DPL Processing

You can configure the PDFViewer to use the Telerik Document Processing library for PDF processing.

DPL Processing is in its beta version and has the following limitations:

• The clipping of elements and gradients is currently not supported.
• SVG or encoded images in other formats might not render correctly.

Requirements

• DPL Processing depends on the Telerik.Web.PDF assembly.
• To use DPL Processing, the application must target .NET Standard 2.0.
• The Read() option is mandatory.

Basic Configuration

The following example demonstrates how to configure the PDFViewer to use DPL Processing.

Razor

@(Html.Kendo().PDFViewer()
    .Name("pdfviewer")
    .DplProcessing(dpl => {
        dpl.Read(r => r.Url(Url.Action("GetInitialPdf", "PDFViewer")));
        dpl.Upload(upload => upload.Url(Url.Action("GetPdf", "PDFViewer")).SaveField("file"));
        dpl.LoadOnDemand(true);
    })
    .Toolbar(toolbar =>
        toolbar.Items(items =>
        {
            items.Add().Command("PageChangeCommand").Type("pager").Name("pager");
            items.Add().Name("spacer").Type("spacer");
            items.Add().Command("OpenCommand").Type("button").Name("open").Icon("folder-open");
        })
    )
    .Height(1200)
)

Razor

@addTagHelper *, Kendo.Mvc

<kendo-pdfviewer name="pdfviewer" height="1200">
    <dpl-processing load-on-demand="true">
        <read url="@Url.Action("GetInitialPdf","PDFViewer")" />
        <upload url="@Url.Action("GetPdf","PDFViewer")" save-field="file" />
    </dpl-processing>
    <toolbar enabled="true">
        <pdfviewer-toolbar-items>
            <pdfviewer-toolbar-item name="pager" command="PageChangeCommand" type="pager"></pdfviewer-toolbar-item>
            <pdfviewer-toolbar-item name="spacer" type="spacer"></pdfviewer-toolbar-item>
            <pdfviewer-toolbar-item name="open"
                command="OpenCommand" 
                type="button"
                icon="folder-open">
            </pdfviewer-toolbar-item>
        </pdfviewer-toolbar-items>
    </toolbar>
</kendo-pdfviewer>

C#

using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
using System.IO;
using Telerik.Web.PDF;

namespace ProjectName.Controllers
{
    public class PDFViewerController : Controller
    {
        public IActionResult GetInitialPdf(int? pageNumber)
        {
            JsonResult jsonResult;
            byte[] file = System.IO.File.ReadAllBytes($"wwwroot{Path.DirectorySeparatorChar}App_Data{Path.DirectorySeparatorChar}sample.pdf");
            FixedDocument doc = FixedDocument.Load(file, true);

            if (pageNumber == null)
            {
                jsonResult = Json(doc.ToJson());
            }
            else
            {
                jsonResult = Json(doc.GetPage((int)pageNumber));
            }

            return jsonResult;
        }

        [HttpPost]
        public IActionResult GetPdf(IFormFile file)
        {
            byte[] data;
            using (Stream inputStream = file.OpenReadStream())
            {
                MemoryStream memoryStream = inputStream as MemoryStream;
                if (memoryStream == null)
                {
                    memoryStream = new MemoryStream();
                    inputStream.CopyTo(memoryStream);
                }
                data = memoryStream.ToArray();
            }
            FixedDocument dox = FixedDocument.Load(data);
            return Json(dox.ToJson());
        }
    }
}

Starting with version 2024 Q4, the FixedDocument.Load and FixedDocument.Download methods and their overloads accept an additional, optional parameter—TimeSpan timeOut. The parameter indicates the timeout for the operation and defaults to 1 minute.

See Also

• DPL Processing by the PDFViewer HtmlHelper for ASP.NET Core (Demo)
• Server-Side API
• Server-Side TagHelper API