Hi Lulian,
Thank you for using Essential XlsIO.
We support editing various properties of Legend Entries as shown in the following code snippet.
//Editing various properties of legend entries
chart.Legend.TextArea.Size = 8.25f;
chart.Legend.TextArea.FontName = "Arial";
chart.Legend.TextArea.Bold = true;
chart.Legend.TextArea.Color = ExcelKnownColors.Dark_red;
<\code>
I am sorry to say, but we dont have any method that can be used to resize the legend.
For more information on working with charts using Essential XlsIO, you can refer following links.
http://samples.syncfusion.com/ASPNET/7.3.0.20/web/XlsIO.Web/samples/3.5/Charts/EmbeddedChart/cs/embeddedchart.aspx
http://samples.syncfusion.com/ASPNET/7.3.0.20/web/XlsIO.Web/samples/3.5/Charts/ChartWorksheet/Cs/chartworksheet.aspx
Please let me know if you have any further questions.
Regards,
Vijesh