Treat missing intersection areas as disjoint

Fix issue #42, detect missing
pairwise intersection areas and add them before optimizing

package.json

@@ -1,12 +1,36 @@
 {
   "name": "venn.js",
-  "version": "0.2.0",
-  "author": "Ben Frederickson",
+  "version": "0.2.1",
+  "author": "Ben Frederickson <ben@benfrederickson.com> (http:/www.benfrederickson.com)",
+  "files": [
+    "venn.min.js",
+    "venn.js"
+  ],
+  "url": "https://github.com/benfred/venn.js/issues",
   "devDependencies": {
     "grunt": "~0.4.5",
     "grunt-contrib-uglify": "~0.9.1",
     "grunt-contrib-concat": "~0.5.1",
     "grunt-contrib-qunit": "~0.7.0",
     "grunt-contrib-jshint": "~0.11.2"
-  }
+  },
+  "description": "Area Proportional Venn and Euler Diagrams",
+  "main": "venn.js",
+  "directories": {
+    "example": "examples",
+    "test": "tests"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/benfred/venn.js.git"
+  },
+  "keywords": [
+    "Venn",
+    "Euler"
+  ],
+  "license": "MIT",
+  "bugs": {
+    "url": "https://github.com/benfred/venn.js/issues"
+  },
+  "homepage": "https://github.com/benfred/venn.js"
 }

src/layout.js

@@ -10,6 +10,9 @@
         var initialLayout = parameters.initialLayout || venn.bestInitialLayout;
         var fmin = parameters.fmin || venn.fmin;
 
+        // add in missing pairwise areas as having 0 size
+        areas = addMissingAreas(areas);
+
         // initial layout is done greedily
         var circles = initialLayout(areas);
 
@@ -68,6 +71,41 @@
         }, 0, r1 + r2);
     };
 
+    /** Missing pair-wise intersection area data can cause problems:
+     treating as an unknown means that sets will be laid out overlapping,
+     which isn't what people expect. To reflect that we want disjoint sets
+     here, set the overlap to 0 for all missing pairwise set intersections */
+    function addMissingAreas(areas) {
+        areas = areas.slice();
+
+        // two circle intersections that aren't defined
+        var ids = [], pairs = {}, i, j, a, b;
+        for (i = 0; i < areas.length; ++i) {
+            var area = areas[i];
+            if (area.sets.length == 1) {
+                ids.push(area.sets[0]);
+            } else if (area.sets.length == 2) {
+                a = area.sets[0];
+                b = area.sets[1];
+                pairs[[a, b]] = true;
+                pairs[[b, a]] = true;
+            }
+        }
+        ids.sort(function(a, b) { return a > b; });
+
+        for (i = 0; i < ids.length; ++i) {
+            a = ids[i];
+            for (j = i + 1; j < ids.length; ++j) {
+                b = ids[j];
+                if (!([a, b] in pairs)) {
+                    areas.push({'sets': [a, b],
+                                'size': 0});
+                }
+            }
+        }
+        return areas;
+    }
+
     /// Returns two matrices, one of the euclidean distances between the sets
     /// and the other indicating if there are subset or disjoint set relationships
     venn.getDistanceMatrices = function(areas, sets, setids) {
@@ -296,7 +334,8 @@
             overlap.sort(sortOrder);
 
             if (overlap.length === 0) {
-                throw "Need overlap information for set " + JSON.stringify( set );
+                // this shouldn't happen anymore with addMissingAreas
+                throw "ERROR: missing pairwise overlap information";
             }
 
             var points = [];

venn.js

@@ -429,6 +429,9 @@ var venn = venn || {'version' : '0.2'};
         var initialLayout = parameters.initialLayout || venn.bestInitialLayout;
         var fmin = parameters.fmin || venn.fmin;
 
+        // add in missing pairwise areas as having 0 size
+        areas = addMissingAreas(areas);
+
         // initial layout is done greedily
         var circles = initialLayout(areas);
 
@@ -487,6 +490,41 @@ var venn = venn || {'version' : '0.2'};
         }, 0, r1 + r2);
     };
 
+    /** Missing pair-wise intersection area data can cause problems:
+     treating as an unknown means that sets will be laid out overlapping,
+     which isn't what people expect. To reflect that we want disjoint sets
+     here, set the overlap to 0 for all missing pairwise set intersections */
+    function addMissingAreas(areas) {
+        areas = areas.slice();
+
+        // two circle intersections that aren't defined
+        var ids = [], pairs = {}, i, j, a, b;
+        for (i = 0; i < areas.length; ++i) {
+            var area = areas[i];
+            if (area.sets.length == 1) {
+                ids.push(area.sets[0]);
+            } else if (area.sets.length == 2) {
+                a = area.sets[0];
+                b = area.sets[1];
+                pairs[[a, b]] = true;
+                pairs[[b, a]] = true;
+            }
+        }
+        ids.sort(function(a, b) { return a > b; });
+
+        for (i = 0; i < ids.length; ++i) {
+            a = ids[i];
+            for (j = i + 1; j < ids.length; ++j) {
+                b = ids[j];
+                if (!([a, b] in pairs)) {
+                    areas.push({'sets': [a, b],
+                                'size': 0});
+                }
+            }
+        }
+        return areas;
+    }
+
     /// Returns two matrices, one of the euclidean distances between the sets
     /// and the other indicating if there are subset or disjoint set relationships
     venn.getDistanceMatrices = function(areas, sets, setids) {
@@ -715,7 +753,8 @@ var venn = venn || {'version' : '0.2'};
             overlap.sort(sortOrder);
 
             if (overlap.length === 0) {
-                throw "Need overlap information for set " + JSON.stringify( set );
+                // this shouldn't happen anymore with addMissingAreas
+                throw "ERROR: missing pairwise overlap information";
             }
 
             var points = [];