MuPDF - How to save the separations to png or gray image using MUPDF C++

Question

I am developing a pdf separation viewer app using Mupdf (c++) library.

I need to know is there any possibility to on/off the separation/colors.

Or else export all separation/colors into separate png files.

I trying multiple methods. but it didn't work. Because MuPDF hasn't better documentation.

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