resolves #2547 - target altered axes only on "axrange" edits

- by passing (now correct) alteredRange hash object to doTicksRelayout
- by addding new doTicks(gd, [axId, axId2, ...]) call signature
- clean up doTicks docstring
- N.B. not implemented for Plotly.react (yet)

Author: etpinard

src/plot_api/plot_api.js

@@ -1689,12 +1689,9 @@ exports.relayout = function relayout(gd, astr, val) {
             // subroutine of its own so that finalDraw always gets
             // executed after drawData
             seq.push(
-                // TODO
-                // can target specific axes,
-                // do not have to redraw all axes here
-                // See:
-                // https://github.com/plotly/plotly.js/issues/2547
-                subroutines.doTicksRelayout,
+                function(gd) {
+                    return subroutines.doTicksRelayout(gd, specs.rangesAltered);
+                },
                 subroutines.drawData,
                 subroutines.finalDraw
             );
@@ -2058,6 +2055,7 @@ function _relayout(gd, aobj) {
 
     return {
         flags: flags,
+        rangesAltered: rangesAltered,
         undoit: undoit,
         redoit: redoit,
         eventData: Lib.extendDeep({}, redoit)
@@ -2171,7 +2169,9 @@ exports.update = function update(gd, traceUpdate, layoutUpdate, _traces) {
         if(relayoutFlags.layoutstyle) seq.push(subroutines.layoutStyles);
         if(relayoutFlags.axrange) {
             seq.push(
-                subroutines.doTicksRelayout,
+                function(gd) {
+                    return subroutines.doTicksRelayout(gd, relayoutSpecs.rangesAltered);
+                },
                 subroutines.drawData,
                 subroutines.finalDraw
             );

src/plot_api/subroutines.js

@@ -448,8 +448,12 @@ exports.doLegend = function(gd) {
     return Plots.previousPromises(gd);
 };
 
-exports.doTicksRelayout = function(gd) {
-    Axes.doTicks(gd, 'redraw');
+exports.doTicksRelayout = function(gd, rangesAltered) {
+    if(rangesAltered) {
+        Axes.doTicks(gd, Object.keys(rangesAltered), true);
+    } else {
+        Axes.doTicks(gd, 'redraw');
+    }
 
     if(gd._fullLayout._hasOnlyLargeSploms) {
         clearGlCanvases(gd);

src/plots/cartesian/axes.js

@@ -1498,28 +1498,50 @@ axes.makeClipPaths = function(gd) {
     });
 };
 
-// doTicks: draw ticks, grids, and tick labels
-// axid: 'x', 'y', 'x2' etc,
-//     blank to do all,
-//     'redraw' to force full redraw, and reset:
-//          ax._r (stored range for use by zoom/pan)
-//          ax._rl (stored linearized range for use by zoom/pan)
-//     or can pass in an axis object directly
-axes.doTicks = function(gd, axid, skipTitle) {
+/** Main axis drawing routine!
+ *
+ * This routine draws axis ticks and much more (... grids, labels, title etc.)
+ * Supports multiple argument signatures.
+ * N.B. this thing is async in general (because of MathJax rendering)
+ *
+ * @param {DOM element} gd : graph div
+ * @param {object or string or array of strings} arg : polymorphic argument
+ * @param {boolean} skipTitle : optional flag to skip axis title draw/update
+ * @return {promise}
+ *
+ * Signature 1: Axes.doTicks(gd, ax)
+ *   where ax is an axis object as in fullLayout
+ *
+ * Signature 2: Axes.doTicks(gd, axId)
+ *   where axId is a axis id string
+ *
+ * Signature 3: Axes.doTicks(gd, 'redraw')
+ *   use this to clear and redraw all axes on graph
+ *
+ * Signature 4: Axes.doTicks(gd, '')
+ *   use this to draw all axes on graph w/o the selectAll().remove()
+ *   of the 'redraw' signature
+ *
+ * Signature 5: Axes.doTicks(gd, [axId, axId2, ...])
+ *   where the items are axis id string,
+ *   use this to update multiple axes in one call
+ *
+ * N.B signatures 3, 4 and 5 reset:
+ * - ax._r (stored range for use by zoom/pan)
+ * - ax._rl (stored linearized range for use by zoom/pan)
+ */
+axes.doTicks = function(gd, arg, skipTitle) {
     var fullLayout = gd._fullLayout;
-    var ax;
     var independent = false;
+    var ax;
 
-    // allow passing an independent axis object instead of id
-    if(typeof axid === 'object') {
-        ax = axid;
-        axid = ax._id;
+    if(Lib.isPlainObject(arg)) {
+        ax = arg;
         independent = true;
-    }
-    else {
-        ax = axes.getFromId(gd, axid);
+    } else if(!arg || arg === 'redraw' || Array.isArray(arg)) {
+        var axList = (!arg || arg === 'redraw') ? axes.listIds(gd) : arg;
 
-        if(axid === 'redraw') {
+        if(arg === 'redraw') {
             fullLayout._paper.selectAll('g.subplot').each(function(subplot) {
                 var plotinfo = fullLayout._plots[subplot];
                 var xa = plotinfo.xaxis;
@@ -1534,22 +1556,24 @@ axes.doTicks = function(gd, axid, skipTitle) {
             });
         }
 
-        if(!axid || axid === 'redraw') {
-            return Lib.syncOrAsync(axes.list(gd, '', true).map(function(ax) {
-                return function() {
-                    if(!ax._id) return;
-                    var axDone = axes.doTicks(gd, ax._id);
-                    ax._r = ax.range.slice();
-                    ax._rl = Lib.simpleMap(ax._r, ax.r2l);
-                    return axDone;
-                };
-            }));
-        }
+        return Lib.syncOrAsync(axList.map(function(a) {
+            return function() {
+                if(!a) return;
+                var axDone = axes.doTicks(gd, a);
+                var ax = axes.getFromId(gd, a);
+                ax._r = ax.range.slice();
+                ax._rl = Lib.simpleMap(ax._r, ax.r2l);
+                return axDone;
+            };
+        }));
+    } else {
+        ax = axes.getFromId(gd, arg);
     }
 
     // set scaling to pixels
     ax.setScale();
 
+    var axid = ax._id;
     var axLetter = axid.charAt(0);
     var counterLetter = axes.counterLetter(axid);
     var vals = ax._vals = axes.calcTicks(ax);