Compose Key Issues – Some Apps Don’t Accept Characters from Compose Key

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The problem is that the compose key works fine, but some application doesn't accept some characters from it. E.g. I can type the character ∞ in Emacs (Compose+8+8), but this won't work in FireFox, Konsole and Kate. But many other characters, e.g. € typed there (in FireFox, Konsole and Kate) with Compose work just fine. Also I may insert a problem symbols with a simple copy-paste (from any of two clipboards).

So, what could cause it, and how to fix it?

Sorry, but I have no idea how to research the issue. I found people whose Compose key didn't worked at all in some apps, but in my case it is works, though somehow partially.

Setup: the compose key bound to the right Super key in both /etc/default/keyboard and KDE keyboard settings.

Best Answer

Thanks to @Gilles, I found an answer. So, the problem was with different Input Methods, used by different applications; and IMs in turn use different Compose files — ones used by X are /usr/share/X11/locale/<your-locale>/Compose and ~/.XCompose (the last isn't present by default, but you may create it for custom combinations), and the one used by Qt is in… Well, looks like nobody knows.

The solution is to set xim to be used as default input method by all applications. You can call im-config, and choose there xim as the default input method, or you can manually edit /etc/profile file to add these lines:

export GTK_IM_MODULE=xim
export XMODIFIERS=@im=xim
export QT_IM_MODULE=xim

Not sure about im-config, but for the way with /etc/profile reboot will be needed.

If you want the keys to act as dead keys:

There is already a limited mechanism for dead keys in Lisp, designed for 8-bit character sets on machines that don't have any way to input non-ASCII characters. If you type C-x 8 followed by an accent and a letter, the corresponding accented letter is inserted, thanks to the iso-transl library. We can copy this mechanism. Put this in your .emacs:

(define-key key-translation-map [dead-grave] (lookup-key key-translation-map "\C-x8`"))
(define-key key-translation-map [dead-acute] (lookup-key key-translation-map "\C-x8'"))
(define-key key-translation-map [dead-circumflex] (lookup-key key-translation-map "\C-x8^"))
(define-key key-translation-map [dead-diaeresis] (lookup-key key-translation-map "\C-x8\""))
(define-key key-translation-map [dead-tilde] (lookup-key key-translation-map "\C-x8~"))
(define-key isearch-mode-map [dead-grave] nil)
(define-key isearch-mode-map [dead-acute] nil)
(define-key isearch-mode-map [dead-circumflex] nil)
(define-key isearch-mode-map [dead-diaeresis] nil)
(define-key isearch-mode-map [dead-tilde] nil)

The map key-translation-map rewrites key sequences as they are entered, so this will make dead ` a equivalent to à for most purposes. Explicitly setting entries in isearch-mode-map to nil is necessary because otherwise pressing a dead key would exit isearch before the translation could kick in.

If you want the accent characters to be inserted immediately

(define-key key-translation-map [dead-grave] "`")
(define-key key-translation-map [dead-acute] "'")
(define-key key-translation-map [dead-circumflex] "^")
(define-key key-translation-map [dead-diaeresis] "\"")
(define-key key-translation-map [dead-tilde] "~")

How to Make Compose Work in GTK and Qt Apps

Found a solution which works for GTK apps (but not Qt). One needs to set

XMODIFIERS="@im=none"

to let X11 handle dead keys. Thanks to @PabloSaratxaga for his answer.

Best Answer

Related Solutions

Some keys are invalid on emacs when using German keyboard

If you want the keys to act as dead keys:

If you want the accent characters to be inserted immediately

How to Make Compose Work in GTK and Qt Apps

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