RGB interleaved format support?

[kobe2000]

Can I use following structure as the pixel type？

struct RGB {
    uint8_t r, g, b;
}

So I can reuse the image memory from app.

Is there any guide？

[dtschump]

I would rather suggest you use CImg<T>::permute_axes() to convert your RGBRGBRGB... buffer to a RRRR...GGGG....BBBB encoded buffer, and vice-versa.