Function ui_text_area 

pub fn ui_text_area(
    id: u32,
    x: f32,
    y: f32,
    w: f32,
    h: f32,
    initial: &str,
) -> String

Render a multi-line text area of height h (pixels). Returns the current UTF-8 text.

initial seeds the widget the first time this id is seen. Prefer a buffer large enough for your document (out_cap is currently 131072 bytes — see implementation).

Typed Enter inserts a newline. Use for editors, compose boxes, JSON buffers, etc.