Add support for single point line plots

Author: robertoffmoura

Diff for: plotly/plotlyfig_aux/handlegraphics/updateLineseries.m

@@ -51,7 +51,6 @@ function updateLineseries(obj, plotIndex)
         obj.data{plotIndex}.type = 'scatterpolar';
         updateDefaultPolaraxes(obj, plotIndex)
         obj.data{plotIndex}.subplot = sprintf('polar%d', xSource+1);
-
     elseif ~isPlot3D
         obj.data{plotIndex}.type = 'scatter';
         obj.data{plotIndex}.xaxis = sprintf('x%d', xSource);
@@ -73,11 +72,15 @@ function updateLineseries(obj, plotIndex)
     if isPolar
         obj.data{plotIndex}.r = rData;
         obj.data{plotIndex}.theta = thetaData;
-
     else
         obj.data{plotIndex}.x = xData;
         obj.data{plotIndex}.y = yData;
 
+        if isscalar(xData) % plotly has trouble plotting a single point
+            obj.data{plotIndex}.x = repmat(obj.data{plotIndex}.x,[1,2]);
+            obj.data{plotIndex}.y = repmat(obj.data{plotIndex}.y,[1,2]);
+        end
+
         if isPlot3D
             obj.data{plotIndex}.z = zData;
             obj.PlotOptions.is3d = true;