1 files changed, 31 insertions, 0 deletions
diff --git a/priv/static/js/metricsgraphics/misc/transitions.js b/priv/static/js/metricsgraphics/misc/transitions.js
new file mode 100644
index 0000000..da1e503
--- /dev/null
+++ b/priv/static/js/metricsgraphics/misc/transitions.js
@@ -0,0 +1,31 @@
+// http://bl.ocks.org/mbostock/3916621
+function path_tween(d1, precision) {
+  return function() {
+    var path0 = this,
+      path1 = path0.cloneNode(),
+      n0 = path0.getTotalLength() || 0,
+      n1 = (path1.setAttribute("d", d1), path1).getTotalLength() || 0;
+
+    // Uniform sampling of distance based on specified precision.
+    var distances = [0],
+      i = 0,
+      dt = precision / Math.max(n0, n1);
+    while ((i += dt) < 1) distances.push(i);
+    distances.push(1);
+
+    // Compute point-interpolators at each distance.
+    var points = distances.map(function(t) {
+      var p0 = path0.getPointAtLength(t * n0),
+        p1 = path1.getPointAtLength(t * n1);
+      return d3.interpolate([p0.x, p0.y], [p1.x, p1.y]);
+    });
+
+    return function(t) {
+      return t < 1 ? "M" + points.map(function(p) {
+        return p(t);
+      }).join("L") : d1;
+    };
+  };
+}
+
+MG.path_tween = path_tween;