Ibrahimovic has arrived in the Catalan capital and was due to undergo a medical on Monday before signing his new contract with the European champions.
Inter have agreed to swap Ibrahimovic for Barca's Cameroon forward Samuel Eto'o plus a reported fee of around 40 million euros ($56.8 million) and Belarus midfielder Aleksandr Hleb is set to join the Italian club on loan as part of the deal.
"It's difficult to explain my feelings," Ibrahimovic told Barca television.
"We are almost there, only my signature is missing," he added. "I am very, very happy and once everything has been done I will be the happiest man in the world."
The Swede, 28, said he was a "very boring person" and spent most of his free time at home with his family.
"I am a professional footballer, very relaxed," he told Barca TV. "I like making other people happy. If they are happy then I am too."