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Set Initial Zoom Level of the Generated PDF Document

EVO PDF Client for .NET Core

EVO HTML to PDF Converter can set the location in a PDF page where to go when the generated PDF is opened in a PDF viewer using a PdfActionGoTo object which can be assigned to DocumentOpenAction property. Additionally you can set the initial zoom level using the ExplicitDestinationZoomPercentage property of destination object used to construct the PdfActionGoTo object.

Code Sample - Set Initial Zoom Level of the Generated PDF Document

C#
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Http;

// Use EVO PDF Namespace
using EvoPdfClient;

namespace EvoHtmlToPdfDemo.Controllers.HTML_to_PDF.PDF_Viewer_Preferences
{
    public class Set_Initial_Zoom_LevelController : Controller
    {
        [HttpPost]
        public ActionResult ConvertHtmlToPdf(IFormCollection collection)
        {
            // Get the server options
            string serverIP = collection["textBoxServerIP"];
            uint serverPort = uint.Parse(collection["textBoxServerPort"]);
            string servicePassword = collection["textBoxServicePassword"];
            bool useServicePassword = servicePassword.Length > 0;
            bool useTcpService = collection["ServerType"] == "radioButtonUseTcpService";
            string webServiceUrl = collection["textBoxWebServiceUrl"];

            // Create the HTML to PDF converter object
            HtmlToPdfConverter htmlToPdfConverter = null;
            if (useTcpService)
                htmlToPdfConverter = new HtmlToPdfConverter(serverIP, serverPort);
            else
                htmlToPdfConverter = new HtmlToPdfConverter(true, webServiceUrl);

            // Set optional service password
            if (useServicePassword)
                htmlToPdfConverter.ServicePassword = servicePassword;

            // Set license key received after purchase to use the converter in licensed mode
            // Leave it not set to use the converter in demo mode
            htmlToPdfConverter.LicenseKey = "4W9+bn19bn5ue2B+bn1/YH98YHd3d3c=";

            // Set an adddional delay in seconds to wait for JavaScript or AJAX calls after page load completed
            // Set this property to 0 if you don't need to wait for such asynchcronous operations to finish
            htmlToPdfConverter.ConversionDelay = 2;

            // Convert a HTML page to a PDF document object
            Document pdfDocument = htmlToPdfConverter.ConvertUrlToPdfDocumentObject(collection["urlTextBox"]);

            int goToPageNumber = int.Parse(collection["pageNumberTextBox"]);

            // Get destination PDF page
            PdfPage goToPage = pdfDocument.GetPage(goToPageNumber - 1);

            // Get the destination point in PDF page
            float goToX = float.Parse(collection["xLocationTextBox"]);
            float goToY = float.Parse(collection["yLocationTextBox"]);

            PointFloat goToLocation = new PointFloat(goToX, goToY);

            // Get the destination view mode
            DestinationViewMode viewMode = SelectedViewMode(collection["viewModeComboBox"]);

            // Create the destination in PDF document
            ExplicitDestination goToDestination = new ExplicitDestination(goToPage, goToLocation, viewMode);

            // Set the zoom level when the destination is displayed
            if (viewMode == DestinationViewMode.XYZ)
                goToDestination.ZoomPercentage = int.Parse(collection["zoomLevelTextBox"]);

            // Set the document Go To open action
            pdfDocument.OpenAction = new PdfActionGoTo(goToDestination);

            // Save the PDF document in a memory buffer
            byte[] outPdfBuffer = pdfDocument.Save();

            // Send the PDF file to browser
            FileResult fileResult = new FileContentResult(outPdfBuffer, "application/pdf");
            fileResult.FileDownloadName = "Set_Initial_Zoom_Level.pdf";

            return fileResult;
        }

        private DestinationViewMode SelectedViewMode(string selectedValue)
        {
            switch (selectedValue)
            {
                case "X, Y and Zoom":
                    return DestinationViewMode.XYZ;
                case "Fit Window":
                    return DestinationViewMode.Fit;
                case "Fit Horizontally":
                    return DestinationViewMode.FitH;
                case "Fit Vertically":
                    return DestinationViewMode.FitV;
                default:
                    return DestinationViewMode.XYZ;
            }
        }
    }
}