//// This code is part of Document Solutions for PDF .NET demos.// Copyright (c) MESCIUS inc. All rights reserved.//using System.IO;using System.Drawing;using System.Collections.Generic;using GrapeCity.Documents.Pdf;using GrapeCity.Documents.Pdf.Graphics.Images;using GrapeCity.Documents.Pdf.Spec;using GrapeCity.Documents.Text;
namespace DsPdfWeb.Demos{    // This example shows how to fetch low level information about images living in a PDF file,    // such as the ID of the image object in the PDF, the filter used to store the image,    // the decoder parameters, the content of the PdfImage dictionary, etc.    // The original PDF is appended to the result for reference.    public class GetImageProperties    {        public int CreatePDF(Stream stream)        {            using var fs = File.OpenRead(Path.Combine("Resources", "PDFs", "Wetlands.pdf"));            var docSrc = new GcPdfDocument();            docSrc.Load(fs);
            // Get the images in the loaded PDF and print their info into the resulting PDF:            var imageInfos = docSrc.GetImages();
            // The PDF to hold the results:            var doc = new GcPdfDocument();            var page = doc.NewPage();            // Set up a TextLayout to format the results:            var tl = page.Graphics.CreateTextLayout();            tl.DefaultFormat.Font = StandardFonts.Courier;            tl.DefaultFormat.FontSize = 14;            tl.MaxWidth = doc.PageSize.Width;            tl.MaxHeight = doc.PageSize.Height;            tl.MarginAll = tl.Resolution;            var captionFmt = new TextFormat(tl.DefaultFormat) { Font = StandardFonts.CourierBold, FontSize = tl.DefaultFormat.FontSize + 2 };
            int i = 0;            foreach (var imageInfo in imageInfos)            {                tl.AppendLine($"Image {++i}", captionFmt);
                // PdfImageBase class represents an image in the loaded PDF file:                PdfImageBase img = imageInfo.Image;
                tl.AppendLine($"PdfImage object ID: {img.ObjID}");                // PdfImageBase is derived from PdfDictWrapper type, it has methods                // that allow you to access properties/data of the underlying PDF stream object:                using (PdfStreamInfo psi = img.GetPdfStreamInfo())                {                    tl.AppendLine($"    Image stream length: {psi.Stream.Length}");                    tl.AppendLine($"        ImageFilterName: {psi.ImageFilterName}");                    tl.AppendLine($"ImageFilterDecodeParams: {psi.ImageFilterDecodeParams}");                    // Dump the content of the ImageFilterDecodeParams if it exists:                    if (psi.ImageFilterDecodeParams != null)                    {                        foreach (var kvp in psi.ImageFilterDecodeParams.Dict)                        {                            tl.AppendLine($"{kvp.Key}: {kvp.Value}");                        }                        // An example of how to get the value of BlackIs1:                        var blackIs1 = psi.ImageFilterDecodeParams.GetBool(PdfName.Std.BlackIs1, null);                        tl.AppendLine($"BlackIs1: {blackIs1}");                    }                }                // Dump the properties of PdfImage dictionary:                tl.AppendLine();                tl.AppendLine("Properties of PdfImage dictionary:");                foreach (KeyValuePair<PdfName, IPdfObject> kvp in img.PdfDict.Dict)                {                    tl.AppendLine($"{kvp.Key}: {kvp.Value}");                }                //                 var cs = img.Get<IPdfObject>(PdfName.Std.ColorSpace);                tl.AppendLine($"ColorSpace: {cs.GetType().Name} {cs}");                var bpc = img.Get<IPdfObject>(PdfName.Std.BitsPerComponent);                tl.AppendLine($"BitsPerComponent: {bpc?.GetType().Name} {bpc}");                tl.AppendLine();            }
            // Render the results:            tl.PerformLayout(true);            while (true)            {                var splitResult = tl.Split(null, out TextLayout rest);                page.Graphics.DrawTextLayout(tl, PointF.Empty);                if (splitResult != SplitResult.Split)                    break;                tl = rest;                tl.MarginTop = tl.Resolution;                page = doc.Pages.Add();            }
            // Append the source PDF to the result for reference:            doc.MergeWithDocument(docSrc);
            // Done:            doc.Save(stream);            return doc.Pages.Count;        }    }}