Skin

[Duncan]

Francois Maurice posted on Fri, 09 Mar 2012 05:20:01 -0800 as excerpted:

> I'm a new user of KDE. Currently, I'm using RKWard, a graphical user
> interface for the R statistical computing environment.
>  
> I'd like to now if there is a way to change the appearence, "skin", for
> all applications running under KDE ?

That's an interesting question.  Yes... no... Both "all" and "under" in 
"all applications running under kde" have potential scope issues, and the 
answer clearly depends on the scope you had in mind when you asked the 
question.  This is probably a much longer reply than you intended, but 
FWIW, I'm known by regulars for my long and detailed posts, and it was 
fun writing up, so I hope you (and/or others who may come upon it as 
well) find it useful.  =:^)

If you intended to mean "all kde-based apps", then the answer is most 
certainly yes, you get the full control kde allows.

If you intended to mean "all qt-based apps, including kde apps (since kde 
is based on qt)", then yes, but with a few slight limitations since some 
options will apply to kde-apps-only.

If you intended to mean "all x-based apps, when run on a kde desktop", 
then the answer is yes, but with much stronger limitations, depending on 
the widget toolkit (qt, gtk, (tcl/)tk, fltk, others, roll-its-own) the 
applications widgets are based on.  In general, kde theming can be made 
to apply to gnome/gtk-based apps reasonably well but with some limits due 
to cross-toolkit differences, while the themeing/skinning flexibility of 
other toolkits, and/or kde's ability to get at it, tends to be much more 
limited, and apps based on them thus tend to do their own thing 
appearance-wise, to a much larger degree.

Extending the same logic to somewhat absurd levels, command-line and 
ncurses based (semi-gui) apps would certainly be included in the class of 
"all" apps, and when they're run in a terminal window on a kde desktop in 
X, they could certainly be said to be "running under kde", but not being 
X-based apps at all, only happening to be running in a terminal window 
under kde/X, kde normally has little or no control over their appearance.

Technically, that answers your question as asked, but not the implied 
question behind it -- where are kde's appearance options located and how 
do you change them?

You don't mention what version of kde, but I'll assume it's kde4.  Note 
that there were some major changes in settings layout for kde 4.5, and 
there are somewhat more minor changes with each feature release (the six-
month 4.x releases, so 4.0, 4.1, 4.2... up to current 4.8, monthly 4.x.y 
releases, so 4.8.0, 4.8.1 for the current 4.8 feature release, with 4.8.2 
and 4.8.3 to come, are bugfix-only and don't change layout, etc).  When I 
describe name and location of options, I'm doing so for the current kde 
4.8, but in most cases it'll be quite similar or identical for any kde 
since 4.5.  If you're still using 4.4 or earlier, you'll have to adjust 
the names and locations accordingly, and kde3 was enough different that 
if you're still using it, little if any of the below detail will apply, 
at least directly.

Most of these settings can be found in the application formerly known as 
kcontrol, now called kde settings or simply (and inaccurately) system 
settings.  Some distros may in fact call it something else, but whatever 
it's called, it's the kde settings control panel that you're looking 
for.  This control-panel-like app is split into categories and further 
into individual control panel applets, with many control panel applets 
further split into multiple tabs.

In kde settings (aka systemsettings), most of the appearance control 
options are located in two main categories, the difference of which isn't 
necessarily obvious to most users, who often find themselves looking in 
one, and if their desired settings aren't there, the other.  These are 
Common Appearance and Behavior, and Workspace Appearance and Behavior.

Under common appearance and behavior you'll find the sub-category 
application appearance, containing five applets, style, colors, icons, 
fonts, and emoticons.  Most of these, except for color and /maybe/ fonts 
(I'm not sure on fonts) only affect kde-based applications.  "Common" 
therefore refers to "common to most/all kde apps", and the other 
subcategories to be found under "Common..." likewise only affect kde-
based apps, in general.

The "Style" applet controls "widget style".  Widgets are all the little 
checkboxes (independently togglable), radiobuttons (only one of a group 
may be chosen, think the old-style car-radio station buttons, only one at 
a time could be chosen), comboboxes (dropdown lists), tabs, spinner-boxes 
(arrows increase/decrease a value), text-boxes, progressboxes, action 
buttons (like OK, Cancel), etc, that combine to form a GUI application.

The kde4 default style is Oxygen.  It also happens to be rather more 
highly configurable than the others.  But it's here in the style applet 
that you choose which style kde apps use, and how they're configured.

KDE4's color configuration options are much richer and therefore more 
complex than is common elsewhere.  The least complex way to change them 
and be sure everything's still readable is to use the pre-built color 
schemes.  If you don't like the ones that ship with kde, there's a lot 
more available on kde-look.org.  The get new schemes button allows you to 
download them.

If you do decide to tweak individual colors, be sure and click the help 
button and read up on how it works, first.  Once you understand the 
method to the madness, it's a LOT less confusing, and you'll know how to 
check that your changes don't leave you with say white text on eggshell 
background in some cases, something unreadable to nearly everyone.

Two additional notes on colors:  (1) On the options tab, there's an apply 
colors to non-kde4 applications checkbox.  This controls whether kde will 
try to apply its color scheme to gtk-based apps, etc, or not, thus 
forming the big exception to the "kde-only" rule of the "common" 
category..  FWIW, I have it set to apply to non-kde as well, but I've 
found that every once in awhile, my gtk-based apps revert to their 
default color scheme (which I hate for both kde and gtk, neutral grays 
aren't my thing AT ALL, and I tend to prefer "reverse" schemes with light 
text on dark backgrouns, as well) and I have to go back in here, toggle 
the setting off, hit apply, toggle it back on, and hit apply again. (2) 
The inactive/disabled color effects to be found here (togglable with a 
checkbox located a bit above the apply to non-kde checkbox I mentioned 
above) are nice, but don't always work well with the window translucency 
effect (see below).  So if you enable the window translucency effects and 
have inactive windows set to a higher translucency than active windows, 
you'll probably want to tone down or deactivate the inactive window color 
effects found here.

The icons, fonts, and emoticons applets are pretty self-explanatory, or 
at least I've found them so, and don't have much to say about them.


That's common appearance and behavior, now we'll switch to workspace 
appearance and behavior.  "Workspace" as opposed to "Common" refers to 
two rather different concepts.  First, the settings for plasma, the kde4 
desktop, are found here.  They only affect plasma (and krunner), not the 
rest of kde, but since plasma is the desktop, panels, launcher menus, 
etc, that you see when nothing else is loaded and that contain the system 
tray and notifiers, and that is normally used to launch apps, etc, most 
users will spend quite a bit of time looking at it, so its appearance is 
pretty important!

Second, "Workspace" contains the options for kwin, desktop effects, 
window behavior, window decorations, that apply to all apps, kde or not, 
since the window manager manages them all.  Thus, "workspace" contains 
app-specific configuration, but since one of those specific apps is kwin, 
the window manager, a lot of the "workspace" options apply even more 
globally than the "common" options above, because they apply to all X-
based apps, not just kde apps.

Desktop effects is directly under workspace..., no sub-category for it.  
While most of these effects are behavior more than appearance, on the all-
effects tab, there's a whole list of effects under appearance, but one of 
particular note, (window) translucency.  Since these effects are 
implemented by kde's window manager, kwin, they apply to all windows on 
the desktop, those of kde apps and non-kde apps alike.

If you chose to enable this effect, you'll almost certainly want to hit 
its configure button and adjust the relative transparency/opacity of the 
various elements.  Again I'll note what I said above under colors: if you 
set inactive windows somewhat transparent, you may want to tone down or 
deactivate inactive window color effects.  Also, if you have exception 
windows that you want to keep more transparent/opaque than normal even 
when inactive, you'll probably want to set inactive windows to full 
opacity here, and use the alternative described in the next paragraph.

Still in workspace appearance and behavior, under window behavior, window 
rules, you can set all sorts of individual window exceptions.  Most of 
them don't concern us here as we're dealing with appearance, but the 
opacity settings do, since they're appearance as well.

What I found here is that when I set inactive window opacity under 
desktop effects, translucency (as described above), that overrode 
individual window inactive translucency exceptions that I tried to set, 
here.

The fix was simple enough.  First, as mentioned above, I set inactive 
windows to full opacity in desktop effects.  Then, I created a new 
generic window rule applying to (almost) all windows, and set my desired 
default inactive window opacity there.  That rule should be BELOW any 
individual window exceptions in the list.  Here, it's my last entry, out 
of 25-30 different window rules I have setup with various exceptions for 
various windows, including an inactive window opacity exception for some 
of them.

The specific window rule settings for this generic rule?  (This describes 
4.8, 4.7 changed the window rule dialog layout, so 4.7 should be similar 
or identical, but 4.6 and earlier will need some adjustments.)

Window matching tab:  Description:  This is your description, for this 
one I chose "*all (opacity)".  Window types: All but Dock (panel) and 
Desktop.  In particular, I didn't want the panels fading when they 
weren't active, and they're dock windows, so I don't match on it.  For 
similar reasons I don't match on the desktop/root window.  Everything 
else on this tab should be set to unimportant, since we're setting up a 
generic rule. (The delay spinner is for click-selecting the window to 
apply to, it doesn't apply to the actual rule once setup).

Appearance and fixes tab (last):  Check the active and inactive opacity 
options, set them to force, and set the opacity as desired.  Here, I have 
99% active, 85% inactive.

Other settings on this tab, and the two middle tabs, should be left 
unchecked, unless of course you want to set default behavior for them, as 
well.

Hit OK, move the new rule to the bottom of the list if necessary, and hit 
apply.  You now have a default setting for active and inactive window 
translucency, but can override it with other specific window rules, as 
long as they appear above this one in the window rules list. =:^)


Back under the main workspace appearance and behavior category, look 
under workspace appearance.  Available applets here include window 
decorations, cursor theme, desktop theme, and splash screen.  Cursor 
theme is a general X/window-manager setting and should apply to all apps, 
unless they specifically set their own cursors.  Splash screen controls 
what appears as kde first starts up.  That leaves window decorations and 
desktop theme.

Window decorations will apply to all windows that have the normal window 
border and titlebar, so it's not kde specific, but some windows (the 
krunner dialog, for instance) are borderless by default.  (If you have 
the hide window borders toggle hotkey set, you can try toggling the 
border on and off for various windows, including krunner.  Krunner does 
look rather odd with a window title and border! =:^)  Here again, as with 
styles under common, above, the kde default is oxygen, and here again, 
it's noticeably more configurable than other options.  FWIW, I prefer the 
oxygen style above, but the kde2 window decoration, here.  It's worth 
noting that the decoration colors (for most decorations) are set in the 
colors applet, dealt with above, not here.

Desktop theme applies to the plasma desktop (desktop, panels, plasmoids 
including the kickoff launcher and clock, etc) and to krunner, only.  One 
possible point of confusion is that the font and colors settings under 
common, above, do *NOT* in general apply to plasma.  Instead, the desktop 
theme settings apply.  There's a kde oxygen desktop theme just as there's 
an oxygen widget style and an oxygen window decoration, and an oxygen 
icon theme, as well.  Two other things of note.  As with color schemes 
and various other places in kde where it makes sense, you can download 
additional desktop themes from kde-look.org, if you don't like the look 
of any of those shipped with kde.  And, on the details tab, it's possible 
to mix and match elements from installed desktop themes as desired.  
Thus, for instance, if you like one theme in general, but dislike its 
kickoff element and particularly like the analog clock from a different 
theme, it's possible to have everything except for those two elements 
from the same theme, and set those two, each to the corresponding element 
from a different theme.


That about covers it except for one additional note.  At least here, I 
have trouble keeping themes (as in desktop themes, aka plasmoid's 
appearance), decorations (as in window decorations, aka window titlebars 
and borders), and styles (as in widget styles, the buttons, checkboxes, 
etc, that together form the interactive UI of an app) separate.  When I 
look at all three of them in kde settings, I can tell which is which, but 
I do often have to either see all three or click on them one at a time 
until I get the one I'm looking for.  I suppose I'm not alone in this, 
and that as with common appearance and behavior vs workspace appearance 
and behavior, where I've seen other people wondering about the 
distinction, it's a bit confusing to many people.  If you find it 
confusing too, at least note that all three exist, so that if you don't 
get the one you intended with the first one you open, you can look around 
and try the others, as well.

-- 
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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