//// This code is part of Document Solutions for PDF .NET demos.// Copyright (c) MESCIUS inc. All rights reserved.//using System;using System.IO;using System.Drawing;using GrapeCity.Documents.Pdf;using GrapeCity.Documents.Drawing;using GrapeCity.Documents.Pdf.Annotations;using GrapeCity.Documents.Pdf.Graphics;using System.Numerics;using GCTEXT = GrapeCity.Documents.Text;using GCDRAW = GrapeCity.Documents.Drawing;
namespace DsPdfWeb.Demos.Basics{    // This sample demonstrates how to add a custom appearance stream    // to an annotation using a FormXObject.    // We load an existing PDF and then loop over its pages.    // On each page we create a StampAnnotation and a FormXObject    // which is assigned to the annotation's normal default appearance stream.    // A semi-transparent PNG image representing the stamp is then drawn    // on the FormXObject's Graphics using Transform and DrawImage methods.    public class StampImage    {        public int CreatePDF(Stream stream)        {            var doc = new GcPdfDocument();            // Load an existing PDF to which we will add a stamp annotation            // (see LoadPDF for details on loading documents):            var jsFile = Path.Combine("Resources", "PDFs", "The-Rich-History-of-JavaScript.pdf");            using var fs = File.OpenRead(jsFile);            doc.Load(fs);            var rect = new RectangleF(PointF.Empty, doc.Pages[0].Size);            // Create a FormXObject to use as the stamp appearance:            var fxo = new FormXObject(doc, rect);            // Get an image from the resources, and draw it on the FormXObject's graphics            // (see Transformations for details on using GcGraphics.Transform):            using var image = GCDRAW.Image.FromFile(Path.Combine("Resources", "ImagesBis", "draft-copy-450x72.png"));            var center = new Vector2(fxo.Bounds.Width / 2, fxo.Bounds.Height / 2);            fxo.Graphics.Transform =                Matrix3x2.CreateRotation((float)(-55 * Math.PI) / 180f, center) *                Matrix3x2.CreateScale(6, center);            fxo.Graphics.DrawImage(image, fxo.Bounds, null, ImageAlign.CenterImage);            // Loop over pages, add a stamp to each page:            foreach (var page in doc.Pages)            {                // Create a StampAnnotation over the whole page:                var stamp = new StampAnnotation()                {                    Icon = StampAnnotationIcon.Draft.ToString(),                    Name = "draft",                    Page = page,                    Rect = rect,                    UserName = "Jaime Smith"                };                // Re-use the same FormXObject on all pages:                stamp.AppearanceStreams.Normal.Default = fxo;            }            // Done:            doc.Save(stream);            return doc.Pages.Count;        }    }}