Spanish to English Art/Literary Poetry & Literature music

From another poem by the same poet. Here is the context:

...si tu madre fuese una sombra sin brazos,
si tu amante acaso un muerto,
si todos los dias en tu contorno
brillaran agriamente las cenizas,
si el futuro de tus ojos al amanecer
lo pintara amenazante la penumbra,
no se si tu existieras
o si alguien pudiese existir en la agonia.

I'm looking for suggestions on translating the lines: si el futuro de tus ojos al amanecer / lo pintara amenazante la penumbra.

I'm not entirely sure what "lo" refers to here--el futuro? The grammar of these two lines baffles me a bit, as the phrase starts out with one subject (el futuro) and then ends with "la penumbra", which seems like it could be another subject... How do you read this?

Thanks,
Yvette