rewrite to handler.js format

components/sections/intersections/handler.js

@@ -0,0 +1,75 @@
+var min = Math.min, max = Math.max;
+
+module.exports = {
+  setupLines: function(api) {
+    var curve1 = new api.Bezier([50,50,150,110]);
+    var curve2 = new api.Bezier([50,250,170,170]);
+    api.setCurve(curve1, curve2);
+  },
+
+  drawLineIntersection: function(api, curves) {
+    api.reset();
+
+    var lli = api.utils.lli4;
+    var p = lli(
+      curves[0].points[0],
+      curves[0].points[1],
+      curves[1].points[0],
+      curves[1].points[1]
+    );
+
+    var mark = 0;
+    curves.forEach(curve => {
+      api.drawSkeleton(curve);
+      api.setColor("black");
+      if (p) {
+        var pts = curve.points,
+            mx = min(pts[0].x, pts[1].x),
+            my = min(pts[0].y, pts[1].y),
+            Mx = max(pts[0].x, pts[1].x),
+            My = max(pts[0].y, pts[1].y);
+        if (mx <= p.x && my <= p.y && Mx >= p.x && My >= p.y) {
+          api.setColor("#00FF00");
+          mark++;
+        }
+      }
+      api.drawCurve(curve);
+    });
+
+    if (p) {
+      api.setColor(mark < 2 ? "red" : "#00FF00");
+      api.drawCircle(p, 3);
+    }
+  },
+
+  setupQuadratic: function(api) {
+    var curve1 = api.getDefaultQuadratic();
+    var curve2 = new api.Bezier([15,250,220,20]);
+    api.setCurve(curve1, curve2);
+  },
+
+  setupCubic: function(api) {
+    var curve1 = new api.Bezier([100,240, 30,60, 210,230, 160,30]);
+    var curve2 = new api.Bezier([25,260, 230,20]);
+    api.setCurve(curve1, curve2);
+  },
+
+  draw: function(api, curves) {
+    api.reset();
+    curves.forEach(curve => {
+      api.drawSkeleton(curve);
+      api.drawCurve(curve);
+    });
+
+    var utils = api.utils;
+    var line = { p1: curves[1].points[0], p2: curves[1].points[1] };
+    var acpts = utils.align(curves[0].points, line);
+    var nB = new api.Bezier(acpts);
+    var roots = utils.roots(nB.points);
+    roots.forEach(t => {
+      var p = curves[0].get(t);
+      api.drawCircle(p, 3);
+      api.text("t = " + t, {x: p.x + 5, y: p.y + 10});
+    });
+  }
+};