Function curve

docs/app/js/sanddance-app.js:129823–129826

(sx, sy, tx, ty)

};
const arcR = (sa, sr, ta, tr)=>arc(sr * Math.cos(sa), sr * Math.sin(sa), tr * Math.cos(ta), tr * Math.sin(ta));
const curve = (sx, sy, tx, ty)=>{
    const dx = tx - sx, dy = ty - sy, ix = 0.2 * (dx + dy), iy = 0.2 * (dy - dx);
    return "M" + sx + "," + sy + "C" + (sx + ix) + "," + (sy + iy) + " " + (tx + iy) + "," + (ty - ix) + " " + tx + "," + ty;
};
const curveR = (sa, sr, ta, tr)=>curve(sr * Math.cos(sa), sr * Math.sin(sa), tr * Math.cos(ta), tr * Math.sin(ta));
const orthoX = (sx, sy, tx, ty)=>"M" + sx + "," + sy + "V" + ty + "H" + tx;
const orthoY = (sx, sy, tx, ty)=>"M" + sx + "," + sy + "H" + tx + "V" + ty;