'''' This code is part of Document Solutions for PDF .NET demos.'' Copyright (c) MESCIUS inc. All rights reserved.''Imports System.IOImports System.DrawingImports GrapeCity.Documents.PdfImports GrapeCity.Documents.Pdf.StructureImports GrapeCity.Documents.Pdf.MarkedContentImports GCTEXT = GrapeCity.Documents.Text
'' This sample shows how to create a PDF/UA-2 (accessible) compliant document.Public Class PdfUa2    Function CreatePDF(ByVal stream As Stream) As Integer        Dim doc = New GcPdfDocument()
        '' PDF/UA-2 is based on PDF 2.0:        doc.PdfVersion = "2.0"        '' The document language must be specified for PDF/UA:        doc.Lang = "en"        '' Mark the document as PDF/UA-2 conformant:        doc.Metadata.PdfUa = 2        '' PDF/UA-2 requires the "revision" year of the ISO 14289-2:2024 standard itself (not the document's date):        doc.Metadata.PdfUaRev = "2024"        doc.Metadata.Title = "PDF/UA-2 compliant document"        doc.ViewerPreferences.DisplayDocTitle = True        '' Mark the document as conforming to Tagged PDF conventions (required for PDF/UA):        doc.MarkInfo.Marked = True
        Dim fnt = GCTEXT.Font.FromFile(Path.Combine("Resources", "Fonts", "NotoSans-Regular.ttf"))
        '' PDF/UA-2 requires the structure tree to declare the namespaces it uses.        '' Add the standard PDF 2.0 structure namespace:        Dim ns = New [Namespace]("http://iso.org/pdf2/ssn")        doc.StructTreeRoot.Namespaces.Add(ns)
        '' PDF/UA-2 requires a "Document" structure element as the root of the structure tree,        '' associated with the namespace declared above:        Dim seDocument = New StructElement("Document") With {.NS = ns}        doc.StructTreeRoot.Children.Add(seDocument)
        Const chapterCount = 3        For i = 0 To chapterCount - 1            Dim page = doc.Pages.Add()            Dim g = page.Graphics            Dim headingTop = 72.0F
            If i = 0 Then                '' Structure Destinations are a very new PDF 2.0 mechanism - at the time of writing,                '' neither the DsPdfViewer used in these demos, nor Adobe Acrobat, resolve them yet,                '' so clicking a bookmark below may not navigate to its heading even though the                '' destination itself is generated correctly (per the PDF/UA-2 and PDF 2.0 specs).                '' This note is not part of the document's real content, so it is drawn using the                '' already-embedded font (PDF/UA-2 requires every font used for rendering - including                '' the standard 14 fonts - to be embedded) and marked as a layout artifact rather than                '' tagged content (PDF/UA-2 requires all content to be either tagged or an artifact):                Dim tlNote = g.CreateTextLayout()                tlNote.DefaultFormat.Font = fnt                tlNote.DefaultFormat.FontSize = 12                tlNote.MarginAll = 72                tlNote.MaxWidth = page.Size.Width                tlNote.Append(                    "This document's outline (bookmarks) use PDF 2.0 ""Structure Destinations"" to point directly at each " &                    "chapter heading below, as required by PDF/UA-2. Neither the DsPdfViewer used in these demos, nor " &                    "Adobe Acrobat, currently resolve this new destination type, so clicking a bookmark may not navigate " &                    "to the target heading, even though the destination itself is generated correctly.")                tlNote.PerformLayout(True)
                Dim noteRect = tlNote.ContentRectangle                noteRect.Inflate(9, 9)
                g.BeginMarkedContent(New TagArtifact With {.Type = TagArtifact.Types.TypeLayout})                g.FillRectangle(noteRect, Color.FromArgb(213, 221, 240))                g.DrawRectangle(noteRect, Color.FromArgb(59, 92, 170), 0.5F)                g.DrawTextLayout(tlNote, PointF.Empty)                g.EndMarkedContent()
                headingTop = noteRect.Bottom + 24            End If
            '' Chapter heading, tagged as a top-level "H1" element under the Document root:            Dim seHeading = New StructElement("H1") With {.DefaultPage = page}            seDocument.Children.Add(seHeading)
            Dim tlHeading = g.CreateTextLayout()            tlHeading.MarginAll = 72            tlHeading.MarginTop = headingTop            tlHeading.MaxWidth = page.Size.Width            tlHeading.DefaultFormat.Font = fnt            tlHeading.DefaultFormat.FontBold = True            tlHeading.DefaultFormat.FontSize = 20            tlHeading.Append($"Chapter {i + 1}")
            g.BeginMarkedContent(New TagMcid("H1", 0))            g.DrawTextLayout(tlHeading, PointF.Empty)            g.EndMarkedContent()            seHeading.ContentItems.Add(New McidContentItemLink(0))
            '' Chapter body, tagged as a "P" element under the same Document root:            Dim seParagraph = New StructElement("P") With {.DefaultPage = page}            seDocument.Children.Add(seParagraph)
            Dim tlBody = g.CreateTextLayout()            tlBody.MarginAll = 72            tlBody.MarginTop = tlHeading.ContentRectangle.Bottom + 24            tlBody.MaxWidth = page.Size.Width            tlBody.DefaultFormat.Font = fnt            tlBody.DefaultFormat.FontSize = 12            tlBody.Append(Util.LoremIpsum(3, 2, 5))
            g.BeginMarkedContent(New TagMcid("P", 1))            g.DrawTextLayout(tlBody, PointF.Empty)            g.EndMarkedContent()            seParagraph.ContentItems.Add(New McidContentItemLink(1))
            '' Add an outline entry for this chapter using a "Structure Destination" - one that points            '' at the heading's structure element rather than a page/coordinate pair, as required by            '' PDF/UA-2 (see PDF 2.0 spec, 12.3.2.3 "Structure Destinations"):            doc.Outlines.Add(New OutlineNode($"Chapter {i + 1}", New DestinationFitBV(seHeading, Nothing)))        Next
        doc.Save(stream)        Return doc.Pages.Count    End FunctionEnd Class