'''' This code is part of Document Solutions for PDF .NET demos.'' Copyright (c) MESCIUS inc. All rights reserved.''Imports System.IOImports System.DrawingImports System.NumericsImports GrapeCity.Documents.PdfImports GrapeCity.Documents.Pdf.AnnotationsImports GrapeCity.Documents.Pdf.GraphicsImports GrapeCity.Documents.DrawingImports GCDRAW = GrapeCity.Documents.Drawing
'' 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    Function CreatePDF(ByVal stream As Stream) As Integer        Dim doc = New GcPdfDocument()
        '' Load an existing PDF to which we will add a stamp annotation        '' (see LoadPDF for details on loading documents):        Dim jsFile = Path.Combine("Resources", "PDFs", "The-Rich-History-of-JavaScript.pdf")        Using fs = New FileStream(jsFile, FileMode.Open, FileAccess.Read)            doc.Load(fs)            Dim rect = New RectangleF(PointF.Empty, doc.Pages(0).Size)
            '' Create a FormXObject to use as the stamp appearance:            Dim 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):            Dim img = GCDRAW.Image.FromFile(Path.Combine("Resources", "ImagesBis", "draft-copy-450x72.png"))            Dim center = New Vector2(fxo.Bounds.Width / 2, fxo.Bounds.Height / 2)            fxo.Graphics.Transform =                Matrix3x2.CreateRotation((-55 * Math.PI) / 180.0F, center) *                Matrix3x2.CreateScale(6, center)            fxo.Graphics.DrawImage(img, fxo.Bounds, Nothing, ImageAlign.CenterImage)
            '' Loop over pages, add a stamp to each page:            For Each page In doc.Pages                '' Create a StampAnnotation over the whole page:                Dim stamp = New StampAnnotation() With                    {                        .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            Next            ''            doc.Save(stream)        End Using        '' Done:        Return doc.Pages.Count    End FunctionEnd Class