implement legendrank

Author: archmoj

src/components/legend/get_legend_data.js

@@ -71,21 +71,33 @@ module.exports = function getLegendData(calcdata, opts) {
     var ltraces;
     var legendData;
 
+    // sort considering trace.legendrank and legend.traceorder
+    var dir = helpers.isReversed(opts) ? -1 : 1;
+    var orderFn = function(a, b) {
+        var A = a[0].trace;
+        var B = b[0].trace;
+        var delta = A.legendrank - B.legendrank;
+        if(!delta) delta = A.index - B.index;
+
+        return dir * delta;
+    };
+
     if(hasOneNonBlankGroup && helpers.isGrouped(opts)) {
         legendData = new Array(lgroupsLength);
 
         for(i = 0; i < lgroupsLength; i++) {
             ltraces = lgroupToTraces[lgroups[i]];
-            legendData[i] = helpers.isReversed(opts) ? ltraces.reverse() : ltraces;
+            legendData[i] = ltraces.sort(orderFn);
         }
     } else {
         // collapse all groups into one if all groups are blank
-        legendData = [new Array(lgroupsLength)];
-
+        legendData = [[]];
         for(i = 0; i < lgroupsLength; i++) {
-            ltraces = lgroupToTraces[lgroups[i]][0];
-            legendData[0][helpers.isReversed(opts) ? lgroupsLength - i - 1 : i] = ltraces;
+            legendData[0].push(
+                lgroupToTraces[lgroups[i]][0]
+            );
         }
+        legendData[0] = legendData[0].sort(orderFn);
         lgroupsLength = 1;
     }
 

src/plots/attributes.js

@@ -41,6 +41,16 @@ module.exports = {
             'when toggling legend items.'
         ].join(' ')
     },
+    legendrank: {
+        valType: 'number',
+        dflt: 1000,
+        editType: 'style',
+        description: [
+            'Sets the legend rank for this trace.',
+            'Items with smaller ranks would be presented on top/left side while',
+            'with `*reversed* `legend.traceorder` they would be on bottom/right side.'
+        ].join(' ')
+    },
     opacity: {
         valType: 'number',
         min: 0,

src/plots/plots.js

@@ -1309,6 +1309,7 @@ plots.supplyTraceDefaults = function(traceIn, traceOut, colorIndex, layout, trac
             );
 
             coerce('legendgroup');
+            coerce('legendrank');
 
             traceOut._dfltShowLegend = true;
         } else {

src/traces/parcats/attributes.js

@@ -198,6 +198,7 @@ module.exports = {
     hoverlabel: undefined,
     ids: undefined,
     legendgroup: undefined,
+    legendrank: undefined,
     opacity: undefined,
     selectedpoints: undefined,
     showlegend: undefined