What is the principal image in “kaʾanna al-shamsa alqat ridāʾahā ʿalayhi”?

Ṭarafah ibn al-ʿAbd: Ruins, Ships, Gazelle, and Beauty (Verses 1–10)

• an actual cloth covering the face
• the sun setting
• the camel-litter sinking in the sea
• sunlight portrayed as a cloak covering the face