2020.02.05 12:11 "Re: [Tiff] Inhaling an image all at once in scanline format", by John

I'm afraid that's it -- if your image has one-pixel high strips, you just have to read one-pixel high strips.

It's unusual to have such a thin strips, are you sure that's correct? tiffinfo is a handy way to double-check. If you have control over the writer, you could perhaps adjust it to write larger strips.

There's TIFFReadRGBAImage():

http://www.libtiff.org/man/TIFFReadRGBAImage.3t.html

Which will read the whole image in one go, but it's very likely to be slower than strip-wise reading, plus of course it will convert everything to RGBA.