Function draw_text 

pub fn draw_text(
    buf: &mut [u8],
    buf_w: i32,
    buf_h: i32,
    x0: i32,
    y0: i32,
    text: &str,
    color: [u8; 3],
    window_alpha: f32,
    bgr: bool,
)

Blit text into buf (pre-multiplied, buf_w×buf_h, 4 bpp) with top-left at (x0, y0). color is straight RGB; window_alpha scales the whole draw (fade); bgr selects byte order (true → B,G,R,A as Wayland ARGB8888-on-LE / X11 ARGB / Win32 BGRA expect, false → R,G,B,A).