toolkit/javascript/d3/src/layout/treemap.js
changeset 47 c0b4a8b5a012
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/toolkit/javascript/d3/src/layout/treemap.js	Thu Apr 10 14:20:23 2014 +0200
@@ -0,0 +1,217 @@
+// Squarified Treemaps by Mark Bruls, Kees Huizing, and Jarke J. van Wijk
+// Modified to support a target aspect ratio by Jeff Heer
+d3.layout.treemap = function() {
+  var hierarchy = d3.layout.hierarchy(),
+      round = Math.round,
+      size = [1, 1], // width, height
+      padding = null,
+      pad = d3_layout_treemapPadNull,
+      sticky = false,
+      stickies,
+      ratio = 0.5 * (1 + Math.sqrt(5)); // golden ratio
+
+  // Compute the area for each child based on value & scale.
+  function scale(children, k) {
+    var i = -1,
+        n = children.length,
+        child,
+        area;
+    while (++i < n) {
+      area = (child = children[i]).value * (k < 0 ? 0 : k);
+      child.area = isNaN(area) || area <= 0 ? 0 : area;
+    }
+  }
+
+  // Recursively arranges the specified node's children into squarified rows.
+  function squarify(node) {
+    var children = node.children;
+    if (children && children.length) {
+      var rect = pad(node),
+          row = [],
+          remaining = children.slice(), // copy-on-write
+          child,
+          best = Infinity, // the best row score so far
+          score, // the current row score
+          u = Math.min(rect.dx, rect.dy), // initial orientation
+          n;
+      scale(remaining, rect.dx * rect.dy / node.value);
+      row.area = 0;
+      while ((n = remaining.length) > 0) {
+        row.push(child = remaining[n - 1]);
+        row.area += child.area;
+        if ((score = worst(row, u)) <= best) { // continue with this orientation
+          remaining.pop();
+          best = score;
+        } else { // abort, and try a different orientation
+          row.area -= row.pop().area;
+          position(row, u, rect, false);
+          u = Math.min(rect.dx, rect.dy);
+          row.length = row.area = 0;
+          best = Infinity;
+        }
+      }
+      if (row.length) {
+        position(row, u, rect, true);
+        row.length = row.area = 0;
+      }
+      children.forEach(squarify);
+    }
+  }
+
+  // Recursively resizes the specified node's children into existing rows.
+  // Preserves the existing layout!
+  function stickify(node) {
+    var children = node.children;
+    if (children && children.length) {
+      var rect = pad(node),
+          remaining = children.slice(), // copy-on-write
+          child,
+          row = [];
+      scale(remaining, rect.dx * rect.dy / node.value);
+      row.area = 0;
+      while (child = remaining.pop()) {
+        row.push(child);
+        row.area += child.area;
+        if (child.z != null) {
+          position(row, child.z ? rect.dx : rect.dy, rect, !remaining.length);
+          row.length = row.area = 0;
+        }
+      }
+      children.forEach(stickify);
+    }
+  }
+
+  // Computes the score for the specified row, as the worst aspect ratio.
+  function worst(row, u) {
+    var s = row.area,
+        r,
+        rmax = 0,
+        rmin = Infinity,
+        i = -1,
+        n = row.length;
+    while (++i < n) {
+      if (!(r = row[i].area)) continue;
+      if (r < rmin) rmin = r;
+      if (r > rmax) rmax = r;
+    }
+    s *= s;
+    u *= u;
+    return s
+        ? Math.max((u * rmax * ratio) / s, s / (u * rmin * ratio))
+        : Infinity;
+  }
+
+  // Positions the specified row of nodes. Modifies `rect`.
+  function position(row, u, rect, flush) {
+    var i = -1,
+        n = row.length,
+        x = rect.x,
+        y = rect.y,
+        v = u ? round(row.area / u) : 0,
+        o;
+    if (u == rect.dx) { // horizontal subdivision
+      if (flush || v > rect.dy) v = v ? rect.dy : 0; // over+underflow
+      while (++i < n) {
+        o = row[i];
+        o.x = x;
+        o.y = y;
+        o.dy = v;
+        x += o.dx = v ? round(o.area / v) : 0;
+      }
+      o.z = true;
+      o.dx += rect.x + rect.dx - x; // rounding error
+      rect.y += v;
+      rect.dy -= v;
+    } else { // vertical subdivision
+      if (flush || v > rect.dx) v = v ? rect.dx : 0; // over+underflow
+      while (++i < n) {
+        o = row[i];
+        o.x = x;
+        o.y = y;
+        o.dx = v;
+        y += o.dy = v ? round(o.area / v) : 0;
+      }
+      o.z = false;
+      o.dy += rect.y + rect.dy - y; // rounding error
+      rect.x += v;
+      rect.dx -= v;
+    }
+  }
+
+  function treemap(d) {
+    var nodes = stickies || hierarchy(d),
+        root = nodes[0];
+    root.x = 0;
+    root.y = 0;
+    root.dx = size[0];
+    root.dy = size[1];
+    if (stickies) hierarchy.revalue(root);
+    scale([root], root.dx * root.dy / root.value);
+    (stickies ? stickify : squarify)(root);
+    if (sticky) stickies = nodes;
+    return nodes;
+  }
+
+  treemap.size = function(x) {
+    if (!arguments.length) return size;
+    size = x;
+    return treemap;
+  };
+
+  treemap.padding = function(x) {
+    if (!arguments.length) return padding;
+
+    function padFunction(node) {
+      var p = x.call(treemap, node, node.depth);
+      return p == null
+          ? d3_layout_treemapPadNull(node)
+          : d3_layout_treemapPad(node, typeof p === "number" ? [p, p, p, p] : p);
+    }
+
+    function padConstant(node) {
+      return d3_layout_treemapPad(node, x);
+    }
+
+    var type;
+    pad = (padding = x) == null ? d3_layout_treemapPadNull
+        : (type = typeof x) === "function" ? padFunction
+        : type === "number" ? (x = [x, x, x, x], padConstant)
+        : padConstant;
+    return treemap;
+  };
+
+  treemap.round = function(x) {
+    if (!arguments.length) return round != Number;
+    round = x ? Math.round : Number;
+    return treemap;
+  };
+
+  treemap.sticky = function(x) {
+    if (!arguments.length) return sticky;
+    sticky = x;
+    stickies = null;
+    return treemap;
+  };
+
+  treemap.ratio = function(x) {
+    if (!arguments.length) return ratio;
+    ratio = x;
+    return treemap;
+  };
+
+  return d3_layout_hierarchyRebind(treemap, hierarchy);
+};
+
+function d3_layout_treemapPadNull(node) {
+  return {x: node.x, y: node.y, dx: node.dx, dy: node.dy};
+}
+
+function d3_layout_treemapPad(node, padding) {
+  var x = node.x + padding[3],
+      y = node.y + padding[0],
+      dx = node.dx - padding[1] - padding[3],
+      dy = node.dy - padding[0] - padding[2];
+  if (dx < 0) { x += dx / 2; dx = 0; }
+  if (dy < 0) { y += dy / 2; dy = 0; }
+  return {x: x, y: y, dx: dx, dy: dy};
+}