Reference :
G'MIC-Qt, is a plug-in to bring G'MIC capabilities to the image retouching and painting softwareG'MIC is a full-featured open-source framework for digital image processing, distributed under the CeCILL free software licenses (LGPL-like and/or GPL-compatible). It provides several user interfaces to convert / process / visualize generic image datasets, ranging from 1D scalar signals to 3D+t sequences of multi-spectral volumetric images, hence including 2D color images.
https://gmic.eu/