bar transitions: support object constancy

src/traces/bar/plot.js

@@ -31,6 +31,13 @@ var appendArrayPointValue = require('../../components/fx/helpers').appendArrayPo
 // padding in pixels around text
 var TEXTPAD = 3;
 
+function keyFunc(d) {return d.id;}
+function getKeyFunc(trace) {
+    if(trace.ids) {
+        return keyFunc;
+    }
+}
+
 function dirSign(a, b) {
     return (a < b) ? 1 : -1;
 }
@@ -103,7 +110,8 @@ function plot(gd, plotinfo, cdModule, traceLayer, opts, makeOnCompleteCallback)
 
         var pointGroup = Lib.ensureSingle(plotGroup, 'g', 'points');
 
-        var bars = pointGroup.selectAll('g.point').data(Lib.identity);
+        var keyFunc = getKeyFunc(trace);
+        var bars = pointGroup.selectAll('g.point').data(Lib.identity, keyFunc);
 
         bars.enter().append('g')
             .classed('point', true);

test/image/mocks/animation_bar.json

@@ -3,6 +3,7 @@
     "type": "bar",
     "x": ["A", "B", "C"],
     "y": [24, 5, 8],
+    "ids": ["A", "B", "C"],
     "error_y": {"array": [3, 2, 1]}
     }],
   "layout": {
@@ -17,6 +18,7 @@
       {"data": [{"width": 0.25}]},
       {"data": [{"marker": {"line": {"width": 10}}}]},
       {"data": [{"marker": {"line": {"color": ["orange", "yellow", "blue"]}}}]},
+      {"data": [{"ids": ["B", "C", "A"]}]},
       {"layout": {"yaxis": {"range": [0, 20]}}}
     ]
 }

test/jasmine/assets/check_transitions.js

@@ -89,7 +89,10 @@ function assert(test) {
     var cur = [];
     d3.selectAll(test[1]).each(function(d, i) {
         if(test[2] === 'style') cur[i] = this.style[test[3]];
-        if(test[2] === 'attr') cur[i] = d3.select(this).attr(test[3]);
+        else if(test[2] === 'attr') cur[i] = d3.select(this).attr(test[3]);
+        else if(test[2] === 'datum') {
+            cur[i] = d3.select(this).datum()[test[3]];
+        }
     });
     switch(test[3]) {
         case 'd':

test/jasmine/tests/bar_test.js

@@ -2683,4 +2683,45 @@ describe('bar tweening', function() {
           .catch(failTest)
           .then(done);
     });
+
+    it('for bar positions during object-constancy transitions', function(done) {
+        var _mock = {
+            data: [{
+                type: 'bar',
+                ids: ['A', 'B', 'C'],
+                x: ['A', 'B', 'C'],
+                text: ['A', 'B', 'C'],
+                textposition: 'inside',
+                y: [24, 5, 8],
+                error_y: {'array': [3, 2, 1]},
+                marker: {color: ['red', 'green', 'blue']}
+            }]
+        };
+
+        var nextFrame = { data: [{ ids: ['B', 'C', 'A'] }] };
+
+        var tests = [
+            [0, '.point path', 'datum', 'id', ['A', 'B', 'C']],
+            [0, '.point path', 'style', 'fill', ['rgb(255, 0, 0)', 'rgb(0, 128, 0)', 'rgb(0, 0, 255)']],
+            [0, '.point path', 'attr', 'd', ['M18,270V42H162V270Z', 'M198,270V222.5H342V270Z', 'M378,270V194H522V270Z']],
+            [0, 'text.bartext', 'attr', 'transform', ['translate(90 56)', 'translate(270 236.5)', 'translate(450 208)']],
+            [0, 'path.yerror', 'attr', 'd', ['M86,14h8m-4,0V71m-4,0h8', 'M266,204h8m-4,0V242m-4,0h8', 'M446,185h8m-4,0V204m-4,0h8']],
+
+            [250, '.point path', 'datum', 'id', ['A', 'B', 'C']],
+            [250, '.point path', 'style', 'fill', ['rgb(128, 0, 128)', 'rgb(128, 64, 0)', 'rgb(0, 64, 128)']],
+            [250, '.point path', 'attr', 'd', ['M198,270V118H342V270Z', 'M108,270V132H252V270Z', 'M288,270V208H432V270Z']],
+            [250, 'text.bartext', 'attr', 'transform', ['translate(269.7890625 134)', 'translate(179.5859375 148.25)', 'translate(359.578125 224.25)']],
+            [250, 'path.yerror', 'attr', 'd', ['M266,99h8m-4,0V137m-4,0h8', 'M176,109h8m-4,0V156m-4,0h8', 'M356,194h8m-4,0V223m-4,0h8']],
+
+            [500, '.point path', 'datum', 'id', ['A', 'B', 'C']],
+            [500, '.point path', 'style', 'fill', ['rgb(0, 0, 255)', 'rgb(255, 0, 0)', 'rgb(0, 128, 0)']],
+            [500, '.point path', 'attr', 'd', ['M378,270V194H522V270Z', 'M18,270V42H162V270Z', 'M198,270V223H342V270Z']],
+            [500, 'text.bartext', 'attr', 'transform', ['translate(450 208)', 'translate(90 56)', 'translate(270 236.5)']],
+            [500, 'path.yerror', 'attr', 'd', ['M446,185h8m-4,0V204m-4,0h8', 'M86,14h8m-4,0V71m-4,0h8', 'M266,204h8m-4,0V242m-4,0h8']]
+        ];
+
+        checkTransition(gd, _mock, nextFrame, transitionOpts, tests)
+            .catch(failTest)
+            .then(done);
+    });
 });