HTML to Image Converter Overview

using System.ComponentModel.DataAnnotations;
using Microsoft.AspNetCore.Mvc;
using HiQPdf_Next_AspNetDemo.Models;

using HiQPdf.Next;

namespace HiQPdf_Next_AspNetDemo.Controllers
{
    public class ConvertHtmlToImageController : Controller
    {
        // GET: ConvertHtmlToImage
        public ActionResult Index()
        {
            var model = new ConvertHtmlToImageViewModel();
            return View(model);
        }

        [HttpPost]
        public ActionResult ConvertToImage(ConvertHtmlToImageViewModel model)
        {
            if (!ModelState.IsValid)
            {
                var errorMessage = ModelStateHelper.GetModelErrors(ModelState);
                throw new ValidationException(errorMessage);
            }

            // Replace the demo serial number with the serial number received upon purchase
            // to run the converter in licensed mode
            Licensing.SerialNumber = "YCgJMTAE-BiwJAhIB-EhlWTlBA-UEBRQFBA-U1FOUVJO-WVlZWQ==";

            // create the HTML to Image converter
            HtmlToImage htmlToImageConverter = new HtmlToImage();

            // set browser width
            htmlToImageConverter.BrowserWidth = model.BrowserWidth;

            // set browser height if specified, otherwise use the default
            if (model.BrowserHeight.HasValue)
                htmlToImageConverter.BrowserHeight = model.BrowserHeight.Value;

            // enable the conversion of the entire page, not only the viewport defined by BrowserWidth and BrowserHeight
            htmlToImageConverter.ConvertEntirePage = model.ConvertEntirePage;

            // set the loading mode used to convert the entire page content
            htmlToImageConverter.ConvertEntirePageMode = model.ConvertEntirePageMode == "Browser" ?
                ConvertEntirePageMode.Browser : ConvertEntirePageMode.Custom;

            // optionally auto resize HTML viewer height at the HTML content size determined after the initial loading
            htmlToImageConverter.AutoResizeBrowserHeight = model.AutoResizeViewerHeight;

            // set wait time before starting conversion
            htmlToImageConverter.WaitBeforeConvert = model.WaitTime;

            // set HTML Load timeout
            htmlToImageConverter.HtmlLoadedTimeout = model.LoadHtmlTimeout;

            // the image buffer in the selected image format
            byte[] imageBuffer = null;
            ImageType imageType = GetSelectedImageFormat(model.ImageFormat);

            if (model.UrlOrHtmlCode == "ConvertUrl")
            {
                // convert URL
                string url = model.Url;

                imageBuffer = htmlToImageConverter.ConvertUrlToMemory(url, imageType);
            }
            else
            {
                // convert HTML code
                string htmlCode = model.HtmlCode;
                string baseUrl = model.BaseUrl;

                imageBuffer = htmlToImageConverter.ConvertHtmlToMemory(htmlCode, baseUrl, imageType);
            }

            // inform the browser about the binary data format
            string imageFileExtension = GetImageFileExtension(imageType);
            string imageFileName = string.Format("HtmlToImage.{0}", imageFileExtension);

            string mimeType = GetImageMimeType(imageType);
            FileResult fileResult = new FileContentResult(imageBuffer, "image/" + mimeType);
            fileResult.FileDownloadName = imageFileName;

            return fileResult;
        }

        private string GetImageMimeType(ImageType imageType)
        {
            switch (imageType)
            {
                case ImageType.Png:
                    return "png";
                case ImageType.Jpeg:
                    return "jpeg";
                case ImageType.Webp:
                    return "webp";
                default:
                    return "png";
            }
        }

        private string GetImageFileExtension(ImageType imageType)
        {
            switch (imageType)
            {
                case ImageType.Png:
                    return "png";
                case ImageType.Jpeg:
                    return "jpg";
                case ImageType.Webp:
                    return "webp";
                default:
                    return "png";
            }
        }

        private ImageType GetSelectedImageFormat(string imageFormat)
        {
            switch (imageFormat)
            {
                case "PNG":
                    return ImageType.Png;
                case "JPG":
                    return ImageType.Jpeg;
                case "WEBP":
                    return ImageType.Webp;
                default:
                    return ImageType.Png;
            }
        }
    }
}