rewrite to handler.js format

components/sections/pointvectors/handler.js

@@ -0,0 +1,32 @@
+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);
+    }
+  }
+};