--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/toolkit/javascript/d3/src/layout/stack.js	Thu Apr 10 14:20:23 2014 +0200
@@ -0,0 +1,237 @@
+// data is two-dimensional array of x,y; we populate y0
+d3.layout.stack = function() {
+  var values = Object,
+      order = d3_layout_stackOrders["default"],
+      offset = d3_layout_stackOffsets["zero"],
+      out = d3_layout_stackOut,
+      x = d3_layout_stackX,
+      y = d3_layout_stackY;
+
+  function stack(data, index) {
+
+    // Convert series to canonical two-dimensional representation.
+    var series = data.map(function(d, i) {
+      return values.call(stack, d, i);
+    });
+
+    // Convert each series to canonical [[x,y]] representation.
+    var points = series.map(function(d, i) {
+      return d.map(function(v, i) {
+        return [x.call(stack, v, i), y.call(stack, v, i)];
+      });
+    });
+
+    // Compute the order of series, and permute them.
+    var orders = order.call(stack, points, index);
+    series = d3.permute(series, orders);
+    points = d3.permute(points, orders);
+
+    // Compute the baseline…
+    var offsets = offset.call(stack, points, index);
+
+    // And propagate it to other series.
+    var n = series.length,
+        m = series[0].length,
+        i,
+        j,
+        o;
+    for (j = 0; j < m; ++j) {
+      out.call(stack, series[0][j], o = offsets[j], points[0][j][1]);
+      for (i = 1; i < n; ++i) {
+        out.call(stack, series[i][j], o += points[i - 1][j][1], points[i][j][1]);
+      }
+    }
+
+    return data;
+  }
+
+  stack.values = function(x) {
+    if (!arguments.length) return values;
+    values = x;
+    return stack;
+  };
+
+  stack.order = function(x) {
+    if (!arguments.length) return order;
+    order = typeof x === "function" ? x : d3_layout_stackOrders[x];
+    return stack;
+  };
+
+  stack.offset = function(x) {
+    if (!arguments.length) return offset;
+    offset = typeof x === "function" ? x : d3_layout_stackOffsets[x];
+    return stack;
+  };
+
+  stack.x = function(z) {
+    if (!arguments.length) return x;
+    x = z;
+    return stack;
+  };
+
+  stack.y = function(z) {
+    if (!arguments.length) return y;
+    y = z;
+    return stack;
+  };
+
+  stack.out = function(z) {
+    if (!arguments.length) return out;
+    out = z;
+    return stack;
+  };
+
+  return stack;
+}
+
+function d3_layout_stackX(d) {
+  return d.x;
+}
+
+function d3_layout_stackY(d) {
+  return d.y;
+}
+
+function d3_layout_stackOut(d, y0, y) {
+  d.y0 = y0;
+  d.y = y;
+}
+
+var d3_layout_stackOrders = {
+
+  "inside-out": function(data) {
+    var n = data.length,
+        i,
+        j,
+        max = data.map(d3_layout_stackMaxIndex),
+        sums = data.map(d3_layout_stackReduceSum),
+        index = d3.range(n).sort(function(a, b) { return max[a] - max[b]; }),
+        top = 0,
+        bottom = 0,
+        tops = [],
+        bottoms = [];
+    for (i = 0; i < n; ++i) {
+      j = index[i];
+      if (top < bottom) {
+        top += sums[j];
+        tops.push(j);
+      } else {
+        bottom += sums[j];
+        bottoms.push(j);
+      }
+    }
+    return bottoms.reverse().concat(tops);
+  },
+
+  "reverse": function(data) {
+    return d3.range(data.length).reverse();
+  },
+
+  "default": function(data) {
+    return d3.range(data.length);
+  }
+
+};
+
+var d3_layout_stackOffsets = {
+
+  "silhouette": function(data) {
+    var n = data.length,
+        m = data[0].length,
+        sums = [],
+        max = 0,
+        i,
+        j,
+        o,
+        y0 = [];
+    for (j = 0; j < m; ++j) {
+      for (i = 0, o = 0; i < n; i++) o += data[i][j][1];
+      if (o > max) max = o;
+      sums.push(o);
+    }
+    for (j = 0; j < m; ++j) {
+      y0[j] = (max - sums[j]) / 2;
+    }
+    return y0;
+  },
+
+  "wiggle": function(data) {
+    var n = data.length,
+        x = data[0],
+        m = x.length,
+        max = 0,
+        i,
+        j,
+        k,
+        s1,
+        s2,
+        s3,
+        dx,
+        o,
+        o0,
+        y0 = [];
+    y0[0] = o = o0 = 0;
+    for (j = 1; j < m; ++j) {
+      for (i = 0, s1 = 0; i < n; ++i) s1 += data[i][j][1];
+      for (i = 0, s2 = 0, dx = x[j][0] - x[j - 1][0]; i < n; ++i) {
+        for (k = 0, s3 = (data[i][j][1] - data[i][j - 1][1]) / (2 * dx); k < i; ++k) {
+          s3 += (data[k][j][1] - data[k][j - 1][1]) / dx;
+        }
+        s2 += s3 * data[i][j][1];
+      }
+      y0[j] = o -= s1 ? s2 / s1 * dx : 0;
+      if (o < o0) o0 = o;
+    }
+    for (j = 0; j < m; ++j) y0[j] -= o0;
+    return y0;
+  },
+
+  "expand": function(data) {
+    var n = data.length,
+        m = data[0].length,
+        k = 1 / n,
+        i,
+        j,
+        o,
+        y0 = [];
+    for (j = 0; j < m; ++j) {
+      for (i = 0, o = 0; i < n; i++) o += data[i][j][1];
+      if (o) for (i = 0; i < n; i++) data[i][j][1] /= o;
+      else for (i = 0; i < n; i++) data[i][j][1] = k;
+    }
+    for (j = 0; j < m; ++j) y0[j] = 0;
+    return y0;
+  },
+
+  "zero": function(data) {
+    var j = -1,
+        m = data[0].length,
+        y0 = [];
+    while (++j < m) y0[j] = 0;
+    return y0;
+  }
+
+};
+
+function d3_layout_stackMaxIndex(array) {
+  var i = 1,
+      j = 0,
+      v = array[0][1],
+      k,
+      n = array.length;
+  for (; i < n; ++i) {
+    if ((k = array[i][1]) > v) {
+      j = i;
+      v = k;
+    }
+  }
+  return j;
+}
+
+function d3_layout_stackReduceSum(d) {
+  return d.reduce(d3_layout_stackSum, 0);
+}
+
+function d3_layout_stackSum(p, d) {
+  return p + d[1];
+}