Arabic calligraphy styles
Diwani is the hand of decoration and occasion. Its words press together on a rising line and its letters curl into one another, so a phrase comes out looking like a single knot. It was born in the Ottoman chancery and now lives on cards and certificates.
Diwani grew in the chancery of the Ottoman state after the conquest of Constantinople, and its invention is usually credited to Housam Roumi. Decrees and firmans were written in it, and the tight interlocking of its letters made a document hard to add to or to forge once it was written. A heavier version came out of it, Diwani Jali, whose gaps are filled with dots and small marks until no white is left. It stayed the official hand of the state until the end of the empire.
Look at the line before you look at the letters. In Diwani it climbs from right to left instead of running flat. The letters slope and curve, one word slides into the next, and the endings turn back into the middle of the phrase. In Diwani Jali you also see small dots and marks packed into every gap.
You find it on invitations, certificates, awards, and titles that want ornament. It is common as well in Arabic logos that are after movement and grace.
Start with what defines Diwani: set your text on a rising path or an arch, then edit each letter on its own until one word slides into its neighbour, and stretch the kashida to carry the join. Fill the space with tashkeel and marks the way Diwani Jali does, then export your work as a vector file.
Open the editor, write your phrase, and shape its letters yourself. The account is free and one word is enough to start.