From f907f2a3f8009f2180d7bcf00bcd31e17c4351f8 Mon Sep 17 00:00:00 2001
From: archmoj <mojtaba@plot.ly>
Date: Wed, 19 Aug 2020 18:38:31 -0400
Subject: [PATCH] revise period lengths on axes with rangebreaks

---
 src/plots/cartesian/axes.js     | 37 ++++++++++++++++++++-------------
 test/jasmine/tests/axes_test.js |  8 ++++---
 2 files changed, 27 insertions(+), 18 deletions(-)

diff --git a/src/plots/cartesian/axes.js b/src/plots/cartesian/axes.js
index ca684db2cf0..cf1dc993f8b 100644
--- a/src/plots/cartesian/axes.js
+++ b/src/plots/cartesian/axes.js
@@ -781,42 +781,49 @@ axes.calcTicks = function calcTicks(ax, opts) {
 
             var A = tickVals[a].value;
             var B = tickVals[b].value;
-
             var actualDelta = Math.abs(B - A);
             var delta = definedDelta || actualDelta;
+            var periodLength = 0;
+
             if(delta >= ONEMINYEAR) {
                 if(actualDelta >= ONEMINYEAR && actualDelta <= ONEMAXYEAR) {
-                    v += actualDelta / 2;
+                    periodLength = actualDelta;
                 } else {
-                    v += ONEAVGYEAR / 2;
+                    periodLength = ONEAVGYEAR;
                 }
             } else if(delta >= ONEMINQUARTER) {
                 if(
                     definedDelta && // case of specified by tickfomat
                     actualDelta >= ONEMINQUARTER && actualDelta <= ONEMAXQUARTER
                 ) {
-                    v += actualDelta / 2;
+                    periodLength = actualDelta;
                 } else {
-                    v += ONEAVGQUARTER / 2;
+                    periodLength = ONEAVGQUARTER;
                 }
             } else if(delta >= ONEMINMONTH) {
                 if(actualDelta >= ONEMINMONTH && actualDelta <= ONEMAXMONTH) {
-                    v += actualDelta / 2;
+                    periodLength = actualDelta;
                 } else {
-                    v += ONEAVGMONTH / 2;
+                    periodLength = ONEAVGMONTH;
                 }
             } else if(delta >= ONEWEEK) {
-                v += ONEWEEK / 2;
-                if(
-                    definedDelta && // case of specified by tickfomat
-                    actualDelta === ONEWEEK && ax._hasDayOfWeekBreaks
-                ) {
-                    v -= ONEDAY; // half of two days which is a good approximation for the number of week-end days
-                }
+                periodLength = ONEWEEK;
             } else if(delta >= ONEDAY) {
-                v += ONEDAY / 2;
+                periodLength = ONEDAY;
             }
 
+            if(ax.rangebreaks) {
+                var nOut = 0;
+                var nAll = 2 * 3 * 5 * 7; // number of samples
+                for(var c = 0; c < nAll; c++) {
+                    var r = c / nAll;
+                    if(ax.maskBreaks(A * (1 - r) + B * r) === BADNUM) nOut++;
+                }
+                periodLength *= 1 - nOut / nAll;
+            }
+
+            v += periodLength / 2;
+
             ticksOut[i].periodX = v;
 
             if(v > maxRange || v < minRange) { // hide label if outside the range
diff --git a/test/jasmine/tests/axes_test.js b/test/jasmine/tests/axes_test.js
index 3d67f7a8e02..d51ab49cfbb 100644
--- a/test/jasmine/tests/axes_test.js
+++ b/test/jasmine/tests/axes_test.js
@@ -5432,9 +5432,11 @@ describe('Test axes', function() {
                 })
                 .then(function() {
                     _assert('', [
-                        '2020-01-01 12:00', '2020-01-08 12:00', '2020-01-15 12:00', '2020-01-22 12:00', '2020-01-29 12:00'
-                    ], [
-                        ['Dec-52', 'Jan-01', 'Jan-02', 'Jan-03', 'Jan-04'],
+                        ['2019-12-31 04:24', '2020-01-08 12:00', '2020-01-15 12:00', '2020-01-22 12:00', '2020-01-29 12:00'],
+                        ['2020-01-01 12:00', '2020-01-08 12:00', '2020-01-15 12:00', '2020-01-22 12:00', '2020-01-29 12:00'],
+                        ['2020-01-01 12:00', '2020-01-08 12:00', '2020-01-15 12:00', '2020-01-22 12:00', '2020-01-29 12:00']
+                    ][i], [
+                        ['', 'Jan-01', 'Jan-02', 'Jan-03', 'Jan-04'],
                         ['Dec-01', 'Jan-02', 'Jan-03', 'Jan-04', 'Jan-05'],
                         ['Dec-52', 'Jan-01', 'Jan-02', 'Jan-03', 'Jan-04']
                     ][i]);