08-27-周三_17-09-29

node_modules/dagre-layout/lib/rank/index.js

@@ -0,0 +1,45 @@
+import { longestPath } from './util'
+import feasibleTree from './feasible-tree'
+import networkSimplex from './network-simplex'
+
+/*
+ * Assigns a rank to each node in the input graph that respects the "minlen"
+ * constraint specified on edges between nodes.
+ *
+ * This basic structure is derived from Gansner, et al., "A Technique for
+ * Drawing Directed Graphs."
+ *
+ * Pre-conditions:
+ *
+ *    1. Graph must be a connected DAG
+ *    2. Graph nodes must be objects
+ *    3. Graph edges must have "weight" and "minlen" attributes
+ *
+ * Post-conditions:
+ *
+ *    1. Graph nodes will have a "rank" attribute based on the results of the
+ *       algorithm. Ranks can start at any index (including negative), we'll
+ *       fix them up later.
+ */
+function rank (g) {
+  switch (g.graph().ranker) {
+    case 'network-simplex': networkSimplexRanker(g); break
+    case 'tight-tree': tightTreeRanker(g); break
+    case 'longest-path': longestPathRanker(g); break
+    default: networkSimplexRanker(g)
+  }
+}
+
+// A fast and simple ranker, but results are far from optimal.
+const longestPathRanker = longestPath
+
+function tightTreeRanker (g) {
+  longestPath(g)
+  feasibleTree(g)
+}
+
+function networkSimplexRanker (g) {
+  networkSimplex(g)
+}
+
+export default rank