GetImages.cs
//
// This code is part of Document Solutions for PDF demos.
// Copyright (c) MESCIUS inc. All rights reserved.
//
using System;
using System.IO;
using System.Drawing;
using System.Text;
using GrapeCity.Documents.Pdf;
using GrapeCity.Documents.Text;
using GrapeCity.Documents.Drawing;

namespace DsPdfWeb.Demos
{
    // This sample loads a PDF (we use the document generated by the Wetlands sample)
    // and extracts all images from it. It then prints those images into a new PDF,
    // centered one per page.
    public class GetImages
    {
        public int CreatePDF(Stream stream)
        {
            var tf = new TextFormat() { Font = StandardFonts.Times, FontSize = 12 };
            using (var fs = File.OpenRead(Path.Combine("Resources", "PDFs", "Wetlands.pdf")))
            {
                var docSrc = new GcPdfDocument();
                // Load an existing PDF with some images:
                docSrc.Load(fs);
                // This call extracts information about images from the loaded PDF,
                // note that for large files it may take a while to complete:
                var imageInfos = docSrc.GetImages();

                var doc = new GcPdfDocument();
                var textPt = new PointF(72, 72);
                var imageRc = new RectangleF(72, 72 * 2, doc.PageSize.Width - 72 * 2, doc.PageSize.Height - 72 * 3);

                foreach (var imageInfo in imageInfos)
                {
                    // The same image may appear on multiple locations, 
                    // imageInfo includes page indices and locations on pages;
                    // for simplicity sake we only print page numbers here:
                    var sb = new StringBuilder();
                    imageInfo.Locations.ForEach(il_ => sb.Append((il_.Page.Index + 1).ToString() + ", "));
                    var g = doc.NewPage().Graphics;
                    g.DrawString($"This image appears on page(s) {sb.ToString().TrimEnd(' ', ',')} of the original PDF:", tf, new PointF(72, 72));
                    g.DrawImage(imageInfo.Image, imageRc, null, ImageAlign.ScaleImage);
                }
                // Done:
                doc.Save(stream);
                return doc.Pages.Count;
            }
        }
    }
}