redshift

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Thanks for this wonderful little program. I think it would be useful to have a command by which one could detect the current screen colour temperature. For instance:

'$ redshift --detect-temp'

Would that be possible? Is there any other way of doing this?

It is possible, simply analyse the current gamma ramps. I think these would do better in another program that is specialised at analysing the gamma ramps and could be able to do more than just give the current temperatures. redshift --detect-temp could then be implemented by spawning that program and read its output.

I have made some progress on this in a separate project. The gamma correction and brightness–contrast correction (which is not supported by redshift) can be calculated, but the calculation of the temperature is a bit off (but seems to always be within ±20 K, I assume this have to do with the accuracy we can have when applying a temperature the the gamma ramps). As of yet, redshift's fake backlight, called brightness, is not calculated.

If you just want the current temperature as calculated by Redshift, you can use the -p mode. If you want to know in general when some other program has changed the gamma ramp, the solution provided by @maandree is necessary.

Thanks, @jonis. That's exactly what I'd wanted.

Unfortunately "-p" does not work in the following example: redshift -O 4100 redshift -l geoclue2 -p Period: Daytime Color temperature: 5500K Brightness: 1.00

Wayne Sallee [email protected]

sorry for asking here but there is a similar command for blueshift?

I've never used blueshift, but here is what I ended up doing for redshift:

#!/bin/bash

# Uses redshift to shift the screen color from blue to read to blue.





case "${1}" in



blue)
color=$(cat /usr/share/redshifter/screencolor) # Get last used color.
echo "Last screen color temperature: "$color"K"
let "color = color +100"
if [ "$color" -ge "800" ]; then # Check for normal value.
if [ "$color" -gt "25000" ]; then # If to high, set to max color temperature.
color="25000"
fi
else
color="5500" # Something goofy, default to standard color temperature.
fi
echo "New screen color temperature: "$color"K"
echo $color > /usr/share/redshifter/screencolor # Save new color.
redshift -O $color




# Redshift: Temperature must be between 1000K and 25000K.




red)
color=$(cat /usr/share/redshifter/screencolor) # Get last used color.
echo "Last screen color temperature: "$color"K"
let "color = color - 100"
if [ "$color" -gt "0" ]; then # Check for normal value.
if [ "$color" -gt "25000" ]; then # If to high, set to max color temperature.
color="25000"
fi
if [ "$color" -lt "1000" ]; then # If to low, set to minimum color temperature.
color="1000"
fi
else
color="5500" # Something goofy, default to standard color temperature.
fi
echo "New screen color temperature: "$color"K"
echo $color > /usr/share/redshifter/screencolor # Save new color.
redshift -O $color








esac
exit

Wayne Sallee [email protected] http://www.WayneSallee.com

Just going to put this here...this supports shifting either the backlight or the color temperature by the specified value. Displays a notification with a progress bar to indicate the current level. Tested on Manjaro Xfce with libnotify version 0.8.3

Example usage (particularly useful if bound to hotkeys):

displayshift.sh light -25 #decreases brightness by 0.25
displayshift.sh light 10 #increases brightness by 0.1
displayshift.sh temp -500 #decreases color temperature by 500
displayshift.sh temp 200 #increases color temperature by 200

displayshift.sh:

#!/bin/bash

#usage: displayshift.sh [light|temp] [0-9]+
#light range: 1-100
#color range: 1000-25000


#--settings--

#notification icons (defaults are in papirus-icon-theme)
icolight="notification-display-brightness-medium"
icotemp="colortone"
icotemp_default="emblem-default" #shown when color temperature is exactly 6500 (default)

#cache location / files
cachefol="$HOME/.cache/displayshift"
cachelight="$cachefol/backlight.dat"
cachetemp="$cachefol/colortemp.dat"
cachenotid="$cachefol/notify.dat"


#--functions--
to_int(){ [[ "$1" =~ ^[\-]?[0-9]+$ ]] && echo "$1" || echo 0; }
msg_err(){ notify-send -i dialog-error "brightness" "$@" ; }
msg_light(){ notify-send -i $icolight -h int:value:${newlight} -r ${notid} -p " " ; }

msg_temp(){
  tempico="$icotemp"; [[ "$newtemp" = "6500" ]] && tempico="$icotemp_default"
  notify-send -i $tempico -h int:value:$((${newtemp}*4/1000)) -r ${notid} -p " "
}


#--main--

[[ -d "$cachefol" ]] || mkdir "$cachefol" || (msg_err "err: failed to create cache folder"; exit)


#read params
case "$1" in
  light) chnglight="$2"; chngtemp=0 ;;
  temp) chnglight=0; chngtemp="$2" ;;
  *) msg_err "err: invalid parameter"; exit ;;
esac
chnglight="$(to_int "$chnglight")"
chngtemp="$(to_int "$chngtemp")"


#read cache data
if [[ -f "$cachenotid" ]]; then
  notid="$(cat "$cachenotid")"
else notid=0; fi
notid="$(to_int "$notid")"

if [[ -f "$cachelight" ]]; then
  curlight="$(cat "$cachelight")"
  [[ "${curlight:0:1}" = "0" ]] && curlight="${curlight:1}"
else curlight=100; fi
curlight="$(to_int "$curlight")"

if [[ -f "$cachetemp" ]]; then
  curtemp="$(cat "$cachetemp")"
else curtemp=6500; fi
curtemp="$(to_int "$curtemp")"


#calculate new, ensure within valid range
newlight="$((curlight+chnglight))"
[[ "$newlight" -lt 1 ]] && newlight=1
[[ "$newlight" -gt 100 ]] && newlight=100
[[ "$newlight" -lt 100 ]] && newlight="0$newlight"

newtemp="$((curtemp+chngtemp))"
[[ "$newtemp" -lt 1000 ]] && newtemp=1000
[[ "$newtemp" -gt 25000 ]] && newtemp=25000


#make changes (if needed)
if ( [[ "$1" = "light" ]] && [[ ! "$newlight" = "$curlight" ]] ) || \
  ( [[ "$1" = "temp" ]] && [[ ! "$newtemp" = "$curtemp" ]] ); then

  if redshift -P -O $newtemp -b ${newlight:0:1}.${newlight:1:1}:${newlight:0:1}.${newlight:1:1}; then
    case $1 in
      light) echo "$newlight">"$cachelight" ;;
      temp) echo "$newtemp">"$cachetemp" ;;
    esac
  else msg_red "err: failed to run redshift with specified value"; exit; fi

fi


#final notification
case $1 in
  light) msg_light>"$cachenotid" ;;
  temp) msg_temp>"$cachenotid" ;;
esac