Krita Python Scripting

Krita is built-in support of python and PyQt5
doc: https://docs.krita.org/en/user_manual/python_scripting.html
The built-in Script Editor is at Tool > Scripts > Scripter (you can test your code there)

Krita - a poweful painting and image editing tool

free and cross-platform: https://krita.org/en/

compare to Corel Painter and SAI, it has tons of brush to paint
compare to GIMP, it has supports for adjustment layer, independent masking, vector shape layer, editable text layer

however,
- GIMP has python scripting support, while Krita is written in C++ and its python API still on the way
  - https://krita.org/en/item/post-kickstarter-news/