Scrollbars hard to see

Mon Nov 30 00:45:36 GMT 2009

Anne Wilson posted on Sun, 29 Nov 2009 11:50:52 +0000 as excerpted:

> On Sunday 29 November 2009 10:51:29 Dotan Cohen wrote:
>> > By changing your theme?  No, I'm not being sarcastic.  Some things
>> > are hard- coded into themes, and this may be one of them.
>> 
>> That is quite what I did as a workaround.
>> 
>> > As a matter of interest, which theme are you finding hard to see?
>> > This is something I haven't noticed in any theme I've tried.
>> 
>> Oxygen in particular suffers from many usability issues, this is one of
>> them. Most of the other themes suffer from this as well, as the
>> scrollbar is the same colour as the window background.
>> 
> Strange.  I'm using oxygen at the moment, and I don't see any problem
> with the scrollbar - and my eyes are really not that good.  There seems
> to be quite good contrast between the scroll 'handle' and its
> background.

A lot of it depends on the monitor and its brightness/contrast (aka 
hardware) settings, and on the configured gamma.

Dotan, have you tried fiddling with "The application formerly known as 
kcontrol" (generically aka system settings, tho it's really kde settings 
and has little to do with the rest of the system, so kcontrol is more 
accurate /and/ less generic), Computer admin, Display, Gamma?

According to the kgamma handbook (khelpcenter), the defaults are 1.00 X, 
1.80 Mac, 2.20 MSWormOS (my name for it, FWIW).  If you haven't done the 
calibration, go ahead and do it, following the procedure outlined in the 
kgamma handbook.  On my LCDs, I ended up with an RGB gamma of 1.25 red 
and green, 1.65 blue.  That /dramatically/ improved the contrast at the 
dark end of things, for me.  Note that CRTs will likely come out with far 
different numbers, and there's all sorts of other factors involved as 
well, from the backlite (florescent or LED) on LCDs and possible screen 
coatings on CRTs, to typical ambient lighting conditions, to make and 
model of monitor, to specific monitor on the same production run, to 
personal preference, to...

That will make a big difference, or at least it did here.

As for changing the scrollbar specifically, that's controlled by look and 
feel, appearance, colors, but there's not an individual setting for it.  
After your gamma is set correctly, you may want to tweak the colors a bit 
anyway.

Here, I have a STRONG preference for light foregrounds/text, dark 
backgrounds, AND for way more color than the wimpy/sickly default mostly-
grays so I started by finding a scheme that came at least reasonably 
close to meeting my needs. Of the default kde themes, Obsidian Coast and 
Wonton Soup came closest, being at least light on dark, but they were 
still way too sickly weak for my tastes.  kdelook to the rescue! =:^)  
The best one I found there was darkblue-deb, a theme Debian may ship, 
apparently, or at least a Debian fan created! =:^)

But it wasn't /exactly/ right, either, tho it came reasonably close.  So 
I had to tweak it a bit.

If you are going to do *any* color tweaking on your own, besides changing 
the schemes, you **NEED** to read the associated help page.  If you 
don't, you will not understand what you are doing, and will likely get 
/something/ wrong, such that you'll get a dialog or tooltip text or 
/something/, with "invisible" text (or invisible thumb buttons on the 
scrollbar, as in this thread, etc), simply due to not paying attention to 
how the various color sets and color roles combine, in some cases with 
automatic settings based on the others.  After Mathew and I hashed things 
out on this list a couple versions ago, the color settings dialog is
/much/ improved over what it was, but kde4 has an incredibly rich and 
complex color layout, WAY more complex than kde3, and if you don't read 
that help text, you WILL miss some of the nuances and very likely screw
/something/ up.

That said, the most important point to remember is to check any changes 
you make in the preview.  Note that on the colors tab, choosing any color 
set other than the default "common colors" from the dropdown, you get a 
more detailed preview of how the various roles of that color set in their 
normal and alternate state look.  If ANY of those words don't have enough 
foreground/background contrast to easily read the words, you WILL have 
problems when the associated color set and role comes up.  Thus, if you 
can't read any of those words, you better go back and tweak your colors 
some more!

One other detail to note!  The Oxygen style (kcontrol, look&feel, 
appearance, styles) does button gradients/hilites that the other styles 
don't do.  I don't know the precise algorithm behind it, and the effect 
only seems to be noticeable if the button color is dark enough so many 
probably won't see it at all, but if your chosen button background color 
is dark enough and you're running Oxygen style, you should notice a 
definite difference between the button background color you set in 
colors, and the actual button background color as shown on the system -- 
the color will be the same hue, but lighter than the color selected in 
the color settings dialog, due to the Oxygen button hiliting effect.  
FWIW, once I realized that, after a bit of experimentation, I settled on 
a very very dark red (with an even smaller touch of green, #140800), so 
dark many people would call it black, as the button normal background 
setting.  The hiliting effect lightens it to a dark (but not black) 
brown, which sets off nicely against the window and view background blues 
of darkblue-deb, as well as the bright yellow I chose (another mod from 
darkblue-deb) as my button text color.  However, during the 
experimentation I tried green as well, and noted the same lightening 
effect there.  I expect that blue would have it as well, but didn't test 
that since with window and view normal backgrounds already dark blue 
(from darkblue-deb), dark-blue buttons wouldn't show up so well!

Meanwhile, the precise color settings controlling the scrollbar are 
window normal background, for the scrollbar background, and button normal 
background, for the scroll button.  Again, be sure and check your 
previews when you change them tho, ensuring that all the text roles still 
show up as sufficiently readable, and if you're running Oxygen style and 
have a dark button normal background, consider the effect when it's 
lightened a bit due to that hiliting, when you check those previews!

-- 
Duncan - List replies preferred.   No HTML msgs.
"Every nonfree program has a lord, a master --
and if you use the program, he is your master."  Richard Stallman

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