Use Color Utils
QUIQQER now has it's own JS color utils:
https://dev.quiqqer.com/quiqqer/quiqqer/blob/dev/lib/QUI/Projects/Media/Utils.php
They should be used instead of the Calendar Color Helper:
https://dev.quiqqer.com/quiqqer/calendar/blob/bebfb995402cd8c27350f59cdbd81f2fc48ff2f1/bin/classes/ColorHelper.js