Cedilla under C (ç) in 'US international with dead keys' keyboard layout in Linux

I prefer to use US international with dead keys keyboard layout in order to get Latin diacritics for characters like é, è, à, etc in Libreoffice in Linux Mint.

On this layout characters like ´, `, ^, " are dead keys (clicked once do nothing) that can be pressed before other letters in order to get these signs.

' with a gives á
` with a gives à
" with a gives ä

etc, but

' with c gives ć

Can I get ç in this layout in Linux?

In Windows I do not have 'US international with dead keys' but only 'US international' which seems identical, only there dead-key ' with c gives ç (in both MSOffice and LibreOffice), which I think is the expected behavior.

I had imagined this might be a all-around system-level problem in Linux. But this keyboard layout (mentioned in a comment by user BramMooij under this question) can produce in Linux the cedilla under C (Ç) with AltGr-c.

Solution 1:

The key combination for ç in US international with dead keys layout was there all along, but unlike the other Latin diacritics it does not involve a dead key:

AltGr+,=ç

AltGr+Shift+,=Ç

Solution 2:

It's because the cedilla module isn't loaded by default when the locale is set to en, so you have to change the configuration files for gtk to add them:

1. Edit configuration files:

sudo vim /usr/lib/x86_64-linux-gnu/gtk-3.0/3.0.0/immodules.cache

sudo vim /usr/lib/x86_64-linux-gnu/gtk-2.0/2.10.0/immodules.cache

On both, find the lines starting with "cedilla" "Cedilla" and add :en to the line. Something like this:

"cedilla" "Cedilla" "gtk30" "/usr/share/locale" "az:ca:co:fr:gv:oc:pt:sq:tr:wa:en"

2. Change the Compose file:

sudo sed -i /usr/share/X11/locale/en_US.UTF-8/Compose -e 's/ć/ç/g' -e 's/Ć/Ç/g'

3. Instruct the system to load the cedilla module:

Add those lines to /etc/environment:

GTK_IM_MODULE=cedilla
QT_IM_MODULE=cedilla

Reboot and you are done.