Fixed linecharts

Author: OssianEPPlus

src/EPPlus.Export.ImageRenderer/Svg/Chart/SvgChartLegend.cs

@@ -103,16 +103,24 @@ private SvgRenderRectItem GetLegendRectangleAndEntrySize(SvgChart sc, ExcelChart
                     var text = s.GetHeaderText(index);
                     var entry = l.Entries.FirstOrDefault(x => x.Index == index);
                     ExcelTextFont font;
+                    MeasurementFont mf;
                     if(entry==null || entry.Font.IsEmpty)
                     {
                         font = l.Font;
+                        mf = l.Font.GetMeasureFont();
                     }
                     else
                     {
                         font = entry.Font;
+                        mf = entry.Font.GetMeasureFont();
                     }
 
-                    var tm = _ttMeasurer.MeasureText(text, font.GetMeasureFont());
+                    if(_ttMeasurer == null)
+                    {
+                        _ttMeasurer = new OpenTypeFontTextMeasurer(OpenTypeFonts.GetShaperForFont(mf));
+                    }
+
+                    var tm = _ttMeasurer.MeasureText(text, mf);
                     _seriesHeadersMeasure.Add(tm);
 
                     if(tm.Width > widest)