Which calligrapher's creative background is described in the poem "Take off your hat and show off the top of the princes"? Thank you for your questions.

Grass saint Zhang Xu. Take off your hat and show your head in front of princes and ministers, and write on paper with a pen, as elegant as a cloud in the sky. It shows Cao Sheng's wild and uninhibited writing. He rode a horse after drinking, swaying like a boat. He fell into the well with dim eyes and fell asleep at the bottom of the well. Li Xian, the king of Ruyang, drank three glasses of wine and went to see the son of heaven. On the way, I met a car filled with distiller's yeast, and the smell of wine made my mouth water. It's a pity that it can't be sealed in Jiuquan County, where the water tastes like wine. Shi Li, the right-hand man, spends thousands of dollars to drink like a whale swallowing the water of a hundred rivers in order to rise every day. It is claimed that the purpose of drinking is to get rid of politics and make way for beauty. Cui Zongzhi is a handsome young man. When he has a drink, he often looks up at the sky. His handsome figure is like a well-proportioned tree. Although Su Jin fasted before the Buddha, he often forgot the Buddhist precepts when drinking. Li Bai can write hundreds of poems in no time after drinking ten barrels. He goes to Chang 'an Avenue to drink and often sleeps in restaurants. The son of heaven gave a banquet in the lake and asked him to preface the poem. He refused to get on the boat because he was drunk, claiming to be Brewmaster. Zhang Xu drank three glasses of wine and wrote a book with a brush. People called him Cao Xian. He often takes off his hat in front of princes and nobles and scribbles books. If God helps him, his book will be like a cloud of smoke on the paper. After drinking five glasses of wine, I regained my spirits. The conversation at the banquet often surprises everyone.