sort categories by values: add support for histogram2dcontour

Author: antoinerg

Diff for: src/plots/plots.js

@@ -2861,6 +2861,31 @@ var sortAxisCategoriesByValueRegex = /(value|sum|min|max) (ascending|descending)
 function sortAxisCategoriesByValue(axList, gd) {
     var affectedTraces = [];
     var i, j, k, l, o;
+
+    function zMapCategory(type, ax, value) {
+        var axLetter = ax._id.charAt(0);
+        if(type === 'histogram2dcontour') {
+            var counterAxLetter = ax._counterAxes[0];
+            var counterAx = axisIDs.getFromId(gd, counterAxLetter);
+
+            var xCategorical = axLetter === 'x' || (counterAxLetter === 'x' && counterAx.type === 'category');
+            var yCategorical = axLetter === 'y' || (counterAxLetter === 'y' && counterAx.type === 'category');
+
+            return function(o, l) {
+                if(o === 0 || l === 0) return -1; // Skip first row and column
+                if(xCategorical && o === value[l].length - 1) return -1;
+                if(yCategorical && l === value.length - 1) return -1;
+
+                var catIndex = axLetter === 'y' ? l : o;
+                return catIndex - 1;
+            };
+        } else {
+            return function(o, l) {
+                return axLetter === 'y' ? l : o;
+            };
+        }
+    }
+
     for(i = 0; i < axList.length; i++) {
         var ax = axList[i];
         if(ax.type !== 'category') continue;
@@ -2950,11 +2975,12 @@ function sortAxisCategoriesByValue(axList, gd) {
                         // If 2dMap, collect values in `z`
                         if(cdi.hasOwnProperty('z')) {
                             value = cdi.z;
+                            var mapping = zMapCategory(fullTrace.type, ax, value);
 
                             for(l = 0; l < value.length; l++) {
                                 for(o = 0; o < value[l].length; o++) {
-                                    catIndex = ax._id.charAt(0) === 'y' ? l : o;
-                                    categoriesValue[catIndex][1].push(value[l][o]);
+                                    catIndex = mapping(o, l);
+                                    if(catIndex + 1) categoriesValue[catIndex][1].push(value[l][o]);
                                 }
                             }
                         } else {

Diff for: test/jasmine/tests/calcdata_test.js

@@ -885,9 +885,7 @@ describe('calculated data and points', function() {
             });
 
             // excludedTraces are traces that do not support sorting by value
-            var excludedTraces = [ 'carpet', 'contourcarpet',
-                // TODO: add support for the following
-                'histogram2dcontour'];
+            var excludedTraces = [ 'carpet', 'contourcarpet'];
 
             var supportedCartesianTraces = cartesianTraces.filter(function(t) {
                 if(excludedTraces.indexOf(t.type) === -1) return true;
@@ -975,12 +973,12 @@ describe('calculated data and points', function() {
                         Plotly.newPlot(gd, mock)
                         .then(function(gd) {
                             var agg = gd._fullLayout[trace.type === 'splom' ? 'xaxis' : axName]._categoriesAggregatedValue.sort(function(a, b) {
-                                return a[0] > b[0];
+                                return a[0] > b[0] ? 1 : -1;
                             });
                             expect(agg).toEqual(expectedAgg, 'wrong aggregation for ' + axName);
 
                             if(finalOrder) {
-                                expect(gd._fullLayout[trace.type === 'splom' ? 'xaxis' : axName]._categories).toEqual(finalOrder, 'for trace ' + trace.type);
+                                expect(gd._fullLayout[trace.type === 'splom' ? 'xaxis' : axName]._categories).toEqual(finalOrder, 'wrong order');
                             }
                         })
                         .catch(failTest)