Extract Images from PDF

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

using HiQPdfClient;

namespace HiQPdf_Demo.Controllers
{
    public class ExtractImagesFromPdfController : Controller
    {
        IWebHostEnvironment m_hostingEnvironment;
        public ExtractImagesFromPdfController(IWebHostEnvironment hostingEnvironment)
        {
            m_hostingEnvironment = hostingEnvironment;
        }

        // GET: ExtractImagesFromPdf
        public ActionResult Index()
        {
            SetCrtPageUri();

            return View();
        }

        [HttpPost]
        public ActionResult ExtractImages(IFormCollection collection)
        {
            string serverIP = collection["textBoxServerIP"];
            uint serverPort = uint.Parse(collection["textBoxServerPort"]);
            string serverPassword = collection["textBoxServerPassword"];

            // get the PDF file
            string pdfFile = m_hostingEnvironment.WebRootPath + "/DemoFiles/Pdf/InputPdf.pdf";

            // create the PDF images extractor
            PdfImagesExtract pdfImagesExtract = new PdfImagesExtract(serverIP, serverPort);

            // use server password if necessary
            if (serverPassword.Length > 0)
                pdfImagesExtract.ServerPassword = serverPassword;

            // set a demo serial number
            pdfImagesExtract.SerialNumber = "YCgJMTAE-BiwJAhIB-EhlWTlBA-UEBRQFBA-U1FOUVJO-WVlZWQ==";

            int fromPdfPageNumber = int.Parse(collection["textBoxFromPage"]);
            int toPdfPageNumber = collection["textBoxToPage"][0].Length > 0 ? int.Parse(collection["textBoxToPage"]) : 0;

            // extract the images from PDF document to memory in .NET Image objects
            // the images can also be extracted to a folder using the ExtractToImageFiles method 
            // or they can be extracted one by one using the RaiseImageExtractedEvent method
            ExtractedPdfImage[] extractedImages = pdfImagesExtract.ExtractToImageObjects(pdfFile, fromPdfPageNumber, toPdfPageNumber);

            // return if no image was extracted
            if (extractedImages.Length == 0)
                return Redirect("/ExtractImagesFromPdf");

            // get the largest image bytes in a buffer
            byte[] imageBuffer = null;
            try
            {
                // select the largest image
                ExtractedPdfImage largestImage = null;
                for (int i = 0; i < extractedImages.Length; i++)
                {
                    if (largestImage == null || extractedImages[i].ImageData.Length > largestImage.ImageData.Length)
                    {
                        largestImage = extractedImages[i];
                    }
                }

                // get the image data in a buffer
                imageBuffer = GetImageBuffer(largestImage);
            }
            finally
            {
                // dispose the extracted images
                for (int i = 0; i < extractedImages.Length; i++)
                    extractedImages[i].Dispose();
            }

            FileResult fileResult = new FileContentResult(imageBuffer, "image/png");
            fileResult.FileDownloadName = "ExtractedImage.png";

            return fileResult;
        }

        private byte[] GetImageBuffer(ExtractedPdfImage extractedImage)
        {
            byte[] imageBuffer = new byte[extractedImage.ImageData.Length];
            Array.Copy(extractedImage.ImageData, imageBuffer, imageBuffer.Length);

            return imageBuffer;
        }

        private void SetCrtPageUri()
        {
            HttpRequest httpRequest = this.ControllerContext.HttpContext.Request;
            UriBuilder uriBuilder = new UriBuilder();
            uriBuilder.Scheme = httpRequest.Scheme;
            uriBuilder.Host = httpRequest.Host.Host;
            if (httpRequest.Host.Port != null)
                uriBuilder.Port = (int)httpRequest.Host.Port;
            uriBuilder.Path = httpRequest.PathBase.ToString() + httpRequest.Path.ToString();
            uriBuilder.Query = httpRequest.QueryString.ToString();

            ViewData["CrtPageUri"] = uriBuilder.Uri.AbsoluteUri;
        }
    }
}