Midpoint circle algorithm implemented in Rust

midpoint_circle.rs

fn drawcircle(canvas: &mut Canvas<Window>, p: &mut Coordinate<i16>, r: f64, color: Color) {
    let mut x = r - 1;
    let mut y = 0;
    let px = p.x as i16;
    let py = p.y as i16;
    let mut dx = 1;
    let mut dy = 1;
    let mut err = dx - (r << 1);

    while x >= y {
        let _ = canvas.pixel(px + x, py + y, color);
        let _ = canvas.pixel(px + y, py + x, color);
        let _ = canvas.pixel(px - y, py + x, color);
        let _ = canvas.pixel(px - x, py + y, color);
        let _ = canvas.pixel(px - x, py - y, color);
        let _ = canvas.pixel(px - y, py - x, color);
        let _ = canvas.pixel(px + y, py - x, color);
        let _ = canvas.pixel(px + x, py - y, color);

        if err <= 0 {
            y += 1;
            err += dy;
            dy += 2;
        }

        if err > 0 {
            x -= 1;
            dx += 2;
            err += dx - (r << 1);
        }
    }
}