NAME
	radharc - Reduce eye strain and improve sleep.

PRONUNCIATION
	ɹˈaɪɐrk (depending on dialect)

SYNOPSIS
	radharc [OPTIONS]...

	The -l option is mandatory, unless single value -t is used.

OPTIONS
	-l LATITUDE:LONGITUDE
		Tell radharc where you are. This is mandatory.
		The values are measured in degrees and in the
		GPS (you probably do not have too care about that,
		the differences between the systems should not
		be significant another), and must be in decimal.

		Reminder for Americans (particularly US Americans),
		you are an the western hemisphere, not the eastern,
		thus your longtiude is negative. If you experience
		weird colour temperatures, 100 % of the times it is
		because you forgot the minus sign. But no need to
		feel stupid, it is a really common mistake.

		No complicated stuff please, only latitudes within
		±90° and longitudes within ±180°. No unit thought.

	-t DAY:NIGHT
		Select colour temperature to use during full daytime
		and full night. This should be a integer. Do not
		include the unit (the 'K'). The temperatures must
		be at least 1000 K.

	-t TEMPERATURE
		Select temperature to use. The program will exit
		when it is done setting the temperature. The
		natural colour temperature is 6500 K ('-t 6500').
		The temperature must be at least 1000 K.

	-t +DELTA
		Increase the colour temperature by DELTA kelvin.

	-t -DELTA
		Decrease the colour temperature by DELTA kelvin.

	-T TEMPERATURE
		Temperature that shall be used when the program
		is disabled (via SIGUSR1).

	-p	Print the current status.

	-n	Set the temperature immediately, do not transition.

	-N	Do not transition when exiting, disabling, or
		reenabling.

	-o	Set the colour, and exit.

	-x	Ignore the current calibrations on the monitors.

	-s SECONDS
		The start and exit transitions shall take SECONDS
		seconds. This may be a floating point number, with
		an explicit unit.

	-S KELVINS
		The transitions speed, in kelvin per second.
		This most be a positive integer.

	-i
		Apply negative image filter. Radharc will detect
		which monitors have this one when it starts.

	-h PATHNAME
		Use a hook script for events.

	-b
		Broadcast events with bus.

	-d SERVER=DISPLAY
		Use the display server whose identifier is
		DISPLAY and whose identifier is stored in the
		environment variable SERVER, for example
		-d DISPLAY=:0 for the X display :0.

	-d SYSTEM
		Use a subsystem which does not have identifiers.
		For example 'drm' for the Direct Rendering Manager.
		You can also select 'none', this is useful if you
		don't want any adjustments, but want events to be
		broadcasted.

	-e EDID
		Select monitor to use by its EDID.

	-m NUM
		Select monitor to use by its global index.

	-m SCREEN:NUM
		Select monitor to use by its index without
		a screen or graphic card. The later is for when
		not inside a graphics environment.

	All options also have a '+' variant, for example '+n'.
	These undo the affect of previous '-' variant.
	'+d', '+e', and '+m' all undo the affect of all previous
	'-d', '-e', and '-m' options (not respectively).
	Additionally, with the exception of '-d', '-e', '-m',
	subsequent options override the previous of the the option.

SIGNALS
	SIGHUP
		Perform an online update to a newer version.

	SIGUSR1
		Enable or disable radharc.

	SIGUSR2
		Toggle negative image filter. Enable on all
		monitors if it is enable on some but not all.

	SIGRTMIN+N
		Toggle negative image on monitor N, if monitors
		have been selected manually, it will be in the
		order they where selected.

ENVIRONMENT
	XDG_RUNTIME_DIR
		This environment variable names the directory in which
		the state file is stored. If unset or empty, /run is
		used.

	RADHARC_STATE
		The pathname to the state file, will be determined
		automatically if not set. If not set, you may only
		have one instance running per display server instance.

RATIONALE
	Your location is determined use GeoClue because it clunky,
	unreliable, inaccurate and requires an Internet connection
	or GPS device, it is way to common that neither is available.
	And I do not want to handle all bug reports for this. Besides,
	you can use an external program.

	Your timezone is used to determine your location approximately
	when not specified, You can be a really poor approximation.
	It is too much work supporting summer time, especially when
	summer time is not necessarily +1 hour, additionally you can
	have scheme where it is first normal time, then summer time,
	then double summer time, then back to summer time, and the back
	normal time; complicated stuff, additionally, the Russian
	Federation is in permanent summer time. And have you heard about
	the People's Republic of China (not to be confused with the
	less known Republic of China,) they have one timezone, which is
	far from in the middle of the country. You can use an external
	program. To keep it simple, we are not even using your timezone
	to santity check your specified location.

NOTES
	I suggest using a local script named radharc that sets all
	options for you.

KNOWN ISSUES
	In X.org, the gamma ramps do not apply to hardware cursors,
	because the developers thinks it is the graphics drivers
	that shall fix this, and they are not accepting patches for
	this. You can use xorg-server-hwcursor-gamma, however, that
	patched version does not apply apply the gamma ramps until
	the cursor changes image. You can also use sortware cursors
	if this really bothers you.

	Wayland does not support this because it [Wayland] sucks.

	Haiku does not support this yet.

SEE ALSO
	redshift(1), blueshift(1), redshift-adjust(1), nightshift(1),
	locateme(1)