move the logic above firstTick so that we know ax.dtick by that time

Author: archmoj

src/plots/cartesian/axes.js

@@ -613,19 +613,6 @@ axes.calcTicks = function calcTicks(ax, opts) {
     var minRange = Math.min(rng[0], rng[1]);
     var maxRange = Math.max(rng[0], rng[1]);
 
-    // find the first tick
-    ax._tmin = axes.tickFirst(ax, opts);
-
-    // No visible ticks? Quit.
-    // I've only seen this on category axes with all categories off the edge.
-    if((ax._tmin < startTick) !== axrev) return [];
-
-    // return the full set of tick vals
-    if(ax.type === 'category' || ax.type === 'multicategory') {
-        endTick = (axrev) ? Math.max(-0.5, endTick) :
-            Math.min(ax._categories.length - 0.5, endTick);
-    }
-
     var isDLog = (ax.type === 'log') && !(isNumeric(ax.dtick) || ax.dtick.charAt(0) === 'L');
     var isMDate = (ax.type === 'date') && !(isNumeric(ax.dtick) || ax.dtick.charAt(0) === 'M');
 
@@ -708,6 +695,19 @@ axes.calcTicks = function calcTicks(ax, opts) {
         }
     }
 
+    // find the first tick
+    ax._tmin = axes.tickFirst(ax, opts);
+
+    // No visible ticks? Quit.
+    // I've only seen this on category axes with all categories off the edge.
+    if((ax._tmin < startTick) !== axrev) return [];
+
+    // return the full set of tick vals
+    if(ax.type === 'category' || ax.type === 'multicategory') {
+        endTick = (axrev) ? Math.max(-0.5, endTick) :
+            Math.min(ax._categories.length - 0.5, endTick);
+    }
+
     var x = ax._tmin;
 
     if(ax.rangebreaks && ax._tick0Init !== ax.tick0) {

test/jasmine/tests/axes_test.js

@@ -5684,17 +5684,17 @@ describe('Test axes', function() {
         [
             {
                 range: ['2019-12-10', '2020-01-10'],
-                positions: ['2019-12-16 12:00', '2020-01-10'],
+                positions: ['2019-12-17 12:00', '2020-01-10'],
                 labels: ['2019-Dec', ' ']
             },
             {
                 range: ['2019-12-20', '2020-01-20'],
-                positions: ['2019-12-20', '2020-01-16 12:00'],
+                positions: ['2019-12-20', '2020-01-17 12:00'],
                 labels: [' ', '2020-Jan']
             },
             {
                 range: ['2020-01-20', '2019-12-20'],
-                positions: ['2020-01-20', '2020-01-16 12:00'],
+                positions: ['2020-01-20', '2020-01-17 12:00'],
                 labels: [' ', '2020-Jan']
             }
         ].forEach(function(t) {