Hi Magnus,
Thank you for being patient.
Isn't it possible to have the chartarea and plotarea transparent?It is possible to set the Chartarea and Plotarea be transparent. Please refer the below code:
//Set colors for chart Area
chart.ChartArea .Fill.ForeColor = Color.Transparent;
chart.ChartArea.Fill.BackColor = Color.Transparent;
//Plot Area
IChartFrameFormat chartPlotArea = chart.PlotArea;
//Set colors for plot area
chartPlotArea.Fill.ForeColor = Color.Transparent;
chartPlotArea.Fill.BackColor = Color.Transparent;
Also, Please refer the sample in the below link which illustrates the above:
http://websamples.syncfusion.com/samples/XlsIO.Windows/70826/main.htmPlease let me know if you have any concerns.
Regards,
Yavana.G