'''' 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.Text
'' Creates a multi-column text layout with balanced columns.'' The heart of this sample is the TextLayout.SplitAndBalance() method'' which allows splitting a text between multiple columns,'' AND balance those columns so that their heights are similar,'' thus allowing to produce magazine- and newspaper-like text layouts.Public Class BalancedColumns    Function CreatePDF(ByVal stream As Stream) As Integer        Dim doc = New GcPdfDocument()        Dim font = StandardFonts.Times        Dim fontSize = 12        '' 1/2" margins all around (72 dpi is the default resolution used by DsPdf):        Dim margin = 72 / 2        Dim pageWidth = doc.PageSize.Width        Dim pageHeight = doc.PageSize.Height        Dim cW = pageWidth - margin * 2        '' Text format for the chapter titles:        Dim tlCaption = New TextLayout(72)        tlCaption.DefaultFormat.Font = font        tlCaption.DefaultFormat.FontSize = fontSize + 4        tlCaption.DefaultFormat.Underline = True        tlCaption.MaxWidth = pageWidth        tlCaption.MaxHeight = pageHeight        tlCaption.MarginLeft = margin        tlCaption.MarginTop = margin        tlCaption.MarginRight = margin        tlCaption.MarginBottom = margin        tlCaption.TextAlignment = TextAlignment.Center        '' Height of chapter caption (use a const for simplicity):        Const captionH = 24.0F        '' Text layout for main document body (default DsPdf resolution is 72dpi):        Dim tl = New TextLayout(72)        tl.DefaultFormat.Font = font        tl.DefaultFormat.FontSize = fontSize        tl.FirstLineIndent = 72 / 2        tl.MaxWidth = pageWidth        tl.MaxHeight = pageHeight        tl.MarginLeft = margin        tl.MarginRight = margin        tl.MarginBottom = margin        tl.MarginTop = margin + captionH        tl.ColumnWidth = cW * 0.3F        tl.TextAlignment = TextAlignment.Justified        '' Array of PageSplitArea's which control additional columns (1st column is controlled by        '' the 'main' TextLayout, for each additional one a PageSplitArea must be provided -         '' it will create and return a TextLayout that can then be used to render the column):        Dim psas As PageSplitArea() = {            New PageSplitArea(tl) With {.MarginLeft = tl.MarginLeft + (cW * 0.35F)},            New PageSplitArea(tl) With {.ColumnWidth = -cW * 0.3F}        }        '' Split options to control splitting text between pages:        Dim tso = New TextSplitOptions(tl) With {            .RestMarginTop = margin,            .MinLinesInFirstParagraph = 2,            .MinLinesInLastParagraph = 2        }        '' Generate a number of "chapters", provide outline entry for each:        Const NChapters = 20        doc.Pages.Add()        For i = 1 To NChapters            '' Print chapter header across all columns:            Dim chapter = $"Chapter {i}"            tlCaption.Clear()            tlCaption.Append(chapter)            tlCaption.PerformLayout(True)            doc.Pages.Last.Graphics.DrawTextLayout(tlCaption, PointF.Empty)            '' Add outline node for the chapter:            doc.Outlines.Add(New OutlineNode(chapter, New DestinationFitV(doc.Pages.Last, Nothing)))            ''            '' Clear last chapter's text and add new chapter:            tl.FirstLineIsStartOfParagraph = True            tl.LastLineIsEndOfParagraph = True            tl.Clear()            tl.Append(Util.LoremIpsum(5, 7, 9, 15, 25))            tl.PerformLayout(True)            '' Variable to hold last chapter end's bottom coord:            Dim contentBottom = 0F            '' Print the chapter:            Dim tls = New TextLayoutSplitter(tl)            While (True)                Dim tlCol0 = tls.SplitAndBalance(psas, tso)                Dim g = doc.Pages.Last.Graphics                g.DrawTextLayout(tlCol0, PointF.Empty)                g.DrawTextLayout(psas(0).TextLayout, PointF.Empty)                g.DrawTextLayout(psas(1).TextLayout, PointF.Empty)                If tls.SplitResult <> SplitResult.Split Then                    '' End of chapter, find out how much height left on page for next chapter:                    contentBottom = tl.ContentY + tl.ContentHeight                    contentBottom = Math.Max(contentBottom, psas(0).TextLayout.ContentRectangle.Bottom)                    contentBottom = Math.Max(contentBottom, psas(1).TextLayout.ContentRectangle.Bottom)                    '' Done printing chapter:                    Exit While                End If                '' Continue printing chapter on new page:                psas(0).MarginTop = margin                psas(1).MarginTop = margin                doc.Pages.Add()            End While            '' Next chapter - find out if we have enough space left on current page to start new chapter:            If contentBottom + captionH < pageHeight * 0.8F Then                '' Start new chapter on current page:                contentBottom += pageHeight * 0.05F                tlCaption.MarginTop = contentBottom                tl.MarginTop = contentBottom + captionH                psas(0).MarginTop = tl.MarginTop                psas(1).MarginTop = tl.MarginTop            ElseIf i < NChapters Then                '' Start new chapter on new page:                tlCaption.MarginTop = margin                tl.MarginTop = margin + captionH                psas(0).MarginTop = tl.MarginTop                psas(1).MarginTop = tl.MarginTop                doc.Pages.Add()            End If        Next        ''        '' Done:        doc.Save(stream)        Return doc.Pages.Count    End FunctionEnd Class