Gfilui

How do I add user-defined compose key rules in Ubuntu 18.04? I turned my Compose key on using Gnome Tweaks (it's on CapsLock), created a .XCompose starting with these lines:

include "%L" # import the default Compose file for your locale

# IPA

<Multi_key> <a> <h> : "ɑ" 
<Multi_key> <A> <h> : "â±­"
# Some more lines
<Multi_key> <ampersand> <underscore> <m> : "̼"



# Math

<Multi_key> <minus> <0> : "−"
<Multi_key> <asterisk> <1> : "⋅"
<Multi_key> <x> <x> : "×"
# ...

I followed this advice, installed uim and set it as GTK_ and QT_IM_MODULE but every sequence starting with the <minus> <0> line gets ignored. When I tried xim, it did a bit better but it made gedit glitch:

.

When I tried GTK_IM_MODULE=gtk-im-context-simple, most of the sequences started working, but some of them just don't.

<Multi_key> <minus> <0> : "−" # doesn't work
<Multi_key> <asterisk> <1> : "⋅" # doesn't work
<Multi_key> <e> <m> <o> <colon> <space> : "😶" # works
<Multi_key> <e> <m> <o> <colon> <Up> : "🙄" # works
<Multi_key> <e> <m> <o> <x> <asterisk> <space> : "😙" # doesn't work
<Multi_key> <e> <m> <o> <c> <a> <l> <l> : "🤙" # doesn't work
<Multi_key> <e> <m> <o> <o> <k> : "👌" # works
<Multi_key> <w> <t> <f> : "ಠ_ಠ" # doesn't work
<Multi_key> <w> <h> <y> : "ლ(ಠ益ಠლ)" # doesn't work
<Multi_key> <0> <space> : "​" # zero-width space doesn't work

.

What should I do to make my Compose key work properly?

The link you point to is basically correct, with a few caveats:

• 
  

  Compose inserts the character corresponding to the first (shortest) match. Suppose .XCompose contains the following entries:

  
  
  

   <Multi_key> <space> : " " nobreakspace # NO-BREAK SPACE
   <Multi_key> <space> <space> : " " U2002 # EN SPACE
   <Multi_key> <space> <space> <space> : " " U2003 # EM SPACE
  

  
  
  

  Attempts to use EN-SPACE or EM-SPACE will never work.

  
  


• 
  

  To get Compose to work with GTK, add the following line to .profile:

  
  
  

  export GTK_IM_MODULE=gtk-im-context-simple