Contributing translations and, doing so, helping improving Luminance HDR is very easy.
The translation process is managed through the web-based Transifex platform.
You can spend few minutes of your time, whenever you want, just translating few strings of the UI in your native language or helping reviewing the work of other translators. If you are not a developer and still willing to help, please read the guide Getting Started as a Translator|Transifex Documentation
If instead you are a developer contributing code to the Luminance HDR project, you might be interested in the information given below.
Managing the translations is implemented using a CMake option (UPDATE_TRANSLATIONS). When changes are made to the UI, setting this option to TRUE will force make to update the files containing the translations in the i18n directory (Qt's lupdate will be called). You can then rerun CMAKE with the option set to OFF.
To synchronize the local content with the Transifex online platform, you first install the Transifex Client, available for Windows, Linux, Mac.
Open a command shell and navigate (CD) into the i18n directory of Luminance HDR source tree.
The first time you use the client you need to initialize it with your credentials. Therefore type:
tx initIf after an lupdate you want to update the strings online, you do
tx push -s -tIn order to download the translated strings do
tx pull -aMore options for each operation is available in the help
tx helpor
tx help push