refactor: rename min/max scale limits

Author: mojoaxel

src/components/modebar/buttons.js

@@ -548,16 +548,16 @@ function handleGeo(gd, ev) {
 
         if(attr === 'zoom') {
             var scale = geoLayout.projection.scale;
-            var minScale = geoLayout.projection.minScale;
-            var maxScale = geoLayout.projection.maxScale;
+            var minscale = geoLayout.projection.minscale;
+            var maxscale = geoLayout.projection.maxscale;
 
             var newScale = (val === 'in') ? 2 * scale : 0.5 * scale;
 
             // make sure the scale is within the min/max bounds
-            if(newScale > maxScale) {
-                newScale = maxScale;
-            } else if(newScale < minScale) {
-                newScale = minScale;
+            if(newScale > maxscale) {
+                newScale = maxscale;
+            } else if(newScale < minscale) {
+                newScale = minscale;
             }
 
             Registry.call('_guiRelayout', gd, id + '.projection.scale', newScale);

src/plots/geo/geo.js

@@ -747,6 +747,13 @@ function getProjection(geoLayout) {
 
 	projection.precision(constants.precision);
 
+	// https://github.com/d3/d3-zoom/blob/master/README.md#zoom_scaleExtent
+	projection.scaleExtent = function () {
+		var minscale = projLayout.minscale * 100;
+		var maxscale = projLayout.maxscale * 100;
+		return [minscale, maxscale];
+	};
+
 	if (geoLayout._isSatellite) {
 		projection.tilt(projLayout.tilt).distance(projLayout.distance);
 	}

src/plots/geo/layout_attributes.js

@@ -177,7 +177,7 @@ var attrs = module.exports = overrideAll({
                 'that fits the map\'s lon and lat ranges. '
             ].join(' ')
         },
-        minScale: {
+        minscale: {
             valType: 'number',
             role: 'info',
             min: 0,
@@ -188,11 +188,11 @@ var attrs = module.exports = overrideAll({
                 'where the map has half the size of base zoom level.'
             ].join(' ')
         },
-        maxScale: {
+        maxscale: {
             valType: 'number',
             role: 'info',
             min: 0,
-            dflt: Infinity,
+            dflt: null,
             description: [
                 'Maximal zoom level of the map view.',
                 'A maxScale of *2* (200%) corresponds to a zoom level',

src/plots/geo/layout_defaults.js

@@ -161,8 +161,8 @@ function handleGeoDefaults(geoLayoutIn, geoLayoutOut, coerce, opts) {
     }
 
     coerce('projection.scale');
-    coerce('projection.minScale');
-    coerce('projection.maxScale');
+    coerce('projection.minscale');
+    coerce('projection.maxscale');
 
     show = coerce('showland', !visible ? false : undefined);
     if(show) coerce('landcolor');
@@ -207,8 +207,8 @@ function handleGeoDefaults(geoLayoutIn, geoLayoutOut, coerce, opts) {
     // clear attributes that will get auto-filled later
     if(fitBounds) {
         delete geoLayoutOut.projection.scale;
-        delete geoLayoutOut.projection.minScale;
-        delete geoLayoutOut.projection.maxScale;
+        delete geoLayoutOut.projection.minscale;
+        delete geoLayoutOut.projection.maxscale;
 
         if(isScoped) {
             delete geoLayoutOut.center.lon;