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# Redshift

From ArchWiki

From the Redshift project web page:

  Redshift adjusts the color temperature of your screen according to your surroundings. This may help your eyes hurt less if you are working in front of the screen at night. This program is inspired by the closed-source application f.lux.

Note Redshift does not support Wayland [1]. See Backlight#Wayland for alternatives.

## Installation

Install the redshift package. Alternatively, install the redshift-minimalAUR package, for a version with minimal dependencies.

### Front ends

The redshift-gtk command comes with the redshift package and provides a system tray icon for controlling Redshift. See optional dependencies.

Alternatives are redshift-qtAUR or redshiftconfAUR.

## Usage

Redshift will at least need your location to start (unless `-O` is used), meaning the latitude and longitude of your location. Redshift employs several routines for obtaining your location. If none of them works (e.g. none of the used helper programs is installed), you need to enter your location manually.

### Quick start

To just get it up and running with a basic setup, issue:

    $ redshift -l LATITUDE:LONGITUDE

where `LATITUDE` is the latitude and `LONGITUDE` is the longitude of your location.

Tip You can get the coordinates of a place with GeoNames.org.

To instantly adjust the color temperature of your screen use:

    $ redshift -P -O TEMPERATURE

where `TEMPERATURE` is the desired color temperature (between `1000` and `25000`).

### Autostart

There are several options to have Redshift automatically started:

- By right-clicking the system tray icon and selecting Autostart when redshift-gtk or plasma5-applets-redshift-control is already launched.
- By placing a Redshift desktop entry in `~/.config/autostart/` or by adding `redshift` to your window manager or desktop environment's autostarting method.
- By using the user units provided: `redshift.service` and `redshift-gtk.service`. Activate only one of them depending on whether or not you want the system tray icon.

Note

- The Redshift service files contain `Restart=always` so they will restart infinitely. See systemd.service(5).
- When using a systemd user service, Xorg must be started before execution of the service, which is not the case without a display manager. Otherwise you will get `RANDR Query Version' returned error -1` and `Initialization of randr failed`. This is already accounted for in the systemd/User method above, which contains `After=display-manager.service`.

### Toggle

Redshift will continously update the color temperature at regular intervals. One shot mode can be selected if you only want to do one adjustment. The color adjustments done by Redshift can be temporarily toggled on and off by sending it the USR1 signal:

    $ pkill -USR1 redshift

## Configuration

Redshift reads the configuration file `~/.config/redshift/redshift.conf` [2] if it exists. However, Redshift does not create that configuration file, so you may want to create it manually. See redshift.conf.sample.

### Specify location manually

Redshift calculates the sunrise and sunset times based on geographic coordinates. It can be specified manually by using the `manual` location-provider, e.g. for Paris:

    ~/.config/redshift/redshift.conf

    [redshift]
    ...
    location-provider=manual
    ...
    [manual]
    lat=48.864716
    lon=2.349014

### Automatic location based on GeoClue

Redshift uses the `geoclue2` location-provider by default. It needs a GeoClue agent running in the background. It is supposed to work without further configuration, but if you experience problems, see #Unable to connect to GeoClue.

### Automatic location based on GPSD

You can also use gpsd to automatically determine your GPS location and use it as an input for Redshift. Create the following script and pass `$lat` and `$lon` to `redshift -l $lat:$lon`:

    #!/bin/bash
    date
    #gpsdata=$( gpspipe -w -n 10 |   grep -m 1 lon )
    gpsdata=$( gpspipe -w | grep -m 1 TPV )
    lat=$( echo "$gpsdata"  | jsawk 'return this.lat' )
    lon=$( echo "$gpsdata"  | jsawk 'return this.lon' )
    alt=$( echo "$gpsdata"  | jsawk 'return this.alt' )
    dt=$( echo "$gpsdata" | jsawk 'return this.time' )
    echo "$dt"
    echo "You are here: $lat, $lon at $alt"

For more information, see this forums thread.

### Use real screen brightness

Redshift has a brightness adjustment setting, but it does not work the way most people might expect. In fact it is a fake brightness adjustment obtained by manipulating the gamma ramps, which means that it does not reduce the backlight of the screen. [3]

Changing screen backlight is possible with redshift hooks and acpilightAUR, but there are some limitations and you may have to find another method of controlling the backlight depending on your hardware.

You need to create a file in `~/.config/redshift/hooks` and make it executable. You can use and edit the following example:

    ~/.config/redshift/hooks/brightness.sh

    #!/bin/sh
    # Set brightness via xbrightness when redshift status changes

    # Set brightness values for each status.
    # Range from 1 to 100 is valid
    brightness_day=85
    brightness_transition=50
    brightness_night=30
    # Set fps for smoooooth transition
    fps=1000
    # Adjust this grep to filter only the backlights you want to adjust
    backlights=($(xbacklight -list | grep ddcci*))

    set_brightness() {
    	for backlight in "${backlights[@]}"
    	do
    		xbacklight -set $1 -fps $fps -ctrl $backlight &
    	done
    }

    if [ "$1" = period-changed ]; then
    	case $3 in
    		night)
    			set_brightness $brightness_night
    			;;
    		transition)
    			set_brightness $brightness_transition
    			;;
    		daytime)
    			set_brightness $brightness_day
    			;;
    	esac
    fi

Make it executable and restart the `redshift.service` to apply changes.

Check the service status as it should not contain the following message:

    redshift[..]: No outputs have backlight property

## Troubleshooting

### Unable to connect to GeoClue

If running `$ redshift` and you are getting:

    Unable to obtain GeoClue client path: Timeout was reached.

Then make sure that a GeoClue agent is running. GNOME Shell provides an agent itself. For other desktop environments, a demo agent (`/usr/lib/geoclue-2.0/demos/agent`) is autostarted. You can check if GeoClue works properly by checking the output of the `/usr/lib/geoclue-2.0/demos/where-am-i` command.

If you are using a desktop environment that does not support XDG Autostart, then you have to start the demo agent manually, or you can create a systemd unit file with the following config:

    ~/.config/systemd/user/geoclue-agent.service

    [Unit]
    Description=redshift needs to get a (geo)clue

    [Service]
    ExecStart=/usr/lib/geoclue-2.0/demos/agent

    [Install]
    WantedBy=default.target

Then start/enable the `geoclue-agent.service` user unit.

### Screen 1 could not be found

Locate configuration-file "redshift.conf" in your distribution and change "screen 1" to "screen 0".

### Left/right clicking the tray icon does not work

Install libappindicator. See redshift issue 363 and FS#49971.

### Redshift makes the screen quickly flicker between the set color value of the screen and the default color value

Make sure there are not multiple instances of redshift running.

### Redshift works fine when invoked as a command but fails when run as a systemd service

The systemd unit has a line in the `redshift.service` file that makes the service wait until the `display-manager.service` unit is started by a display manager before the unit will invoke `redshift`. If you do not use a display manager, edit the `redshift.service` user service and delete the `After=display-manager.service` line. Run a daemon-reload and the service should initialize properly.

### Redshift-gtk service causes core-dumping

Refer to the previous problem and to [4].

### Redshift does not appear in system tray

If running the `$ redshift-gtk` command does not start in the system tray, but instead you get the following output

    $ redshift-gtk

    Traceback (most recent call last):
      File "/usr/bin/redshift-gtk", line 26, in <module>
        from redshift_gtk.statusicon import run
      File "/usr/lib/python3.8/site-packages/redshift_gtk/statusicon.py", line 31, in <module>
        gi.require_version('Gtk', '3.0')
    AttributeError: module 'gi' has no attribute 'require_version'

you will need to install python-gobject.

### Redshift turns the screen green when resolution is over 1080p while using Nvidia drivers

This is a bug with the nvidia drivers. A fix for this is to make the following edit:

    /etc/X11/xorg.conf.d/20-nvidia.conf

    Section "Device"
        ...
        Option         "UseNvKmsCompositionPipeline" "false"
        ...
    EndSection

For more information, see redshift issue 587 and redshift issue 720.

### Redshift does not support hotkey for toggling

A workaround is to create a custom hotkey in your desktop environment calling the command `pkill -USR1 '^redshift$'`.

For more information, see [5].

## See also

- Redshift website
- Redshift on GitHub
- Wikipedia:Redshift (software)
- Similar software: redshift-schedulerAUR, blugonAUR

Categories:

- X server
- Eye candy

Redshift
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