Function mupdf_sys::fz_invert_pixmap_luminance

pub unsafe extern "C" fn fz_invert_pixmap_luminance(
    ctx: *mut fz_context, 
    pix: *mut fz_pixmap
)

Transform the pixels in a pixmap so that luminance of each pixel is inverted, and the chrominance remains unchanged (as much as accuracy allows).

All components of all pixels are inverted (except alpha, which is unchanged). Only supports Grey and RGB bitmaps.