Merge pull request #4662 from plotly/fix-4648

histogram: in hover labels, harmonize start/end values of shared bins

Author: antoinerg

src/traces/bar/cross_trace_calc.js

@@ -47,6 +47,14 @@ function crossTraceCalc(gd, plotinfo) {
             } else {
                 calcTracesVert.push(calcTraces[i]);
             }
+
+            if(fullTrace._computePh) {
+                var cd = gd.calcdata[i];
+                for(var j = 0; j < cd.length; j++) {
+                    if(typeof cd[j].ph0 === 'function') cd[j].ph0 = cd[j].ph0();
+                    if(typeof cd[j].ph1 === 'function') cd[j].ph1 = cd[j].ph1();
+                }
+            }
         }
     }
 

src/traces/histogram/calc.js

@@ -102,12 +102,21 @@ function calc(gd, trace) {
         };
     }
 
+    // stash left and right gaps by group
+    if(!gd._fullLayout._roundFnOpts) gd._fullLayout._roundFnOpts = {};
+    var groupName = trace['_' + mainData + 'bingroup'];
+    var roundFnOpts = {leftGap: Infinity, rightGap: Infinity};
+    if(groupName) {
+        if(!gd._fullLayout._roundFnOpts[groupName]) gd._fullLayout._roundFnOpts[groupName] = roundFnOpts;
+        roundFnOpts = gd._fullLayout._roundFnOpts[groupName];
+    }
+
     // bin the data
     // and make histogram-specific pt-number-to-cd-index map object
     var nMax = size.length;
     var uniqueValsPerBin = true;
-    var leftGap = Infinity;
-    var rightGap = Infinity;
+    var leftGap = roundFnOpts.leftGap;
+    var rightGap = roundFnOpts.rightGap;
     var ptNumber2cdIndex = {};
     for(i = 0; i < pos0.length; i++) {
         var posi = pos0[i];
@@ -124,10 +133,21 @@ function calc(gd, trace) {
             rightGap = Math.min(rightGap, binEdges[n + 1] - posi);
         }
     }
+    roundFnOpts.leftGap = leftGap;
+    roundFnOpts.rightGap = rightGap;
 
     var roundFn;
     if(!uniqueValsPerBin) {
-        roundFn = getBinSpanLabelRound(leftGap, rightGap, binEdges, pa, calendar);
+        roundFn = function(v, isRightEdge) {
+            return function() {
+                var roundFnOpts = gd._fullLayout._roundFnOpts[groupName];
+                return getBinSpanLabelRound(
+                    roundFnOpts.leftGap,
+                    roundFnOpts.rightGap,
+                    binEdges, pa, calendar
+                )(v, isRightEdge);
+            };
+        };
     }
 
     // average and/or normalize the data, if needed
@@ -173,6 +193,8 @@ function calc(gd, trace) {
                 if(uniqueValsPerBin) {
                     cdi.ph0 = cdi.ph1 = (inputPoints[i].length) ? pos0[inputPoints[i][0]] : pos[i];
                 } else {
+                    // Defer evaluation of ph(0|1) in crossTraceCalc
+                    trace._computePh = true;
                     cdi.ph0 = roundFn(binEdges[i]);
                     cdi.ph1 = roundFn(binEdges[i + 1], true);
                 }

test/jasmine/tests/histogram_test.js

@@ -585,6 +585,7 @@ describe('Test histogram', function() {
             // even though -0 === 0
             out.forEach(function(cdi) {
                 for(var key in cdi) {
+                    if(typeof cdi[key] === 'function') cdi[key] = cdi[key]();
                     if(cdi[key] === 0) cdi[key] = 0;
                 }
             });
@@ -861,6 +862,23 @@ describe('Test histogram', function() {
             expect(calcPositions(trace2, [trace1])).toEqual([5, 7]);
         });
 
+        it('harmonizes start/end value of bins when all traces are autobinned', function(done) {
+            var mock = require('@mocks/histogram_overlay-bingroup');
+            var gd = createGraphDiv();
+            Plotly.newPlot(gd, mock)
+                .then(function(gd) {
+                    destroyGraphDiv();
+                    var cd0 = gd.calcdata[0];
+                    var cd1 = gd.calcdata[1];
+                    for(var i = 0; i < cd0.length && i < cd1.length; i++) {
+                        expect(cd0[i].ph0).toBe(cd1[i].ph0);
+                        expect(cd0[i].ph1).toBe(cd1[i].ph1);
+                    }
+                })
+                .catch(failTest)
+                .then(done);
+        });
+
         it('autobins all data as one', function() {
             // all integers, so all autobins should get shifted to start 0.5 lower
             // than they otherwise would.