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 Post subject: How do i adjust brightness on old navigatrix system?

Joined: 06 Jan 2013, 16:56
Posts: 62
I had a spare laptop with old navigatrix installed (4.1); only use to to surf the net, it is so stable that i never bother to upgrade it. The function key for brightness control does not seem to work and I cannot find any where in the preferences settings to adjust the brightness, so how do I adjust the brightness?

 Post subject: Re: How do i adjust brightness on old navigatrix system?

Joined: 04 Nov 2010, 20:51
Posts: 1062
Redshift/nightshift, software that controls the 'redness' of the screen through the
redshift.png [ 4.04 KiB | Viewed 10964 times ]
icon in the lower right corner of the tool panel also controls the 'brightness'

Redshift/nightshift has three settings, Off/ Civilised/ Nightshift.

Off, is off. There is no adjustment of the brightness OR colour of the display.

Civilised is full colour temp and brightness during the day while the sun is above the horizon, but after the sun goes down the screen slowly dims to 30% backlight and the colour temperture warms to be easy on the eyes for night time work.

The nightshift mode is the same, except as the sun goes gown, the backlighting and the colour temperature go as low as possible. This is great for running at night. (Some work still needs to be done for visual accuity, but that's the nature of the beast.)

You toggle between the three settings by clicking the icon. Most of the time it isn't noticeable except if it's after the sun has gone down, or a gps has not been connected to the system and it still 'thinks' it's in Panama.

Most of the time this works flawless, except if you get older, or need extra backlighting for other reasons.

If you manually adjust the settings, the next time the system verifies the brightness/redness setting it will revert to to the default settings. Handy, or frustrating, depending how you look at it.

This is why I wrote this little script to set the brightness for *my favourite setting*, the civilised setting, to give a new goal.

Open a terminal (<ctrl><alt><t>) and at the prompt enter:
gksu medit /usr/local/bin/brimmer /usr/share/applications/brimmer.desktop
This open two blank files in the text editor.

In the first blank file, paste in:
# Brighter-Dimmer
# This script can be used in the Navigatrix system
# in conjunction with redshift/nightshift display
# modifications to set 0-100% of LCD Backlight Range
# of the 10 step backlight scale (0-9) provided
# by most current LCD displays

brimmer=$(zenity --title "Brimmer - the brighter dimmer" --scale --text "Set the Brightness, or dimness, on a scale of 0-100" --min-value=0 --max-value=100 --value=30 --step 10)

# Navigatrix sets the colour temp to create the best of all possible worlds
# OFF, no change; Civilised, easy on the eyes night use; and FULL, for the
# rhodopsin sparing red as you can get with what you've got setting.

# The config file is...

# read it
cat $shiftsettings >$

# Locate and substitute the new input values and re-write the file.
# To change the backlight from ONLY the 'Civilised' setting to both 'light' and 'dark'
# change 'lightx=' to 'x='.  Change it to 'darkx=' for ONLY the 'Night Vision Red'
# Change it to anything else to have it not work at all.
sed "s/lightx=\"\?[[:digit:]]\{1,3\}\"/lightx=\"$brimmer\"/g" <$ >$shiftsettings

# Do it even if it's wrong.
nightshift restore
#             ^ the syntax: nightshift [dark|light|toggle|restore|off]

# ...but cleanup when you're done.
rm $
In the second blank file, paste in:
[Desktop Entry]
Name=Brighter Dimmer
Comment=Brighter Dimmer to re/set LCD backlight for Navigatix Redshift/Nightshift
Exec=gksu --description /usr/share/applications/brimmer.desktop /usr/local/bin/brimmer
Make the script you created executable:
sudo chmod +x /usr/local/bin/brimmer
Now, the Menu entry is created in "Preferences". It will be near the top called "Brighter Dimmer"

When you run this application, the brightness/dimness of the "civilised" setting will stay at the level you want, and not revert to 30% backlighting.

Does that answer your question, Ken?

 Post subject: Re: How do i adjust brightness on old navigatrix system?

Joined: 06 Jan 2013, 16:56
Posts: 62
Thks Moe,
I found a simple command "xgamma -gamma 1.0" and by changing the value to say 0.75, or 0.5 the brightness can be reduced.

A longer command that also seems to work is "sudo setpci -s 00:02.0 F4.B=xx" where xx bet 0 & FF with FF being the brightess


 Post subject: Re: How do i adjust brightness on old navigatrix system?

Joined: 04 Nov 2010, 20:51
Posts: 1062
The xgamma command sets the gamma of the display. I've looked it up before and the only thing I really understand is there are three colours, Red, Green, Blue. When you adjust their gamma, you do it on a scale generally from zero to one.

This is what redshift/nighshift is doing in the background.

On some pre-calculated timeframe of the computer and the position of the Sun, the gammas of the Red, Green, and Blue are smoothly transitioned, so depending on the setting, always easy on the eyes.

I think it was David who rigged it up so the backlighting for LED/LCD displays would cycle as well.

Most of the time it works really well, and nearly transparently, but I'm finding as I get older, and the finer nature of some of the work I do, I need more light, either task lighting or backlighting on the computer display.

The problem is sometimes with small text, or poor contrast, more light is the solution.

If it is only for a short while, the keyboard function keys, those blue lettering keys, as the redshift/nightshift will reset it back to what pre-calculated setting would be.

The Brighter Dimmer was created for folks like me who need a little more light for a little longer time period.

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