Convert HTML to Raster Image

EVO PDF Client for .NET Core

EVO HTML to PDF Converter also allows you to easily convert in just a few lines of code HTML pages and HTML strings to raster images in PNG, JPG or BMP format. In this section you can learn about the basic settings of the converter.

You can choose the HTML document to convert which can be:

The basic options you can set are grouped in a few categories.

HTML Viewer Options

  • HTML Viewer Width. This option is the equivalent in converter of the browser window width. The property you can set in your code to control the browser window width is HtmlToImageConverterHtmlViewerWidth. When the browser window width is changed the HTML content displayed inside the window can have a different layout and something similar happens when you change the HTML Viewer width of the converter. At a given viewer width, the converter will capture by default the whole height of the HTML content, but you can set the HTML Viewer height to capture only the top part of the HTML page

  • HTML Viewer Height. This option is the equivalent in converter of the browser window height and can be used to limit the conversion to the top part of the HTML page. If this property is not set the entire page will be converted. The property you can set in your code to control the browser window height is HtmlToImageConverterHtmlViewerHeight

Image Options

Navigation Options

Code Sample - Convert HTML to Raster Image

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.HTML_to_Image
    public class Convert_HTML_to_ImageController : Controller
        public ActionResult ConvertHtmlToImage(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 Image converter object
            HtmlToImageConverter htmlToImageConverter = null;
            if (useTcpService)
                htmlToImageConverter = new HtmlToImageConverter(serverIP, serverPort);
                htmlToImageConverter = new HtmlToImageConverter(true, webServiceUrl);

            // Set optional service password
            if (useServicePassword)
                htmlToImageConverter.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
            htmlToImageConverter.LicenseKey = "4W9+bn19bn5ue2B+bn1/YH98YHd3d3c=";

            // Set HTML Viewer width in pixels which is the equivalent in converter of the browser window width
            htmlToImageConverter.HtmlViewerWidth = int.Parse(collection["htmlViewerWidthTextBox"]);

            // Set HTML viewer height in pixels to convert the top part of a HTML page 
            // Leave it not set to convert the entire HTML
            if (collection["htmlViewerHeightTextBox"][0].Length > 0)
                htmlToImageConverter.HtmlViewerHeight = int.Parse(collection["htmlViewerHeightTextBox"]);

            // Set if the created image has a transparent background
            htmlToImageConverter.TransparentBackground = SelectedImageFormat(collection["imageFormatComboBox"]) == ImageType.Png ? collection["transparentBackgroundCheckBox"].Count > 0 : false;

            // Set the maximum time in seconds to wait for HTML page to be loaded 
            // Leave it not set for a default 60 seconds maximum wait time
            htmlToImageConverter.NavigationTimeout = int.Parse(collection["navigationTimeoutTextBox"]);

            // 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
            if (collection["conversionDelayTextBox"][0].Length > 0)
                htmlToImageConverter.ConversionDelay = int.Parse(collection["conversionDelayTextBox"]);

            byte[][] imageTiles = null;

            if (collection["HtmlPageSource"] == "convertUrlRadioButton")
                string url = collection["urlTextBox"];

                // Convert the HTML page given by an URL to a set of Image objects
                imageTiles = htmlToImageConverter.ConvertUrlToImageTiles(url, SelectedImageFormat(collection["imageFormatComboBox"]));
                string htmlString = collection["htmlStringTextBox"];
                string baseUrl = collection["baseUrlTextBox"];

                // Convert a HTML string with a base URL to a set of Image objects
                imageTiles = htmlToImageConverter.ConvertHtmlToImageTiles(htmlString, baseUrl, SelectedImageFormat(collection["imageFormatComboBox"]));

            // Save the first image tile to a memory buffer

            byte[] outImageBuffer = imageTiles[0];

            string imageFormatName = collection["imageFormatComboBox"][0].ToLower();

            // Send the image file to browser
            FileResult fileResult = new FileContentResult(outImageBuffer, "image/" + (imageFormatName == "jpg" ? "jpeg" : imageFormatName));
            fileResult.FileDownloadName = "HTML_to_Image." + imageFormatName;

            return fileResult;

        private ImageType SelectedImageFormat(string selectedValue)
            switch (selectedValue)
                case "Png":
                    return ImageType.Png;
                case "Jpg":
                    return ImageType.Jpeg;
                case "Bmp":
                    return ImageType.Bmp;
                    return ImageType.Png;