Constrain axes by domain

src/constants/alignment.js

@@ -0,0 +1,32 @@
+/**
+* Copyright 2012-2017, Plotly, Inc.
+* All rights reserved.
+*
+* This source code is licensed under the MIT license found in the
+* LICENSE file in the root directory of this source tree.
+*/
+
+'use strict';
+
+// fraction of some size to get to a named position
+module.exports = {
+    // from bottom left: this is the origin of our paper-reference
+    // positioning system
+    FROM_BL: {
+        left: 0,
+        center: 0.5,
+        right: 1,
+        bottom: 0,
+        middle: 0.5,
+        top: 1
+    },
+    // from top left: this is the screen pixel positioning origin
+    FROM_TL: {
+        left: 0,
+        center: 0.5,
+        right: 1,
+        bottom: 1,
+        middle: 0.5,
+        top: 0
+    }
+};

src/plot_api/plot_api.js

@@ -190,8 +190,7 @@ Plotly.plot = function(gd, data, layout, config) {
 
         return Lib.syncOrAsync([
             subroutines.layoutStyles,
-            drawAxes,
-            initInteractions
+            drawAxes
         ], gd);
     }
 
@@ -220,19 +219,19 @@ Plotly.plot = function(gd, data, layout, config) {
 
     // in case the margins changed, draw margin pushers again
     function marginPushersAgain() {
-        var seq = JSON.stringify(fullLayout._size) === oldmargins ?
-            [] :
-            [marginPushers, subroutines.layoutStyles];
+        if(JSON.stringify(fullLayout._size) === oldmargins) return;
 
-        // re-initialize cartesian interaction,
-        // which are sometimes cleared during marginPushers
-        seq = seq.concat(initInteractions);
-
-        return Lib.syncOrAsync(seq, gd);
+        return Lib.syncOrAsync([
+            marginPushers,
+            subroutines.layoutStyles
+        ], gd);
     }
 
     function positionAndAutorange() {
-        if(!recalc) return;
+        if(!recalc) {
+            enforceAxisConstraints(gd);
+            return;
+        }
 
         var subplots = Plots.getSubplotIds(fullLayout, 'cartesian'),
             modules = fullLayout._modules;
@@ -270,7 +269,26 @@ Plotly.plot = function(gd, data, layout, config) {
 
         var axList = Plotly.Axes.list(gd, '', true);
         for(var i = 0; i < axList.length; i++) {
-            Plotly.Axes.doAutoRange(axList[i]);
+            // before autoranging, check if this axis was previously constrained
+            // by domain but no longer is
+            var ax = axList[i];
+            if(ax._inputDomain) {
+                var isConstrained = false;
+                var axId = ax._id;
+                var constraintGroups = gd._fullLayout._axisConstraintGroups;
+                for(var j = 0; j < constraintGroups.length; j++) {
+                    if(constraintGroups[j][axId]) {
+                        isConstrained = true;
+                        break;
+                    }
+                }
+                if(!isConstrained || ax.constrain !== 'domain') {
+                    ax._input.domain = ax.domain = ax._inputDomain;
+                    delete ax._inputDomain;
+                }
+            }
+
+            Plotly.Axes.doAutoRange(ax);
         }
 
         enforceAxisConstraints(gd);
@@ -365,11 +383,13 @@ Plotly.plot = function(gd, data, layout, config) {
         drawFramework,
         marginPushers,
         marginPushersAgain,
+        initInteractions,
         positionAndAutorange,
         subroutines.layoutStyles,
         drawAxes,
         drawData,
         finalDraw,
+        initInteractions,
         Plots.rehover
     ];
 
@@ -1917,10 +1937,12 @@ function _relayout(gd, aobj) {
     // we're editing the (auto)range of, so we can tell the others constrained
     // to scale with them that it's OK for them to shrink
     var rangesAltered = {};
+    var axId;
 
     function recordAlteredAxis(pleafPlus) {
         var axId = axisIds.name2id(pleafPlus.split('.')[0]);
         rangesAltered[axId] = 1;
+        return axId;
     }
 
     // alter gd.layout
@@ -1963,11 +1985,26 @@ function _relayout(gd, aobj) {
         else if(pleafPlus.match(/^[xyz]axis[0-9]*\.range(\[[0|1]\])?$/)) {
             doextra(ptrunk + '.autorange', false);
             recordAlteredAxis(pleafPlus);
+            Lib.nestedProperty(fullLayout, ptrunk + '._inputRange').set(null);
         }
         else if(pleafPlus.match(/^[xyz]axis[0-9]*\.autorange$/)) {
             doextra([ptrunk + '.range[0]', ptrunk + '.range[1]'],
                 undefined);
             recordAlteredAxis(pleafPlus);
+            Lib.nestedProperty(fullLayout, ptrunk + '._inputRange').set(null);
+            var axFull = Lib.nestedProperty(fullLayout, ptrunk).get();
+            if(axFull._inputDomain) {
+                // if we're autoranging and this axis has a constrained domain,
+                // reset it so we don't get locked into a shrunken size
+                axFull._input.domain = axFull._inputDomain.slice();
+            }
+        }
+        else if(pleafPlus.match(/^[xyz]axis[0-9]*\.domain(\[[0|1]\])?$/)) {
+            axId = recordAlteredAxis(pleafPlus);
+            Lib.nestedProperty(fullLayout, ptrunk + '._inputDomain').set(null);
+        }
+        else if(pleafPlus.match(/^[xyz]axis[0-9]*\.constrain.*$/)) {
+            flags.docalc = true;
         }
         else if(pleafPlus.match(/^aspectratio\.[xyz]$/)) {
             doextra(proot + '.aspectmode', 'manual');
@@ -2047,6 +2084,7 @@ function _relayout(gd, aobj) {
                 // will not make sense, so autorange it.
                 doextra(ptrunk + '.autorange', true);
             }
+            Lib.nestedProperty(fullLayout, ptrunk + '._inputRange').set(null);
         }
         else if(pleaf.match(cartesianConstants.AX_NAME_PATTERN)) {
             var fullProp = Lib.nestedProperty(fullLayout, ai).get(),
@@ -2193,7 +2231,7 @@ function _relayout(gd, aobj) {
 
     // figure out if we need to recalculate axis constraints
     var constraints = fullLayout._axisConstraintGroups;
-    for(var axId in rangesAltered) {
+    for(axId in rangesAltered) {
         for(i = 0; i < constraints.length; i++) {
             var group = constraints[i];
             if(group[axId]) {

src/plots/cartesian/axes.js

@@ -455,6 +455,13 @@ axes.expand = function(ax, data, options) {
         i, j, v, di, dmin, dmax,
         ppadiplus, ppadiminus, includeThis, vmin, vmax;
 
+    // domain-constrained axes: base extrappad on the unconstrained
+    // domain so it's consistent as the domain changes
+    if(extrappad && ax._inputDomain) {
+        extrappad *= (ax._inputDomain[1] - ax._inputDomain[0]) /
+            (ax.domain[1] - ax.domain[0]);
+    }
+
     function getPad(item) {
         if(Array.isArray(item)) {
             return function(i) { return Math.max(Number(item[i]||0), 0); };

src/plots/cartesian/constraint_defaults.js

@@ -15,10 +15,25 @@ var id2name = require('./axis_ids').id2name;
 
 module.exports = function handleConstraintDefaults(containerIn, containerOut, coerce, allAxisIds, layoutOut) {
     var constraintGroups = layoutOut._axisConstraintGroups;
+    var thisID = containerOut._id;
+    var letter = thisID.charAt(0);
 
-    if(containerOut.fixedrange || !containerIn.scaleanchor) return;
+    if(containerOut.fixedrange) return;
 
-    var constraintOpts = getConstraintOpts(constraintGroups, containerOut._id, allAxisIds, layoutOut);
+    // coerce the constraint mechanics even if this axis has no scaleanchor
+    // because it may be the anchor of another axis.
+    coerce('constrain');
+    Lib.coerce(containerIn, containerOut, {
+        constraintoward: {
+            valType: 'enumerated',
+            values: letter === 'x' ? ['left', 'center', 'right'] : ['bottom', 'middle', 'top'],
+            dflt: letter === 'x' ? 'center' : 'middle'
+        }
+    }, 'constraintoward');
+
+    if(!containerIn.scaleanchor) return;
+
+    var constraintOpts = getConstraintOpts(constraintGroups, thisID, allAxisIds, layoutOut);
 
     var scaleanchor = Lib.coerce(containerIn, containerOut, {
         scaleanchor: {
@@ -37,7 +52,7 @@ module.exports = function handleConstraintDefaults(containerIn, containerOut, co
         if(!scaleratio) scaleratio = containerOut.scaleratio = 1;
 
         updateConstraintGroups(constraintGroups, constraintOpts.thisGroup,
-            containerOut._id, scaleanchor, scaleratio);
+            thisID, scaleanchor, scaleratio);
     }
     else if(allAxisIds.indexOf(containerIn.scaleanchor) !== -1) {
         Lib.warn('ignored ' + containerOut._name + '.scaleanchor: "' +

src/plots/cartesian/constraints.js

@@ -14,12 +14,14 @@ var scaleZoom = require('./scale_zoom');
 
 var ALMOST_EQUAL = require('../../constants/numerical').ALMOST_EQUAL;
 
+var FROM_BL = require('../../constants/alignment').FROM_BL;
+
 
 module.exports = function enforceAxisConstraints(gd) {
     var fullLayout = gd._fullLayout;
     var constraintGroups = fullLayout._axisConstraintGroups;
 
-    var i, j, axisID, ax, normScale;
+    var i, j, axisID, ax, normScale, mode, factor;
 
     for(i = 0; i < constraintGroups.length; i++) {
         var group = constraintGroups[i];
@@ -41,6 +43,9 @@ module.exports = function enforceAxisConstraints(gd) {
             axisID = axisIDs[j];
             axes[axisID] = ax = fullLayout[id2name(axisID)];
 
+            if(!ax._inputDomain) ax._inputDomain = ax.domain.slice();
+            if(!ax._inputRange) ax._inputRange = ax.range.slice();
+
             // set axis scale here so we can use _m rather than
             // having to calculate it from length and range
             ax.setScale();
@@ -65,10 +70,115 @@ module.exports = function enforceAxisConstraints(gd) {
         for(j = 0; j < axisIDs.length; j++) {
             axisID = axisIDs[j];
             normScale = normScales[axisID];
+            ax = axes[axisID];
+            mode = ax.constrain;
+
+            // even if the scale didn't change, if we're shrinking domain
+            // we need to recalculate in case `constraintoward` changed
+            if(normScale !== matchScale || mode === 'domain') {
+                factor = normScale / matchScale;
+
+                if(mode === 'range') {
+                    scaleZoom(ax, factor);
+                }
+                else {
+                    // mode === 'domain'
+
+                    var inputDomain = ax._inputDomain;
+                    var domainShrunk = (ax.domain[1] - ax.domain[0]) /
+                        (inputDomain[1] - inputDomain[0]);
+                    var rangeShrunk = (ax.r2l(ax.range[1]) - ax.r2l(ax.range[0])) /
+                        (ax.r2l(ax._inputRange[1]) - ax.r2l(ax._inputRange[0]));
+
+                    factor /= domainShrunk;
+
+                    if(factor * rangeShrunk < 1) {
+                        // we've asked to magnify the axis more than we can just by
+                        // enlarging the domain - so we need to constrict range
+                        ax.domain = ax._input.domain = inputDomain.slice();
+                        scaleZoom(ax, factor);
+                        continue;
+                    }
+
+                    if(rangeShrunk < 1) {
+                        // the range has previously been constricted by ^^, but we've
+                        // switched to the domain-constricted regime, so reset range
+                        ax.range = ax._input.range = ax._inputRange.slice();
+                        factor *= rangeShrunk;
+                    }
 
-            if(normScale !== matchScale) {
-                scaleZoom(axes[axisID], normScale / matchScale);
+                    // TODO
+                    if(ax.autorange) {
+                        /*
+                         * range & factor may need to change because range was
+                         * calculated for the larger scaling, so some pixel
+                         * paddings may get cut off when we reduce the domain.
+                         *
+                         * This is easier than the regular autorange calculation
+                         * because we already know the scaling `m`, but we still
+                         * need to cut out impossible constraints (like
+                         * annotations with super-long arrows). That's what
+                         * outerMin/Max are for - if the expansion was going to
+                         * go beyond the original domain, it must be impossible
+                         */
+                        var rangeMin = Math.min(ax.range[0], ax.range[1]);
+                        var rangeMax = Math.max(ax.range[0], ax.range[1]);
+                        var rangeCenter = (rangeMin + rangeMax) / 2;
+                        var halfRange = rangeMax - rangeCenter;
+                        var outerMin = rangeCenter - halfRange * factor;
+                        var outerMax = rangeCenter + halfRange * factor;
+
+                        updateDomain(ax, factor);
+                        ax.setScale();
+                        var m = Math.abs(ax._m);
+                        var newVal;
+                        var k;
+
+                        for(k = 0; k < ax._min.length; k++) {
+                            newVal = ax._min[i].val - ax._min[i].pad / m;
+                            if(newVal > outerMin && newVal < rangeMin) {
+                                rangeMin = newVal;
+                            }
+                        }
+
+                        for(k = 0; k < ax._max.length; k++) {
+                            newVal = ax._max[i].val + ax._max[i].pad / m;
+                            if(newVal < outerMax && newVal > rangeMax) {
+                                rangeMax = newVal;
+                            }
+                        }
+
+                        ax.range = ax._input.range = (ax.range[0] < ax.range[1]) ?
+                            [rangeMin, rangeMax] : [rangeMax, rangeMin];
+
+                        /*
+                         * In principle this new range can be shifted vs. what
+                         * you saw at the end of a zoom operation, like if you
+                         * have a big bubble on one side and a small bubble on
+                         * the other.
+                         * To fix this we'd have to be doing this calculation
+                         * continuously during the zoom, but it's enough of an
+                         * edge case and a subtle enough effect that I'm going
+                         * to ignore it for now.
+                         */
+                        var domainExpand = (rangeMax - rangeMin) / (2 * halfRange);
+                        factor /= domainExpand;
+                    }
+
+                    updateDomain(ax, factor);
+                }
             }
         }
     }
 };
+
+function updateDomain(ax, factor) {
+    var inputDomain = ax._inputDomain;
+    var centerFraction = FROM_BL[ax.constraintoward];
+    var center = inputDomain[0] + (inputDomain[1] - inputDomain[0]) * centerFraction;
+
+    ax.domain = ax._input.domain = [
+        center + (inputDomain[0] - center) / factor,
+        center + (inputDomain[1] - center) / factor
+    ];
+}