const RAD = Math.PI / 180;

function bound(x: number, y: number, w: number, h: number, deg: number) {
    const rcos = Math.cos(deg * RAD);
    const rsin = Math.sin(deg * RAD);

    let left = 0;
    let top = 0;
    let right = 0;
    let bottom = 0;

    if (rcos >= 0 && rsin >= 0) { // top, right
        left = x - h * rsin;
        top = y;
        right = x + w * rcos;
        bottom = y + w * rsin + h * rcos;
    } else if (rcos < 0 && rsin >= 0) { // bottom, right
        left =  x - h * rsin + w * rcos;
        top = y + h * rcos;
        right = x;
        bottom = y + w * rsin;
    } else if (rcos < 0 && rsin < 0) { // bottom, left
        left =  x + w * rcos;
        top = y + w * rsin + h * rcos;
        right = x - h * rsin;
        bottom = y;
    } else { // top, left
        left = x;
        top = y + w * rsin;
        right = x + w * rcos - h * rsin;
        bottom = y + h * rcos;
    }

    return { left, top, right, bottom };
}