ensures that padded space is not larger than figure

build/d3-sankey.js

@@ -0,0 +1,321 @@
+// https://github.com/d3/d3-sankey Version 0.5.0. Copyright 2018 Mike Bostock.
+(function (global, factory) {
+	typeof exports === 'object' && typeof module !== 'undefined' ? factory(exports, require('d3-array'), require('d3-collection'), require('d3-interpolate')) :
+	typeof define === 'function' && define.amd ? define(['exports', 'd3-array', 'd3-collection', 'd3-interpolate'], factory) :
+	(factory((global.d3 = global.d3 || {}),global.d3,global.d3,global.d3));
+}(this, (function (exports,d3Array,d3Collection,d3Interpolate) { 'use strict';
+
+var sankey = function() {
+  var sankey = {},
+      nodeWidth = 24,
+      nodePadding = 8,
+      size = [1, 1],
+      nodes = [],
+      links = [],
+      maxPaddedSpace = 2 / 3; // Defined as a fraction of the total available space
+
+  sankey.nodeWidth = function(_) {
+    if (!arguments.length) return nodeWidth;
+    nodeWidth = +_;
+    return sankey;
+  };
+
+  sankey.nodePadding = function(_) {
+    if (!arguments.length) return nodePadding;
+    nodePadding = +_;
+    return sankey;
+  };
+
+  sankey.nodes = function(_) {
+    if (!arguments.length) return nodes;
+    nodes = _;
+    return sankey;
+  };
+
+  sankey.links = function(_) {
+    if (!arguments.length) return links;
+    links = _;
+    return sankey;
+  };
+
+  sankey.size = function(_) {
+    if (!arguments.length) return size;
+    size = _;
+    return sankey;
+  };
+
+  sankey.layout = function(iterations) {
+    computeNodeLinks();
+    computeNodeValues();
+    computeNodeBreadths();
+    computeNodeDepths(iterations);
+    computeLinkDepths();
+    return sankey;
+  };
+
+  sankey.relayout = function() {
+    computeLinkDepths();
+    return sankey;
+  };
+
+  sankey.link = function() {
+    var curvature = .5;
+
+    function link(d) {
+      var x0 = d.source.x + d.source.dx,
+          x1 = d.target.x,
+          xi = d3Interpolate.interpolateNumber(x0, x1),
+          x2 = xi(curvature),
+          x3 = xi(1 - curvature),
+          y0a = d.source.y + d.sy,
+          y0b = y0a + d.dy,
+          y1a = d.target.y + d.ty,
+          y1b = y1a + d.dy;
+      return "M" + x0 + "," + y0a
+           + "C" + x2 + "," + y0a
+           + " " + x3 + "," + y1a
+           + " " + x1 + "," + y1a
+           + "L" + x1 + "," + y1b
+           + "C" + x3 + "," + y1b
+           + " " + x2 + "," + y0b
+           + " " + x0 + "," + y0b
+           + "Z";
+    }
+
+    link.curvature = function(_) {
+      if (!arguments.length) return curvature;
+      curvature = +_;
+      return link;
+    };
+
+    return link;
+  };
+
+  // Populate the sourceLinks and targetLinks for each node.
+  // Also, if the source and target are not objects, assume they are indices.
+  function computeNodeLinks() {
+    nodes.forEach(function(node) {
+      node.sourceLinks = [];
+      node.targetLinks = [];
+    });
+    links.forEach(function(link, i) {
+      var source = link.source,
+          target = link.target;
+      if (typeof source === "number") source = link.source = nodes[link.source];
+      if (typeof target === "number") target = link.target = nodes[link.target];
+      link.originalIndex = i;
+      source.sourceLinks.push(link);
+      target.targetLinks.push(link);
+    });
+  }
+
+  // Compute the value (size) of each node by summing the associated links.
+  function computeNodeValues() {
+    nodes.forEach(function(node) {
+      node.value = Math.max(
+        d3Array.sum(node.sourceLinks, value),
+        d3Array.sum(node.targetLinks, value)
+      );
+    });
+  }
+
+  // Iteratively assign the breadth (x-position) for each node.
+  // Nodes are assigned the maximum breadth of incoming neighbors plus one;
+  // nodes with no incoming links are assigned breadth zero, while
+  // nodes with no outgoing links are assigned the maximum breadth.
+  function computeNodeBreadths() {
+    var remainingNodes = nodes,
+        nextNodes,
+        x = 0;
+
+    while (remainingNodes.length) {
+      nextNodes = [];
+      remainingNodes.forEach(function(node) {
+        node.x = x;
+        node.dx = nodeWidth;
+        node.sourceLinks.forEach(function(link) {
+          if (nextNodes.indexOf(link.target) < 0) {
+            nextNodes.push(link.target);
+          }
+        });
+      });
+      remainingNodes = nextNodes;
+      ++x;
+    }
+
+    //
+    moveSinksRight(x);
+    scaleNodeBreadths((size[0] - nodeWidth) / (x - 1));
+  }
+
+  // function moveSourcesRight() {
+  //   nodes.forEach(function(node) {
+  //     if (!node.targetLinks.length) {
+  //       node.x = min(node.sourceLinks, function(d) { return d.target.x; }) - 1;
+  //     }
+  //   });
+  // }
+
+  function moveSinksRight(x) {
+    nodes.forEach(function(node) {
+      if (!node.sourceLinks.length) {
+        node.x = x - 1;
+      }
+    });
+  }
+
+  function scaleNodeBreadths(kx) {
+    nodes.forEach(function(node) {
+      node.x *= kx;
+    });
+  }
+
+  function computeNodeDepths(iterations) {
+    var nodesByBreadth = d3Collection.nest()
+        .key(function(d) { return d.x; })
+        .sortKeys(d3Array.ascending)
+        .entries(nodes)
+        .map(function(d) { return d.values; });
+
+    //
+    initializeNodeDepth();
+    resolveCollisions();
+    for (var alpha = 1; iterations > 0; --iterations) {
+      relaxRightToLeft(alpha *= .99);
+      resolveCollisions();
+      relaxLeftToRight(alpha);
+      resolveCollisions();
+    }
+
+    function initializeNodeDepth() {
+      var L = d3Array.max(nodesByBreadth, function(nodes) {
+        return nodes.length;
+      });
+      var maxNodePadding = maxPaddedSpace * size[1] / (L - 1);
+      if(nodePadding > maxNodePadding) nodePadding = maxNodePadding;
+      var ky = d3Array.min(nodesByBreadth, function(nodes) {
+        return (size[1] - (nodes.length - 1) * nodePadding) / d3Array.sum(nodes, value);
+      });
+
+      nodesByBreadth.forEach(function(nodes) {
+        nodes.forEach(function(node, i) {
+          node.y = i;
+          node.dy = node.value * ky;
+        });
+      });
+
+      links.forEach(function(link) {
+        link.dy = link.value * ky;
+      });
+    }
+
+    function relaxLeftToRight(alpha) {
+      nodesByBreadth.forEach(function(nodes) {
+        nodes.forEach(function(node) {
+          if (node.targetLinks.length) {
+            var y = d3Array.sum(node.targetLinks, weightedSource) / d3Array.sum(node.targetLinks, value);
+            node.y += (y - center(node)) * alpha;
+          }
+        });
+      });
+
+      function weightedSource(link) {
+        return center(link.source) * link.value;
+      }
+    }
+
+    function relaxRightToLeft(alpha) {
+      nodesByBreadth.slice().reverse().forEach(function(nodes) {
+        nodes.forEach(function(node) {
+          if (node.sourceLinks.length) {
+            var y = d3Array.sum(node.sourceLinks, weightedTarget) / d3Array.sum(node.sourceLinks, value);
+            node.y += (y - center(node)) * alpha;
+          }
+        });
+      });
+
+      function weightedTarget(link) {
+        return center(link.target) * link.value;
+      }
+    }
+
+    function resolveCollisions() {
+      nodesByBreadth.forEach(function(nodes) {
+        var node,
+            dy,
+            y0 = 0,
+            n = nodes.length,
+            i;
+
+        // Push any overlapping nodes down.
+        nodes.sort(ascendingDepth);
+        for (i = 0; i < n; ++i) {
+          node = nodes[i];
+          dy = y0 - node.y;
+          if (dy > 0) node.y += dy;
+          y0 = node.y + node.dy + nodePadding;
+        }
+
+        // If the bottommost node goes outside the bounds, push it back up.
+        dy = y0 - nodePadding - size[1];
+        if (dy > 0) {
+          y0 = node.y -= dy;
+
+          // Push any overlapping nodes back up.
+          for (i = n - 2; i >= 0; --i) {
+            node = nodes[i];
+            dy = node.y + node.dy + nodePadding - y0;
+            if (dy > 0) node.y -= dy;
+            y0 = node.y;
+          }
+        }
+      });
+    }
+
+    function ascendingDepth(a, b) {
+      return a.y - b.y;
+    }
+  }
+
+  function computeLinkDepths() {
+    nodes.forEach(function(node) {
+      node.sourceLinks.sort(ascendingTargetDepth);
+      node.targetLinks.sort(ascendingSourceDepth);
+    });
+    nodes.forEach(function(node) {
+      var sy = 0, ty = 0;
+      node.sourceLinks.forEach(function(link) {
+        link.sy = sy;
+        sy += link.dy;
+      });
+      node.targetLinks.forEach(function(link) {
+        link.ty = ty;
+        ty += link.dy;
+      });
+    });
+
+    function ascendingSourceDepth(a, b) {
+      return (a.source.y - b.source.y) || (a.originalIndex - b.originalIndex);
+    }
+
+    function ascendingTargetDepth(a, b) {
+      return (a.target.y - b.target.y) || (a.originalIndex - b.originalIndex);
+    }
+  }
+
+  function center(node) {
+    return node.y + node.dy / 2;
+  }
+
+  function value(link) {
+    return link.value;
+  }
+
+  return sankey;
+};
+
+exports.sankey = sankey;
+
+Object.defineProperty(exports, '__esModule', { value: true });
+
+})));

src/sankey.js

@@ -1,4 +1,4 @@
-import {ascending, min, sum} from "d3-array";
+import {ascending, min, sum, max} from "d3-array";
 import {nest} from "d3-collection";
 import {interpolateNumber} from "d3-interpolate";
 
@@ -8,7 +8,8 @@ export default function() {
       nodePadding = 8,
       size = [1, 1],
       nodes = [],
-      links = [];
+      links = [],
+      maxPaddedSpace = 2 / 3; // Defined as a fraction of the total available space
 
   sankey.nodeWidth = function(_) {
     if (!arguments.length) return nodeWidth;
@@ -184,6 +185,11 @@ export default function() {
     }
 
     function initializeNodeDepth() {
+      var L = max(nodesByBreadth, function(nodes) {
+        return nodes.length;
+      });
+      var maxNodePadding = maxPaddedSpace * size[1] / (L - 1);
+      if(nodePadding > maxNodePadding) nodePadding = maxNodePadding;
       var ky = min(nodesByBreadth, function(nodes) {
         return (size[1] - (nodes.length - 1) * nodePadding) / sum(nodes, value);
       });