module.exports = { setupQuadratic: function(api) { var curve = api.getDefaultQuadratic(); api.setCurve(curve); }, setupCubic: function(api) { var curve = api.getDefaultCubic(); api.setCurve(curve); }, draw: function(api, curve) { api.reset(); api.drawSkeleton(curve); var i,t,p,tg,n,m,nd=20; for(i=0; i<=10; i++) { t = i/10.0; p = curve.get(t); tg = curve.derivative(t); m = Math.sqrt(tg.x*tg.x + tg.y*tg.y); tg = {x:tg.x/m, y:tg.y/m}; n = curve.normal(t); api.setColor("blue"); api.drawLine(p, {x:p.x+tg.x*nd, y:p.y+tg.y*nd}); api.setColor("red"); api.drawLine(p, {x:p.x+n.x*nd, y:p.y+n.y*nd}); api.setColor("black"); api.drawCircle(p,3); } } };