Add clustering options to scattermapbox

draftlogs/5827_add.md

@@ -0,0 +1,2 @@
+ - Add clustering options to `scattermapbox` [[#5827](https://github.com/plotly/plotly.js/pull/5827)],
+   with thanks to @elben10 for the contribution!

src/traces/scattermapbox/attributes.js

@@ -10,6 +10,7 @@ var colorScaleAttrs = require('../../components/colorscale/attributes');
 
 var extendFlat = require('../../lib/extend').extendFlat;
 var overrideAll = require('../../plot_api/edit_types').overrideAll;
+var mapboxLayoutAtributes = require('../../plots/mapbox/layout_attributes');
 
 var lineAttrs = scatterGeoAttrs.line;
 var markerAttrs = scatterGeoAttrs.marker;
@@ -18,6 +19,50 @@ module.exports = overrideAll({
     lon: scatterGeoAttrs.lon,
     lat: scatterGeoAttrs.lat,
 
+    cluster: {
+        enabled: {
+            valType: 'boolean',
+            description: 'Determines whether clustering is enabled or disabled.'
+        },
+        maxzoom: extendFlat({}, mapboxLayoutAtributes.layers.maxzoom, {
+            description: [
+                'Sets the maximum zoom level.',
+                'At zoom levels equal to or greater than this, points will never be clustered.'
+            ].join(' ')
+        }),
+        step: {
+            valType: 'number',
+            arrayOk: true,
+            dflt: -1,
+            min: -1,
+            description: [
+                'Sets how many points it takes to create a cluster or advance to the next cluster step.',
+                'Use this in conjunction with arrays for `size` and / or `color`.',
+                'If an integer, steps start at multiples of this number.',
+                'If an array, each step extends from the given value until one less than the next value.'
+            ].join(' ')
+        },
+        size: {
+            valType: 'number',
+            arrayOk: true,
+            dflt: 20,
+            min: 0,
+            description: [
+                'Sets the size for each cluster step.'
+            ].join(' ')
+        },
+        color: {
+            valType: 'color',
+            arrayOk: true,
+            description: [
+                'Sets the color for each cluster step.'
+            ].join(' ')
+        },
+        opacity: extendFlat({}, markerAttrs.opacity, {
+            dflt: 1
+        })
+    },
+
     // locations
     // locationmode
 

src/traces/scattermapbox/convert.js

@@ -26,11 +26,12 @@ module.exports = function convert(gd, calcTrace) {
     var hasText = subTypes.hasText(trace);
     var hasCircles = (hasMarkers && trace.marker.symbol === 'circle');
     var hasSymbols = (hasMarkers && trace.marker.symbol !== 'circle');
+    var hasCluster = trace.cluster && trace.cluster.enabled;
 
-    var fill = initContainer();
-    var line = initContainer();
-    var circle = initContainer();
-    var symbol = initContainer();
+    var fill = initContainer('fill');
+    var line = initContainer('line');
+    var circle = initContainer('circle');
+    var symbol = initContainer('symbol');
 
     var opts = {
         fill: fill,
@@ -74,6 +75,29 @@ module.exports = function convert(gd, calcTrace) {
         var circleOpts = makeCircleOpts(calcTrace);
         circle.geojson = circleOpts.geojson;
         circle.layout.visibility = 'visible';
+        if(hasCluster) {
+            circle.filter = ['!', ['has', 'point_count']];
+            opts.cluster = {
+                type: 'circle',
+                filter: ['has', 'point_count'],
+                layout: {visibility: 'visible'},
+                paint: {
+                    'circle-color': arrayifyAttribute(trace.cluster.color, trace.cluster.step),
+                    'circle-radius': arrayifyAttribute(trace.cluster.size, trace.cluster.step),
+                    'circle-opacity': arrayifyAttribute(trace.cluster.opacity, trace.cluster.step),
+                },
+            };
+            opts.clusterCount = {
+                type: 'symbol',
+                filter: ['has', 'point_count'],
+                paint: {},
+                layout: {
+                    'text-field': '{point_count_abbreviated}',
+                    'text-font': ['Open Sans Regular', 'Arial Unicode MS Regular'],
+                    'text-size': 12
+                }
+            };
+        }
 
         Lib.extendFlat(circle.paint, {
             'circle-color': circleOpts.mcc,
@@ -82,6 +106,10 @@ module.exports = function convert(gd, calcTrace) {
         });
     }
 
+    if(hasCircles && hasCluster) {
+        circle.filter = ['!', ['has', 'point_count']];
+    }
+
     if(hasSymbols || hasText) {
         symbol.geojson = makeSymbolGeoJSON(calcTrace, gd);
 
@@ -142,10 +170,12 @@ module.exports = function convert(gd, calcTrace) {
     return opts;
 };
 
-function initContainer() {
+function initContainer(type) {
     return {
+        type: type,
         geojson: geoJsonUtils.makeBlank(),
         layout: { visibility: 'none' },
+        filter: null,
         paint: {}
     };
 }
@@ -200,7 +230,8 @@ function makeCircleOpts(calcTrace) {
 
         features.push({
             type: 'Feature',
-            geometry: {type: 'Point', coordinates: lonlat},
+            id: i + 1,
+            geometry: { type: 'Point', coordinates: lonlat },
             properties: props
         });
     }
@@ -323,3 +354,17 @@ function blankFillFunc() { return ''; }
 function isBADNUM(lonlat) {
     return lonlat[0] === BADNUM;
 }
+
+function arrayifyAttribute(values, step) {
+    var newAttribute;
+    if(Lib.isArrayOrTypedArray(values) && Lib.isArrayOrTypedArray(step)) {
+        newAttribute = ['step', ['get', 'point_count'], values[0]];
+
+        for(var idx = 1; idx < values.length; idx++) {
+            newAttribute.push(step[idx - 1], values[idx]);
+        }
+    } else {
+        newAttribute = values;
+    }
+    return newAttribute;
+}

src/traces/scattermapbox/defaults.js

@@ -14,6 +14,10 @@ module.exports = function supplyDefaults(traceIn, traceOut, defaultColor, layout
         return Lib.coerce(traceIn, traceOut, attributes, attr, dflt);
     }
 
+    function coerce2(attr, dflt) {
+        return Lib.coerce2(traceIn, traceOut, attributes, attr, dflt);
+    }
+
     var len = handleLonLatDefaults(traceIn, traceOut, coerce);
     if(!len) {
         traceOut.visible = false;
@@ -46,6 +50,21 @@ module.exports = function supplyDefaults(traceIn, traceOut, defaultColor, layout
         }
     }
 
+    var clusterMaxzoom = coerce2('cluster.maxzoom');
+    var clusterStep = coerce2('cluster.step');
+    var clusterColor = coerce2('cluster.color', (traceOut.marker && traceOut.marker.color) || defaultColor);
+    var clusterSize = coerce2('cluster.size');
+    var clusterOpacity = coerce2('cluster.opacity');
+
+    var clusterEnabledDflt =
+        clusterMaxzoom !== false ||
+        clusterStep !== false ||
+        clusterColor !== false ||
+        clusterSize !== false ||
+        clusterOpacity !== false;
+
+    coerce('cluster.enabled', clusterEnabledDflt);
+
     if(subTypes.hasText(traceOut)) {
         handleTextDefaults(traceIn, traceOut, layout, coerce, {noSelect: true});
     }

src/traces/scattermapbox/hover.js

@@ -5,13 +5,22 @@ var Lib = require('../../lib');
 var getTraceColor = require('../scatter/get_trace_color');
 var fillText = Lib.fillText;
 var BADNUM = require('../../constants/numerical').BADNUM;
+var LAYER_PREFIX = require('../../plots/mapbox/constants').traceLayerPrefix;
 
 function hoverPoints(pointData, xval, yval) {
     var cd = pointData.cd;
     var trace = cd[0].trace;
     var xa = pointData.xa;
     var ya = pointData.ya;
     var subplot = pointData.subplot;
+    var clusteredPointsIds = [];
+    var layer = LAYER_PREFIX + trace.uid + '-circle';
+    var hasCluster = trace.cluster && trace.cluster.enabled;
+
+    if(hasCluster) {
+        var elems = subplot.map.queryRenderedFeatures(null, {layers: [layer]});
+        clusteredPointsIds = elems.map(function(elem) {return elem.id;});
+    }
 
     // compute winding number about [-180, 180] globe
     var winding = (xval >= 0) ?
@@ -25,6 +34,7 @@ function hoverPoints(pointData, xval, yval) {
     function distFn(d) {
         var lonlat = d.lonlat;
         if(lonlat[0] === BADNUM) return Infinity;
+        if(hasCluster && clusteredPointsIds.indexOf(d.i + 1) === -1) return Infinity;
 
         var lon = Lib.modHalf(lonlat[0], 360);
         var lat = lonlat[1];