How to convert a PowerPoint file to PDF in Xamarin?

public class PowerPointController : ApiController
{
        /// <summary>
        /// Converts the PowerPoint to PDF document.
        /// </summary>
        [AcceptVerbs("Post")]
        public HttpResponseMessage ConvertToPdf()
        {
            HttpResponseMessage httpResponseMessage;
            using (Stream stream = Request.Content.ReadAsStreamAsync().Result)
            {
                try
                {
                    //Opens the PowerPoint from stream
                    using (IPresentation pptxDoc = Presentation.Open(stream))
                    {
                        //Initializes the ChartToImageConverter for converting charts during PowerPoint to PDF conversion
                        pptxDoc.ChartToImageConverter = new ChartToImageConverter
                        {
                            ScalingMode = Syncfusion.OfficeChart.ScalingMode.Best
                        };
 
                        //Creates an instance of the PresentationToPdfConverterSettings
                        PresentationToPdfConverterSettings settings = new PresentationToPdfConverterSettings
                        {
                            ShowHiddenSlides = true
                        };
                        //Converts PowerPoint into PDF document
                        PdfDocument pdfDocument = PresentationToPdfConverter.Convert(pptxDoc, settings);                        
                        //Saves the PDF document to response stream
                        MemoryStream memoryStream = new MemoryStream();
                        pdfDocument.Save(memoryStream);
                        memoryStream.Position = 0;
                        httpResponseMessage = new HttpResponseMessage(HttpStatusCode.OK)
                        {
                            Content = new StreamContent(memoryStream)
                        };
                        pdfDocument.Dispose();
                    }
                }
                catch
                {
                    httpResponseMessage = new HttpResponseMessage(HttpStatusCode.ExpectationFailed);
                }
            }
            return httpResponseMessage;
        }
    }

private async void PptxToPdfViewer(object sender, EventArgs e)
{
     string resourcePath = "XamarinFormsPDFConversion.Data.Template.pptx";
     Assembly assembly = typeof(MainPage).GetTypeInfo().Assembly;
     Stream stream = assembly.GetManifestResourceStream(resourcePath);
 
     //Open a PowerPoint
     IPresentation pptxDoc = Syncfusion.Presentation.Presentation.Open(stream);
 
     //Save the Presentation to stream
     MemoryStream inputStream = new MemoryStream();
     pptxDoc.Save(inputStream);
     pptxDoc.Close();
     stream.Dispose();
     inputStream.Position = 0;
     
     // Creates new instance of HttpClient to access service.
     HttpClient client = new HttpClient();
     
     // Gets Uri 
     string requestUri = "http://js.syncfusion.com/demos/ioservices/api/powerpoint/converttopdf";
     
     // Posts input PowerPoint document to service and gets resultant PDF as content of HttpResponseMessage
     HttpResponseMessage response = await client.PostAsync(requestUri, new StreamContent(inputStream));
 
     //Dispose the input stream and client instances.
     inputStream.Dispose();
     client.Dispose();
     MemoryStream outputStream = null;
 
     // Gets PDF from content stream if service got success.
     if (response.IsSuccessStatusCode)
     {
         var responseHeaders = response.Headers;
         outputStream = new MemoryStream(await response.Content.ReadAsByteArrayAsync());
 
         // Dispose the response instance.
         response.Dispose();
 
     }
 
     outputStream.Position = 0;
 
     if (Device.RuntimePlatform == Device.UWP)
           Xamarin.Forms.DependencyService.Get<ISaveWindowsPhone>().Save("ConvertedPDF.pdf", "application/pdf", outputStream);
     else
           Xamarin.Forms.DependencyService.Get<ISave>().Save("ConvertedPDF.pdf", "application/pdf", outputStream);
}

Syncfusion demo URL: 
string demoURL = “http://js.syncfusion.com/demos/ioservices/api/powerpoint/converttopdf”;