refactor: avoid strange round-trip of draw_fn arguments

[Integral-Tech]

• There is a strange round-trip of draw_fn arguments:

let (draw_fn, pad, style) = draw::get_draw_function();
draw_fn(pad, style, ...);

Refactor code to avoid the unnecessary round-trip.

• Although format! macro is very powerful, it introduces overhead of memory allocation on the heap compared to &str. Therefore, when format! macro is unnecessary, we should avoid using it.