//
// 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 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.
    // In the sample, an existing PDF is loaded, and then we loop over
    // the document's pages. On each page, a StampAnnotation is created, and a FormXObject
    // which is assigned to the annotation's normal default appearance stream.
    // A semi-transparent PNG image is then drawn on the FormXObject's
    // Graphics using regular GcGraphics features (Transform and DrawImage).
    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;
        }
    }
}