Chart conversion to bytes

[Nicolas]

Hi, I looked into all export options for the charts, and I saw nothing to convert the chart as an image or bytes via a stream. I would like to avoid the creation of an intermediatefile. Thanks in advance! - Nicolas

[Anandaraj T]

Hi Nicolas, 

Thanks for using Syncfusion products. 

We can use the Draw method of chart control to draw chart in an Image or Bitmap object. We can convert this Image object to a stream or byte array as required. 

We have prepared a sample for this requirement and it can be downloaded from the following link 

http://www.syncfusion.com/downloads/support/forum/126440/ze/ChartExportDemo-609256266 

Please refer the following code snippet to achieve this 

[C#] 

 

            //Draw chart in an Image or Bitmap object 

            Image img = new Bitmap(this.chartControl1.Width, this.chartControl1.Height);             

            this.chartControl1.Draw(img); 

 

            //Convert image to stream 

            Stream stream = new MemoryStream(); 

            img.Save(stream, ImageFormat.Png); 

             

            //Convert stream to bytes 

            byte[] chartBytes = new byte[stream.Length]; 

            stream.Write(chartBytes, 0, chartBytes.Length); 

 

            //For verifying the exported image. 

            img.Save("Chart.png"); 

 

            //Dispose image and stream 

            img.Dispose(); 

            stream.Dispose(); 

 

Please let us know if you have any concern. 

Regards, 

Anand

[Nicolas]

Hi, still not working on my side, have you tried to convert back the bytes to image? My side it's returning nothing - Thanks in advance, Nicolas

[Anandaraj T]

Hi Nicolas, 

Sorry for the inconvenience caused. 

In our previous sample, stream was not converted to bytes properly. On further analysis, we found that stream was not positioned to 0 before copying it to a byte array. We can either use Read method or ToArray method of MemoryStream to copy the stream contents to a byte array. 

Note: ToArray method is available only for MemoryStream object and not for Stream object. When using Read method, set the position of stream to 0. 

We have modified the sample and it can be downloaded from the following link 

http://www.syncfusion.com/downloads/support/directtrac/126440/ze/ChartExportDemo-1553640136 

Please refer the following code snippet to achieve this 

[C#] 

 

            //Draw chart in an Image or Bitmap object 

            Image img = new Bitmap(this.chartControl1.Width, this.chartControl1.Height);             

            this.chartControl1.Draw(img); 

 

            //Convert image to memory stream 

            MemoryStream stream = new MemoryStream(); 

            img.Save(stream, ImageFormat.Png); 

             

            //Convert memory stream to bytes 

            byte[] chartBytes = stream.ToArray(); 

 

            //For verifying the exported image. 

            stream.Dispose(); 

            img.Dispose(); 

             

            stream = new MemoryStream(chartBytes); 

            img = Image.FromStream(stream); 

            img.Save("Chart.png"); 

 

            //Dispose image and stream 

            img.Dispose(); 

            stream.Dispose(); 

 

Please let us know if you have any concern. 

Regards, 

Anand 

[Nicolas]

Hi! Now it's working good! Thank you! One more question if you do not mind, when the render is made, apparently the OnChartControl1_ChartFormatAxisLabel which is there to apply a custom format on the label is not working. On screen, I can see the chart with the proper labels, but once streamed, those labels are replaced with the original numeric values - Thank you in advance! - Nicolas

[Anandaraj T]

Hi Nicolas, 

Thanks for the update. 

The reported issue is fixed in the latest version of Essential Studio (Volume 3, 2016). We request you to upgrade to the latest version. 

Please let us know if you need further assistance on this. 

Regards, 

Anand 

[Nicolas]

All good now, thanks! - Nicolas

[Preethi Nesakkan Gnanadurai]

Hi Nicolas,  

  

Most Welcome. 

  

Please let us know if you need any further assistance. 

  

Regards,  

Preethi