introduce new attribute for log axes

Author: archmoj

src/plots/cartesian/layout_attributes.js

@@ -1234,6 +1234,17 @@ module.exports = {
             'Used with `categoryorder`.'
         ].join(' ')
     },
+    loglabels: {
+        valType: 'enumerated',
+        values: ['small digits', 'full value'],
+        dflt: 'small digits',
+        editType: 'calc',
+        description: [
+            'Determines how minor log labels are displayed.',
+            'If *small digits*, small digits are displayed for minor ticks.',
+            'If *full value*, full values are displayed for minor ticks.',
+        ].join(' ')
+    },
     uirevision: {
         valType: 'any',
         editType: 'none',

src/plots/cartesian/tick_label_defaults.js

@@ -70,6 +70,10 @@ module.exports = function handleTickLabelDefaults(containerIn, containerOut, coe
                 coerce('separatethousands');
             }
         }
+
+        if(axType === 'log') {
+            coerce('loglabels');
+        }
     }
 };