How to convert to grayscale?

[yrik]

Is there a way or trick to convert not to RGB/RGBA but to grayscale?
Or could you point out where to change the code so that I can prepare PR?

[jesusebzcp]

@yrik Hello how are you? you can use opencv to do it https://github.com/lukaszkurantdev/react-native-fast-opencv