- A Voyager's Companion

LCD Screen Brightness
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Author:  Microyacht [ 18 Mar 2015, 19:15 ]
Post subject:  LCD Screen Brightness

Where do I find the Brightness Control for the LCD Screen Brightness. When my machine was running WindowsXP or Vista, it was found in CONTROL PANEL in settings and it was generally MUCH brighter!


Author:  Moe [ 19 Mar 2015, 03:43 ]
Post subject:  Re: LCD Screen Brightness

The brightness for your display is controlled by the Sun...I kid you not.

There's a post about this and the little lightbulb icon in the lower right corner.

Additionally, there is a little script I think should also be integrated

activeOutput=$(xrandr | grep -e " connected [^(]" | sed -e "s/\([A-Z0-9]\+\) connected.*/\1/")
alpha=`zenity --scale --text "Brightness" --min-value=10 --max-value=100 --value=50`
alpha=`echo $alpha / 100 | bc -l`
`xrandr --output $activeOutput --brightness $alpha`
The trouble is integrating it into the pre-existing automagic configuration.

For funzies,
mkdir ~/bin
medit ~/bin/brightness-level
Paste in the code, exit, and then then
chmod +x ~/bin/brightness-level
to make it executable.

It can be called up from the terminal after the command prompt
A window pops up, and you can adjust your backlight (at least on this machine that I use) from full to "bright enough to see on a moonless overcast night, but not so bright it really screws up your nightvision"...I mean--it's almost off.

There are a number of problems, aside from the initial trauma of setting it up,
  • how to make it work in most every situation (computer), or not make the situation worse if it doesn't work on every computer
  • work automatically, or in union with the automagic system currently in place.

A menu entry is plus because if I want to tweak, sometimes it's just as easy to point and click.

Similar, or unique in mostly only in name, is a 'desktop' file, essentially a 'shortcut' for 'Desktop' shortcuts, or 'Menu' shortcuts (same file, different location) . This is the 'same' desktop file in the brimmer project.
medit ~/.local/share/applications/brightness-level
[Desktop Entry]
Name=Brightness Level
Comment=Change backlight setting on LCDs
Exec= ./bin/brightness-level
Save, exit, and test. Place a copy on your Desktop for a "desktop" shortcut.

Money, time and monkeys

Author:  Microyacht [ 19 Mar 2015, 05:34 ]
Post subject:  Re: LCD Screen Brightness

Thank you Moe.

I took the unit outside on a bright but not sunny day and would not be able to see it clear enough for Navigation. It came with Windows Vista and ten thousand bugs but I found there was a brightness control which by default (as it was a new Vista installation done by the company who sold it to me) was set to only 30%. When I cranked it up to 100% it was visible in quite bright sunlight!

I'll have a play with the unit later today.


PS: Unit = Panasonic Toughbook CF-N1

Author:  Moe [ 19 Mar 2015, 12:05 ]
Post subject:  Re: LCD Screen Brightness

Just to stress, out of the box, the system thinks it's in Panama. The outside/extreme time frame for a system location update is 15 minutes after the gps has gotten a fix. That is to say, every fifteen minutes the system checks with the gps to update a reference file (two actually, /etc/ and /etc/nx.lon) for all those quiet applications that don't need steaming hot gps data, but like to have an idea where they are. (Airmail, Stellarium, Redshift)

The nightshift/redshift reference those files to know when the sun has gone down, or come up.

can't wait the 15 minute maximum, enter gpspos in the terminal...don't have a gps handy, then hand edit the two files with gksudo medit /etc/ /etc/nx.lon.

People living in other areas of the planet might not have updated the location with gps while the system was running. If this is the case, they could be looking at night time settings and be confused with the function, or apparent dysfunction.

Author:  Microyacht [ 02 Apr 2015, 11:46 ]
Post subject:  Re: LCD Screen Brightness

Sorry, I AM still here. Had to clear out the spare room (my computer and radio room) for decorating and tidy up for a friend to use for a few days. I did discover that the brightness (Dullness! LOL) was already on maximum and not viewable outside. Would be no good in the cockpit unless it was night-time. My second Panasonic CF-H1 is just the same. Maybe the H2 is much brighter but to expensive to find out!

Thanks for your help.

Bye for now - Steve/G4MJW

Author:  Moe [ 03 Apr 2015, 02:49 ]
Post subject:  Re: LCD Screen Brightness

Screen brightness is measured in nits, that's candela per square metre, they tell me.

While screen brightness is subjective, the extent to which they can be driven is not. Most displays for consumer grade computers run 200-400 nits. Sunlight read-able displays are over 2,000 nits.

When it come to using a display in broad daylight, there is no magic. There is a flat out competition for your retina. It's the source that makes the difference...or suitable modified with a squint, hand for a blinker, and the shade of the dodger.

Author:  Microyacht [ 04 Apr 2015, 04:23 ]
Post subject:  Re: LCD Screen Brightness

Hi Moe, Many thanks for all yr help. Well, I have some success.

I remembered command line: xgamma

And it was set to 1.0 which I assumed was as bright as it would appear to my eyes!

xgamma -gamma 0.5 (tried 0.25 and 0.1) and the effective brightness reduces. Suddenly thought: "What IF" I tried going above 1, like 1.5! Hey-presto it increases each RGB to that factor and is now viewable outside. Going above 3.0 and it starts to "Wash-out", lacking in contrast. So, re-capping, I've left it set to:

xgamma -gamma 1.5


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