set radialaxis.rangemode dflt to 'tozero' + add support for -ve r ranges

Author: etpinard

src/plots/polar/layout_attributes.js

@@ -68,9 +68,21 @@ var radialAxisAttrs = {
     // -> mpl allow radial ranges to start off 0
     // -> same for matlab: https://www.mathworks.com/help/matlab/ref/rlim.html
     autorange: axesAttrs.autorange,
-    // might make 'nonnegative' the default,
-    // or add a special polar algo.
-    rangemode: axesAttrs.rangemode,
+    rangemode: {
+        valType: 'enumerated',
+        values: ['tozero', 'nonnegative', 'normal'],
+        dflt: 'tozero',
+        role: 'style',
+        editType: 'calc',
+        description: [
+            'If *tozero*`, the range extends to 0,',
+            'regardless of the input data',
+            'If *nonnegative*, the range is non-negative,',
+            'regardless of the input data.',
+            'If *normal*, the range is computed in relation to the extrema',
+            'of the input data (same behavior as for cartesian axes).'
+        ].join(' ')
+    },
     range: axesAttrs.range,
 
     categoryorder: axesAttrs.categoryorder,

src/plots/polar/layout_defaults.js

@@ -83,14 +83,19 @@ function handleDefaults(contIn, contOut, coerce, opts) {
         // as both radial and angular axes don't have a set domain.
         // Furthermore, angular axes don't have a set range.
         //
-        // Mocked domains and ranges are set by the polar subplot instances.
-        // By setting, _m to 1 here, we make Axes.expand think that range[1] > range[0].
+        // Mocked domains and ranges are set by the polar subplot instances,
+        // but Axes.expand uses the sign of _m to determine which padding value
+        // to use.
+        //
+        // By setting, _m to 1 here, we make Axes.expand think that range[1] > range[0],
+        // and vice-versa for `autorange: 'reversed'` below.
         axOut._m = 1;
 
         switch(axName) {
             case 'radialaxis':
                 var autoRange = coerceAxis('autorange', !axOut.isValidRange(axIn.range));
                 if(autoRange) coerceAxis('rangemode');
+                if(autoRange === 'reversed') axOut._m = -1;
 
                 coerceAxis('range');
                 axOut.cleanRange('range', {dfltRange: [0, 1]});

src/plots/polar/polar.js

@@ -791,6 +791,7 @@ proto.updateRadialDrag = function(fullLayout, polarLayout) {
     var radialLayout = polarLayout.radialaxis;
     var angle0 = deg2rad(radialLayout.position);
     var range0 = radialAxis.range.slice();
+    var drange = range0[1] - range0[0];
 
     if(!radialLayout.visible) return;
 
@@ -825,9 +826,9 @@ proto.updateRadialDrag = function(fullLayout, polarLayout) {
     }
 
     function doneFn() {
-        if(angle1) {
+        if(angle1 !== null) {
             Plotly.relayout(gd, _this.id + '.radialaxis.position', angle1);
-        } else if(rng1) {
+        } else if(rng1 !== null) {
             Plotly.relayout(gd, _this.id + '.radialaxis.range[1]', rng1);
         }
     }
@@ -843,15 +844,20 @@ proto.updateRadialDrag = function(fullLayout, polarLayout) {
         var transform = strTranslate(cx, cy) + strRotate(-angle1);
         layers['radial-axis'].attr('transform', transform);
         layers['radial-line'].select('line').attr('transform', transform);
+
+        var fullLayoutNow = _this.gd._fullLayout;
+        var polarLayoutNow = fullLayoutNow[_this.id];
+        _this.updateRadialAxisTitle(fullLayoutNow, polarLayoutNow, angle1);
     }
 
     function rerangeMove(dx, dy) {
         // project (dx, dy) unto unit radial axis vector
         var dr = Lib.dot([dx, -dy], [Math.cos(angle0), Math.sin(angle0)]);
-        rng1 = range0[1] * (1 - dr / radius);
-        radialAxis.range[1] = rng1;
+        var rprime = range0[1] - drange * dr / radius * 0.75;
 
-        // TODO should we restrict updates to same sign as range0 ???
+        // make sure new range[1] does not change the range[0] -> range[1] sign
+        if((drange > 0) !== (rprime > range0[0])) return;
+        rng1 = radialAxis.range[1] = rprime;
 
         Axes.doTicks(gd, _this.radialAxis, true);
         layers['radial-grid']
@@ -911,11 +917,19 @@ proto.isPtWithinSector = function(d) {
     var deg = wrap360(rad2deg(d.rad));
     var nextTurnDeg = deg + 360;
 
+    var r0, r1;
+    if(radialRange[1] >= radialRange[0]) {
+        r0 = radialRange[0];
+        r1 = radialRange[1];
+    } else {
+        r0 = radialRange[1];
+        r1 = radialRange[0];
+    }
+
     // TODO add calendar support
 
     return (
-        r >= radialRange[0] &&
-        r <= radialRange[1] &&
+        (r >= r0 && r <= r1) &&
         (isFullCircle(sector) ||
             (deg >= s0 && deg <= s1) ||
             (nextTurnDeg >= s0 && nextTurnDeg <= s1)

src/traces/scatterpolar/calc.js

@@ -48,7 +48,7 @@ module.exports = function calc(gd, trace) {
     }
 
     var ppad = calcMarkerSize(trace, len);
-    Axes.expand(radialAxis, rArray, {tozero: true, ppad: ppad});
+    Axes.expand(radialAxis, rArray, {ppad: ppad});
 
     if(angularAxis.type !== 'linear') {
         angularAxis.autorange = true;

src/traces/scatterpolar/plot.js

@@ -23,6 +23,13 @@ module.exports = function plot(subplot, moduleCalcData) {
 
     var radialAxis = subplot.radialAxis;
     var radialRange = radialAxis.range;
+    var rFilter;
+
+    if(radialRange[0] > radialRange[1]) {
+        rFilter = function(v) { return v <= 0; };
+    } else {
+        rFilter = function(v) { return v >= 0; };
+    }
 
     // map (r, theta) first to a 'geometric' r and then to (x,y)
     // on-par with what scatterPlot expects.
@@ -36,7 +43,7 @@ module.exports = function plot(subplot, moduleCalcData) {
                 // convert to 'r' data to fit with mocked polar x/y axis
                 // which are always `type: 'linear'`
                 var rr = radialAxis.c2r(r) - radialRange[0];
-                if(rr >= 0) {
+                if(rFilter(rr)) {
                     var rad = cdi.rad;
                     cdi.x = rr * Math.cos(rad);
                     cdi.y = rr * Math.sin(rad);