feat: Add symlog scale, scattermap zoom fix, and line dash support

src/plots/cartesian/layout_attributes.js

@@ -235,7 +235,7 @@ module.exports = {
         // '-' means we haven't yet run autotype or couldn't find any data
         // it gets turned into linear in gd._fullLayout but not copied back
         // to gd.data like the others are.
-        values: ['-', 'linear', 'log', 'date', 'category', 'multicategory'],
+        values: ['-', 'linear', 'log', 'symlog', 'date', 'category', 'multicategory'],
         dflt: '-',
         editType: 'calc',
         // we forget when an axis has been autotyped, just writing the auto
@@ -247,7 +247,9 @@ module.exports = {
             'Sets the axis type.',
             'By default, plotly attempts to determined the axis type',
             'by looking into the data of the traces that referenced',
-            'the axis in question.'
+            'the axis in question.',
+            'With *symlog*, the axis is log-scaled with a linear range',
+            'around zero.'
         ].join(' ')
     },
     autotypenumbers: {

src/plots/cartesian/set_convert.js

@@ -78,6 +78,16 @@ module.exports = function setConvert(ax, fullLayout) {
         } else return BADNUM;
     }
 
+    function toSymlog(v) {
+        // Using asinh as a smooth approximation to symlog
+        // TODO: Make the linear threshold configurable? Currently implicit 1.
+        return Math.asinh(v) / Math.LN10;
+    }
+
+    function fromSymlog(v) {
+        return Math.sinh(v * Math.LN10);
+    }
+
     /*
      * wrapped dateTime2ms that:
      * - accepts ms numbers for backward compatibility
@@ -241,14 +251,22 @@ module.exports = function setConvert(ax, fullLayout) {
     }
 
     // conversions among c/l/p are fairly simple - do them together for all axis types
-    ax.c2l = (ax.type === 'log') ? toLog : ensureNumber;
-    ax.l2c = (ax.type === 'log') ? fromLog : ensureNumber;
-
-    ax.l2p = l2p;
-    ax.p2l = p2l;
-
-    ax.c2p = (ax.type === 'log') ? function(v, clip) { return l2p(toLog(v, clip)); } : l2p;
-    ax.p2c = (ax.type === 'log') ? function(px) { return fromLog(p2l(px)); } : p2l;
+    if(ax.type === 'log') {
+        ax.c2l = toLog;
+        ax.l2c = fromLog;
+        ax.c2p = function(v, clip) { return l2p(toLog(v, clip)); };
+        ax.p2c = function(px) { return fromLog(p2l(px)); };
+    } else if(ax.type === 'symlog') {
+        ax.c2l = toSymlog;
+        ax.l2c = fromSymlog;
+        ax.c2p = function(v) { return l2p(toSymlog(v)); };
+        ax.p2c = function(px) { return fromSymlog(p2l(px)); };
+    } else {
+        ax.c2l = ensureNumber;
+        ax.l2c = ensureNumber;
+        ax.c2p = l2p;
+        ax.p2c = p2l;
+    }
 
     /*
      * now type-specific conversions for **ALL** other combinations
@@ -281,6 +299,25 @@ module.exports = function setConvert(ax, fullLayout) {
         ax.r2p = function(v) { return ax.l2p(cleanNumber(v)); };
         ax.p2r = p2l;
 
+        ax.cleanPos = ensureNumber;
+    } else if(ax.type === 'symlog') {
+        // Symlog implementation using arcsinh
+        // d and c are data vals, r and l are transformed (symlogged)
+        ax.d2r = ax.d2l = function(v) { return toSymlog(cleanNumber(v)); };
+        ax.r2d = ax.r2c = function(v) { return fromSymlog(cleanNumber(v)); };
+
+        ax.d2c = ax.r2l = cleanNumber;
+        ax.c2d = ax.l2r = ensureNumber;
+
+        ax.c2r = toSymlog;
+        ax.l2d = fromSymlog;
+
+        ax.d2p = function(v) { return ax.l2p(ax.d2r(v)); };
+        ax.p2d = function(px) { return fromSymlog(p2l(px)); };
+
+        ax.r2p = function(v) { return ax.l2p(cleanNumber(v)); };
+        ax.p2r = p2l;
+
         ax.cleanPos = ensureNumber;
     } else if(ax.type === 'date') {
         // r and d are date strings, l and c are ms

src/plots/map/layout_defaults.js

@@ -12,11 +12,12 @@ module.exports = function supplyLayoutDefaults(layoutIn, layoutOut, fullData) {
         type: 'map',
         attributes: layoutAttributes,
         handleDefaults: handleDefaults,
-        partition: 'y'
+        partition: 'y',
+        fullData: fullData
     });
 };
 
-function handleDefaults(containerIn, containerOut, coerce) {
+function handleDefaults(containerIn, containerOut, coerce, opts) {
     coerce('style');
     coerce('center.lon');
     coerce('center.lat');
@@ -28,13 +29,128 @@ function handleDefaults(containerIn, containerOut, coerce) {
     var east = coerce('bounds.east');
     var south = coerce('bounds.south');
     var north = coerce('bounds.north');
+
+    // Auto-calculate bounds from data if not provided
+    if(west === undefined && east === undefined && south === undefined && north === undefined) {
+        var traceBounds = {
+            west: Infinity,
+            east: -Infinity,
+            south: Infinity,
+            north: -Infinity
+        };
+        var hasTraceBounds = false;
+
+        for(var i = 0; i < fullData.length; i++) {
+            var trace = fullData[i];
+            // Check if trace belongs to this map subplot
+            if(trace.visible !== true || trace.subplot !== opts.id) continue;
+
+            // Handle scattermap traces
+            if(trace.type === 'scattermap') {
+                var lon = trace.lon || [];
+                var lat = trace.lat || [];
+                var len = Math.min(lon.length, lat.length);
+
+                for(var j = 0; j < len; j++) {
+                    var l = lon[j];
+                    var t = lat[j];
+                    if(l !== undefined && t !== undefined) {
+                        traceBounds.west = Math.min(traceBounds.west, l);
+                        traceBounds.east = Math.max(traceBounds.east, l);
+                        traceBounds.south = Math.min(traceBounds.south, t);
+                        traceBounds.north = Math.max(traceBounds.north, t);
+                        hasTraceBounds = true;
+                    }
+                }
+            }
+            // Add other map trace types here if needed (choroplethmap, etc)
+        }
+
+    if(hasTraceBounds) {
+        var domain = containerOut.domain;
+        var width = layoutOut.width * (domain.x[1] - domain.x[0]);
+        var height = layoutOut.height * (domain.y[1] - domain.y[0]);
+
+        // Default zoom calculation
+        if(containerOut.zoom === undefined) {
+            var padding = 0.1; // 10% padding
+            var dLon = Math.abs(traceBounds.east - traceBounds.west);
+            if(dLon === 0) dLon = 0.01; // Avoid division by zero
+            if(dLon > 360) dLon = 360;
+
+            // Simple Mercator projection for lat
+            function mercatorY(lat) {
+                var rad = lat * Math.PI / 180;
+                return Math.log(Math.tan(Math.PI / 4 + rad / 2));
+            }
+
+            var yNorth = mercatorY(traceBounds.north);
+            var ySouth = mercatorY(traceBounds.south);
+            var dLat = Math.abs(yNorth - ySouth);
+            if(dLat === 0) dLat = 0.01;
+
+            // 360 degrees = 2*PI radians. Mapbox world width is 512 pixels at zoom 0?
+            // Wait, Mapbox tile size is 512px by default in GL JS.
+            // 360 degrees fits in 512px at z=0?
+            // Let's use 360 degrees fits in 256 * 2^z (standard web mercator)
+            // Mapbox GL usually matches this.
+            // But let's be conservative.
+
+            // Zoom for longitude fit:
+            // pixelWidth = (dLon / 360) * 512 * 2^z
+            // 2^z = (pixelWidth * 360) / (dLon * 512)
+            // z = log2(...)
+            var zLon = Math.log2((width * 360) / (dLon * 512));
+
+            // Zoom for latitude fit:
+            // pixelHeight = (dLat / (2 * Math.PI)) * 512 * 2^z
+            // 2^z = (pixelHeight * 2 * Math.PI) / (dLat * 512)
+            var zLat = Math.log2((height * 2 * Math.PI) / (dLat * 512));
+
+            var zoom = Math.min(zLon, zLat);
+            zoom = Math.max(0, Math.min(22, zoom)); // Clamp to valid zoom range
+            zoom -= padding; // Apply padding
+
+            containerOut.zoom = zoom;
+        }
+
+        // Default center calculation
+        if(containerOut.center.lon === undefined) {
+            containerOut.center.lon = (traceBounds.west + traceBounds.east) / 2;
+        }
+        if(containerOut.center.lat === undefined) {
+            // Center latitude in Mercator projection, then unproject
+            function mercatorY(lat) {
+                var rad = lat * Math.PI / 180;
+                return Math.log(Math.tan(Math.PI / 4 + rad / 2));
+            }
+            function unMercatorY(y) {
+                return (2 * Math.atan(Math.exp(y)) - Math.PI / 2) * 180 / Math.PI;
+            }
+
+            var yNorth = mercatorY(traceBounds.north);
+            var ySouth = mercatorY(traceBounds.south);
+            var yCenter = (yNorth + ySouth) / 2;
+            containerOut.center.lat = unMercatorY(yCenter);
+        }
+
+        // Do NOT set containerOut.bounds here as that restricts panning!
+    }
+    } // End of auto-calculate bounds block
+
     if(
         west === undefined ||
         east === undefined ||
         south === undefined ||
         north === undefined
     ) {
         delete containerOut.bounds;
+
+        if(fitBounds) {
+            delete containerOut.center.lon;
+            delete containerOut.center.lat;
+            delete containerOut.zoom;
+        }
     }
 
     handleArrayContainerDefaults(containerIn, containerOut, {

src/traces/scattermap/attributes.js

@@ -99,10 +99,10 @@ module.exports = overrideAll(
 
         line: {
             color: lineAttrs.color,
-            width: lineAttrs.width
-
-            // TODO
-            // dash: dash
+            width: lineAttrs.width,
+            dash: extendFlat({}, scatterAttrs.line.dash, {
+                editType: 'plot'
+            })
         },
 
         connectgaps: scatterAttrs.connectgaps,

src/traces/scattermap/convert.js

@@ -69,7 +69,9 @@ module.exports = function convert(gd, calcTrace) {
             'line-opacity': trace.opacity
         });
 
-        // TODO convert line.dash into line-dasharray
+        if (trace.line.dash) {
+            line.paint['line-dasharray'] = convertDash(trace.line.dash, trace.line.width);
+        }
     }
 
     if (hasCircles) {
@@ -197,6 +199,24 @@ function makeCircleOpts(calcTrace) {
         return s / 2;
     }
 
+    function convertDash(dash, width) {
+        var dashList;
+        if (dash === 'solid') dashList = [];
+        else if (dash === 'dot') dashList = [1, 2];
+        else if (dash === 'dash') dashList = [4, 2];
+        else if (dash === 'longdash') dashList = [8, 2];
+        else if (dash === 'dashdot') dashList = [4, 2, 1, 2];
+        else if (dash === 'longdashdot') dashList = [8, 2, 1, 2];
+        else if (typeof dash === 'string') dashList = dash.split(/[\s,]+/).map(Number);
+        else dashList = dash;
+
+        if (dashList.length) {
+            return dashList.map(function (v) {
+                return (v * width) / 2;
+            });
+        }
+    }
+
     var colorFn;
     if (arrayColor) {
         if (Colorscale.hasColorscale(trace, 'marker')) {

src/traces/scattermapbox/attributes.js

@@ -99,10 +99,10 @@ module.exports = overrideAll(
 
         line: {
             color: lineAttrs.color,
-            width: lineAttrs.width
-
-            // TODO
-            // dash: dash
+            width: lineAttrs.width,
+            dash: extendFlat({}, scatterAttrs.line.dash, {
+                editType: 'plot'
+            })
         },
 
         connectgaps: scatterAttrs.connectgaps,

src/traces/scattermapbox/convert.js

@@ -69,7 +69,9 @@ module.exports = function convert(gd, calcTrace) {
             'line-opacity': trace.opacity
         });
 
-        // TODO convert line.dash into line-dasharray
+        if (trace.line.dash) {
+            line.paint['line-dasharray'] = convertDash(trace.line.dash, trace.line.width);
+        }
     }
 
     if (hasCircles) {
@@ -197,6 +199,24 @@ function makeCircleOpts(calcTrace) {
         return s / 2;
     }
 
+    function convertDash(dash, width) {
+        var dashList;
+        if (dash === 'solid') dashList = [];
+        else if (dash === 'dot') dashList = [1, 2];
+        else if (dash === 'dash') dashList = [4, 2];
+        else if (dash === 'longdash') dashList = [8, 2];
+        else if (dash === 'dashdot') dashList = [4, 2, 1, 2];
+        else if (dash === 'longdashdot') dashList = [8, 2, 1, 2];
+        else if (typeof dash === 'string') dashList = dash.split(/[\s,]+/).map(Number);
+        else dashList = dash;
+
+        if (dashList.length) {
+            return dashList.map(function (v) {
+                return (v * width) / 2;
+            });
+        }
+    }
+
     var colorFn;
     if (arrayColor) {
         if (Colorscale.hasColorscale(trace, 'marker')) {