Add support for dashed marker lines in scatter plots

- Enable `marker.line.dash` attribute in scatter trace definitions with support for array values - Apply dash patterns to marker outlines in both open and closed marker styles - Merge dash data into calcdata for per-point dash styling - Include dash information in legend marker rendering to match trace appearance - Default dash handling falls back to trace-level `marker.line.dash` when per-point values are not specified
plotly · camdecoster · Feb 2, 2026 · Dec 12, 2025 · Dec 12, 2025 · Dec 12, 2025
commit de99bdc2fc44d293e4726c12363c444fbac39f7b
diff --git a/src/components/drawing/index.js b/src/components/drawing/index.js
@@ -965,13 +965,16 @@ drawing.singlePointStyle = function (d, sel, trace, fns, gd, pt) {
         }
     }
 
+    var lineDash = d.mld || (markerLine || {}).dash;
+
     if (d.om) {
         // open markers can't have zero linewidth, default to 1px,
         // and use fill color as stroke color
         sel.call(Color.stroke, fillColor).style({
             'stroke-width': (lineWidth || 1) + 'px',
             fill: 'none'
         });
+        drawing.dashLine(sel, lineDash, lineWidth || 1);
     } else {
         sel.style('stroke-width', (d.isBlank ? 0 : lineWidth) + 'px');
 
@@ -1057,6 +1060,7 @@ drawing.singlePointStyle = function (d, sel, trace, fns, gd, pt) {
 
         if (lineWidth) {
             Color.stroke(sel, lineColor);
+            drawing.dashLine(sel, lineDash, lineWidth);
         }
     }
 };

diff --git a/src/components/legend/style.js b/src/components/legend/style.js
@@ -221,6 +221,7 @@ module.exports = function style(s, gd, legend) {
                 dEdit.mo = boundVal('marker.opacity', Lib.mean, [0.2, 1]);
                 dEdit.mlc = boundVal('marker.line.color', pickFirst);
                 dEdit.mlw = boundVal('marker.line.width', Lib.mean, [0, 5], CST_MARKER_LINE_WIDTH);
+                dEdit.mld = boundVal('marker.line.dash', pickFirst);
                 tEdit.marker = {
                     sizeref: 1,
                     sizemin: 1,

diff --git a/src/traces/scatter/arrays_to_calcdata.js b/src/traces/scatter/arrays_to_calcdata.js
@@ -38,6 +38,7 @@ module.exports = function arraysToCalcdata(cd, trace) {
         if(marker.line) {
             Lib.mergeArray(markerLine.color, cd, 'mlc');
             Lib.mergeArrayCastPositive(markerLine.width, cd, 'mlw');
+            Lib.mergeArray(markerLine.dash, cd, 'mld');
         }
 
         var markerGradient = marker.gradient;

diff --git a/src/traces/scatter/attributes.js b/src/traces/scatter/attributes.js
@@ -555,6 +555,10 @@ module.exports = {
                         anim: true,
                         description: 'Sets the width (in px) of the lines bounding the marker points.'
                     },
+                    dash: extendFlat({}, dash, {
+                        arrayOk: true,
+                        editType: 'style'
-                        editType: 'style'
-                        editType: 'style'
+                    }),
                     editType: 'calc'
                 },
                 colorScaleAttrs('marker.line', { anim: true })

diff --git a/src/traces/scatter/marker_defaults.js b/src/traces/scatter/marker_defaults.js
@@ -64,6 +64,7 @@ module.exports = function markerDefaults(traceIn, traceOut, defaultColor, layout
         }
 
         coerce('marker.line.width', isBubble ? 1 : 0);
+        coerce('marker.line.dash');
     }
 
     if(isBubble) {
-Original file line number
+Diff line change
@@ Expand Up @@
             }
             coerce('marker.line.width', isBubble ? 1 : 0);
+            coerce('marker.line.dash');
         }
         if(isBubble) {
@@ Expand Down @@