screen can be used by other login terminals, such as SSH terminal login. The
operation xdpyinfo |grep nameresult is:

Then run the interface program with ui and it will not be displayed on the actual screen. If you need to map to the actual screen, execute the following command:

#实际屏幕端，允许任意连接 或者加号后面带ip地址指定ip可以连接
xhost +

#ssh端设置DISPLAY,指定图形连接到localhost:0.0这里也就是我们在实际屏幕端查到的信息
export DISPLAY=:0.0
#以上没有错误，再ssh端，运行需要的程序即可显示到实际屏幕端
xxx

Set rotation

xrandr -o left 向左旋转90度
xrandr -o right 向右旋转90度
xrandr -o inverted 上下翻转
xrandr -o normal 回到正常角度
#通过xrandr读取显示屏id 为DSI-1，指定他旋转
xrandr --output DSI-1 --rotate left

Touch screen redirection

ubuntu multi-display single touch screen calibration

0, touch screen redirection

sudo xinput map-to-output 13 DP1  #将触摸屏映射到指定的显示器

• 13It is the ID of the touch screen device, which can be xinputviewed by commandILITEK ILITEK-TP id=13 [slave pointer (2)]

• DP1The name of the specified display device, which can be xrandrviewed through commands

1. Install the screen calibrator

sudo apt-get install xinput-calibrator

2. Check the screen resolution

Check the screen resolution in System settings --> Display

3. Manually set the size of the calibration window (used when there are multiple displays and only one touch screen, used to set only the specified window)

My computer has two monitors, one 1920x1080and one 1024x768, I only calibrate the left monitor, such as

Usage:xinput_calibrator --geometry x
–geometry: manually provide the geometry (width and height) for the calibration window

sudo xinput_calibrator --geometry 1920x1080
#注意：1920x1080　此处是字母x　

Warning: multiple calibratable devices found, calibrating last one (ILITEK ILITEK-TP)
use --device to select another one.
Setting calibration data: 0, 16384, 0, 9600
Calibrating EVDEV driver for “ILITEK ILITEK-TP” id=14
current calibration values (from XInput): min_x=0, max_x=16384 and min_y=0, max_y=9600

Doing dynamic recalibration:
Setting calibration data: 82, 32942, 155, 9796
–> Making the calibration permanent <–
copy the snippet below into ‘/etc/X11/xorg.conf.d/99-calibration.conf’ (/usr/share/X11/xorg.conf.d/ in some distro’s)
Section “InputClass”
Identifier “calibration”
MatchProduct “ILITEK ILITEK-TP”
Option “Calibration” “82 32942 155 9796”
Option “SwapAxes” “0”
EndSection

My computer is in the /usr/share/X11/xorg.conf.d/ directory

4. Follow the instructions to copy the calibration information to the following file

sudo gedit /usr/share/X11/xorg.conf.d/99-calibration.conf

Copy the content below

Section “InputClass”
Identifier “calibration”
MatchProduct “ILITEK ILITEK-TP”
Option “Calibration” “82 32942 155 9796”
Option “SwapAxes” “0”
EndSection

5. Finish.

1. Check how to use xinput_calibrator

xinput_calibrator -h

xinput_calibrator, v0.7.5

Usage: xinput_calibrator [-h|–help] [-v|–verbose] [–list] [–device ] [–precalib ] [–misclick ] [–output-type <auto|xorg.conf.d|hal|xinput>] [–fake] [–geometry x] [–no-timeout]
-h, --help: print this help message
-v, --verbose: print debug messages during the process
–list: list calibratable input devices and quit
–device <device name or XID or sysfs event name (e.g event5)>: select a specific device to calibrate
–precalib: manually provide the current calibration setting (eg. the values in xorg.conf)
–misclick: set the misclick threshold (0=off, default: 15 pixels)
–output-type <auto|xorg.conf.d|hal|xinput>: type of config to output (auto=automatically detect, default: auto)
–fake: emulate a fake device (for testing purposes)
–geometry: manually provide the geometry (width and height) for the calibration window
–no-timeout: turns off the timeout
–output-filename: write calibration data to file (USB: override default /etc/modprobe.conf.local

2. View input devices

xinput

⎡ Virtual core pointer id=2 [master pointer (3)]
⎜ ↳ Virtual core XTEST pointer id=4 [slave pointer (2)]
⎜ ↳ Logitech USB Receiver id=11 [slave pointer (2)]
⎜ ↳ ILITEK ILITEK-TP id=13 [slave pointer (2)]
⎜ ↳ ILITEK ILITEK-TP id=14 [slave pointer (2)]
⎣ Virtual core keyboard id=3 [master keyboard (2)]
↳ Virtual core XTEST keyboard id=5 [slave keyboard (3)]
↳ Power Button id=6 [slave keyboard (3)]
↳ Video Bus id=7 [slave keyboard (3)]
↳ Power Button id=8 [slave keyboard (3)]
↳ Sleep Button id=9 [slave keyboard (3)]
↳ Logitech USB Receiver id=10 [slave keyboard (3)]
↳ USB2.0 Camera
id=12 [slave keyboard (3)]

3. View the output device

xrandr

Screen 0: minimum 8 x 8, current 1920 x 1080, maximum 32767 x 32767
DP1 connected primary 1920x1080+0+0 (normal left inverted right x axis y axis) 521mm x 293mm
1920x1080 60.0*+
1680x1050 60.0
1280x1024 75.0 60.0
1440x900 59.9
1280x960 60.0
1280x720 60.0
1024x768 75.1 70.1 60.0
832x624 74.6
800x600 72.2 75.0 60.3 56.2
640x480 75.0 72.8 66.7 60.0
720x400 70.1
HDMI1 disconnected (normal left inverted right x axis y axis)
HDMI2 disconnected (normal left inverted right x axis y axis)
VIRTUAL1 disconnected (normal left inverted right x axis y axis)
实例参考