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Setting a Compose key, in KDE Plasma keyboard settings, Advanced > Configure keyboard options I am seeing this :

enter image description here

What is a level?

And what does it mean something like "third level of Left Ctrl"? What does it mean to "choose a level"?

(I know how to set the Compose key, that's not my problem here: I'm asking about that terminology.)

cipricus
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2 Answers2

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  • Level 1: no modifications (e.g. pure a)
  • Level 2: usually Shift (e.g. shift+a -> A, so the character A is level 2 of the a-key)
  • Level 3: usually AltGr (e.g. AltGr+a -> æ, so character æ is level 3 of a as a key .. and so on)
  • Level 4: Shift+AltGr (e.g. Shift+AltGr+a -> Æ)
  • Level 5: needs to be defined by you, e.g. Windows-key (possible: Win+a -> à, often not predefined)

Examples depend on layout!

Formally a level 6 would be easy then via shift+level5-modifier. (e.g. shift+Win+a -> À)

A howto can be found here.

FelixJN
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  • If AltGr is level 3, what does "third level of Left Ctrl" mean as a Compose key? – cipricus Jun 26 '21 at 13:51
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    Sorry, for the confusion, I was a bit unclear: AltGr is the modifier, the third level of e.g. a is accessed AltGr+a. So starting compose key mode via LeftCtrl would be using the 3rd level modifier with left ctrl, i.e. AltGr+LCrtl. – FelixJN Jun 26 '21 at 13:54
  • Is AltGr the level or just a key that gives access to a "level". And does a level mean a set of characters that become accessible? It is this getting a third level for a layout? – cipricus Jun 26 '21 at 13:58
  • A key has levels, say you define for a -> "a A æ Æ à À", those would be levels 1 to 6. AltGr just grants access to the level (I called this "modifier"), this is the correct understanding. So if you access level 3 of LeftCtrl (via AltGr+LeftCtrl), you are in compose mode. – FelixJN Jun 26 '21 at 14:03
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    What "level" are the Ctrl-Alt-F1..12 key press combo's? I'm asking because I have a 60% keyboard with 5 rows of keys, and I can't toggle tty1-7 consoles in Debian. My f1-f12 keys are all combined on the number row, and are typed using the Fn shifter key. But an additional Fn shifter key has no affect in keypress combinations with Ctrl-Alt modifiers. But it doesn't work with the Ctrl-Alt-F1..7 key combos to change consoles. Anyone have an idea how to help? – user12711 Feb 12 '22 at 17:57
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    @user12711 - This is depending on the keyboard layout. Normally F keys have no such levels at all. You could maybe find a layout fitting your special keyboard. You should ask a separate question with all details. – cipricus Feb 28 '22 at 12:21
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As a complementary, shortened, easy-to-remember and basic answer, maybe useful for basic hasty forgetful users like myself, here's a scheme to remember:

enter image description here

"Capital" or "upper-key" meaning that, as expected, it's just about Shift, which capitalizes the typed letter - if that's what is typed, that is.

For the most cases, to me it's like this: the so-called 3rd level (AltGr) I see it as the main modifier, which always brings a new character (other than the basic-level-1) -- and the levels 2 and 4 are just capitalization of ones aforementioned with the help of Shift.

(For the image of any keyboard layout on any desktop, see this answer.)

cipricus
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