New feature in Czkawka 4.0 is ability to translate interface of GTK app.

App use Fluent localization system -

Main/Default language is English, but also Polish is officially supported.

Translating is mostly done by site -

If you want to translate Czkawka to your language, you can do it in this site.

Next chapters are only for internal use, so just use crowdin page.

How to translate Czkawka?

Base translatable strings are placed under i18n/en/czkawka_gui.ftl file.
czkawka_core.ftl is just a symlink which point to file from above(I had problems with splitting string into two separate crates)

Since such strings are heavily integrated into build system, so to check status of translation it is required to recompile Czkawka.

czkawka_gui.ftl file contains lines in this format:
id_of_message = translated_string

upper_manual_add_included_button_tooltip = Allows to add directory name to search by hand

to create new folder with translations, it is required to create copy of i18n/en folder and give it name from ISO 639-1 code standard - e.g. pl, en, ru, fr etc.

Next only translated strings needs to be changed

Such translated file, can be easily uploaded to crowdin page to increase % of translated strings

Testing translation

Replacing en folder

The simplest method is to remove en folder and replace it with needed one.
Next Czkawka needs to be compiled and run.

Adding new translation

Recommended way to test translation, is to add it directly to Czkawka source code.

After creating proper and well named folder and translating string inside it, to be able to be able to choose this language file it is required to modify czkawka_gui/src/ file.

pub const LANGUAGES_ALL: [Language; 2] = [
    Language {
        combo_box_text: "English",
        short_text: "en",
    Language {
        combo_box_text: "Polski (Polish)",
        short_text: "pl",

The only thing which is required to change is LANGUAGES_ALL constant.

Number of items must be changed [Language; 2] -> [Language; 3].

Next new record must be added to array.
combo_box_text must contains native and english name of language e.g. Polski (Polish) - English is only exception because in both versions is exactly same.
short_text is ISO 639-1 code which need to match with county code and name of folder inside i18n.

    Language {
        combo_box_text: "Polski (Polish)",
        short_text: "pl",

Validating translation offline

When trying to translate objects offline, due renames, adding and removing elements, may happen that translations will contain outdated entries.

To help find such keywords, special python script can be used.

To be able to use it, be sure that you are directly inside main czkawka folder.
Next, be sure that your language is available in array/list and also in i18n folder and then run python script python3 misc/
Then results should be visible in console:

Checking pl language
Missing keyword - duplicate_mode_name_combo_box
Missing keyword - duplicate_mode_size_combo_box
Missing keyword - duplicate_mode_hash_combo_box
Missing keyword - settings_language_label_tooltip
Missing keyword - settings_language_label
Unused keyword - duplicate_mode_name_checkbox
Unused keyword - duplicate_mode_size_checkbox
Unused keyword - duplicate_mode_hash_checkbox
Unused keyword - duplicate_mode_name_checkbox_tooltip
Unused keyword - duplicate_mode_size_checkbox_tooltip
Unused keyword - duplicate_mode_hash_checkbox_tooltip

Missing keyword means that some keywords exists in base translations and texts needs to be translated.
Unused keyword means that keyword is no longer used. It can be renamed or entirely removed from file.

When script will not print anything except “Checking language”, then this means that translation file have exactly same keys as base one.

Computer Translations

Some languages in settings, will have annotation that were created by computers.
Such translations will have a lot of errors, so manual checking of each string is required.