How to change screen resolution using xrandr

Change the resolution on distros based on GNOME o KDE very simple. For those who use open box and derivatives, the matter is a bit more complicated. Most of the time, this results in a lengthy explanation of how to change the configuration file of the X server: xorg.conf, located in etc / X11. Although there is nothing wrong with this method, xorg.conf has been deprecated and can be intimidating for many users. Use xrandr it's more fast y simple. In addition, it has several graphical interfaces and can be used to other necessities very interesting, such as the configuration of dual monitors, etc.

How to use xrandr

First, list the different resolutions available for your monitor:

xrandr -q

In case the resolution you are looking for is not listed, it may be because your monitor does not really support it or you need to install a better driver (ati, intel, or nvidia).

Then, set the resolution you want to use (change "1400 × 1050" to the desired resolution):

xrandr -s 1400x1050

Adjusting the dpi

The dpi differs from the resolution of your screen (referenced as pixels x inch) and affects the decorations of the windows, the size of the same, the rendering of the fonts, etc.

On many monitors, xrandr will set the dpi automatically. If not, or if you prefer to change this configuration, you can specify it manually:

xrandr --dpi 96 -s 1400x1050

If that fails, you can specify the dpi in ~ / .Xdefaults

I opened an editor and put the following in that file:

xft.dpi: 96

This dpi will be applied to all the new windows you open. You can also log out to see the results of this change (no need to restart the system).

If 96 is not the right dpi for you, you can try 72 or 135.

Dual monitors

It is also possible to use xrandr to configure dual monitors. To do this, you must make use of the –right-of and –left-of options.

Here's an example, using an nvidia card:

First, list the monitors using xrandr.

xrandr -q

The result will be something like the following:

Screen 0: minimum 320 x 200, current 1920 x 1200, maximum 4096 x 4096
DVI-I-1 connected 1920x1200 + 0 + 0 (izannormal left inverted right x axis y axis) 520mm x 320mm
1920 × 1200 60.0 * +
1600 × 1200 60.0
1680 × 1050 60.0
1280 × 1024 75.0
1280 × 960 60.0
1152 × 864 75.0
1024 × 768 75.1 70.1 60.0
832 × 624 74.6
800 × 600 72.2 75.0 60.3 56.2
640 × 480 72.8 75.0 60.0
720 × 400 70.1
DVI-I-2 connected 1920x1200 + 0 + 0 (normal left inverted right x axis and axis) 520mm x 320mm
1920 × 1200 60.0 * +
1600 × 1200 60.0
1680 × 1050 60.0
1280 × 1024 75.0
1280 × 960 60.0
1152 × 864 75.0
1024 × 768 75.1 70.1 60.0
832 × 624 74.6
800 × 600 72.2 75.0 60.3 56.2
640 × 480 72.8 75.0 60.0
720 × 400 70.1
TV-1 disconnected (Normal Left inverted Right X axis and axis)

Then use xrandr to configure the monitors. Change the names "DVI-I-1" and "DVI-I-2" to the names of your monitors. You may also need to adjust the resolution and change “–left-of” to “–right-of”.

xrandr --auto --output DVI-I-2 --mode 1920x1200 --left-of DVI-I-1

It has the same effect as:

xrandr --auto --output DVI-I-1 --mode 1920x1200 --right-of DVI-I-2

To set the primary monitor, use the –primary option:

xrandr --auto --output DVI-I-1 --mode 1920x1200 --primary --right-of DVI-I-2

Configure xrandr to boot at startup

This method varies depending on the desktop environment you use (gnome, kde, xfce).

In openbox, add the xrandr command in ~ / .config / openbox / autostart.sh.

In fluxbox, do the same operation but in the file ~ / .fluxbox / startup

Depending on the desktop environment you use, you can add xrandr in ~ / .xinit

Graphical tools

There are very good graphical interfaces for xrandr. Among the best known, we can mention lxrandr, grandr, krandr and arandr.