Bar graph added.

node_modules/vega-scenegraph/src/path/trail.js

@@ -0,0 +1,116 @@
+import {Tau} from '../util/constants';
+import {path} from 'd3-path';
+
+export default function() {
+  var x,
+      y,
+      size,
+      defined,
+      context = null,
+      ready, x1, y1, r1;
+
+  function point(x2, y2, w2) {
+    var r2 = w2 / 2;
+
+    if (ready) {
+      var ux = y1 - y2,
+          uy = x2 - x1;
+
+      if (ux || uy) {
+        // get normal vector
+        var ud = Math.sqrt(ux * ux + uy * uy),
+            rx = (ux /= ud) * r1,
+            ry = (uy /= ud) * r1,
+            t = Math.atan2(uy, ux);
+
+        // draw segment
+        context.moveTo(x1 - rx, y1 - ry);
+        context.lineTo(x2 - ux * r2, y2 - uy * r2);
+        context.arc(x2, y2, r2, t - Math.PI, t);
+        context.lineTo(x1 + rx, y1 + ry);
+        context.arc(x1, y1, r1, t, t + Math.PI);
+      } else {
+        context.arc(x2, y2, r2, 0, Tau);
+      }
+      context.closePath();
+    } else {
+      ready = 1;
+    }
+    x1 = x2;
+    y1 = y2;
+    r1 = r2;
+  }
+
+  function trail(data) {
+    var i,
+        n = data.length,
+        d,
+        defined0 = false,
+        buffer;
+
+    if (context == null) context = buffer = path();
+
+    for (i = 0; i <= n; ++i) {
+      if (!(i < n && defined(d = data[i], i, data)) === defined0) {
+        if (defined0 = !defined0) ready = 0;
+      }
+      if (defined0) point(+x(d, i, data), +y(d, i, data), +size(d, i, data));
+    }
+
+    if (buffer) {
+      context = null;
+      return buffer + '' || null;
+    }
+  }
+
+  trail.x = function(_) {
+    if (arguments.length) {
+      x = _;
+      return trail;
+    } else {
+      return x;
+    }
+  };
+
+  trail.y = function(_) {
+    if (arguments.length) {
+      y = _;
+      return trail;
+    } else {
+      return y;
+    }
+  };
+
+  trail.size = function(_) {
+    if (arguments.length) {
+      size = _;
+      return trail;
+    } else {
+      return size;
+    }
+  };
+
+  trail.defined = function(_) {
+    if (arguments.length) {
+      defined = _;
+      return trail;
+    } else {
+      return defined;
+    }
+  };
+
+  trail.context = function(_) {
+    if (arguments.length) {
+      if (_ == null) {
+        context = null;
+      } else {
+        context = _;
+      }
+      return trail;
+    } else {
+      return context;
+    }
+  };
+
+  return trail;
+}