'''' This code is part of Document Solutions for PDF .NET demos.'' Copyright (c) MESCIUS inc. All rights reserved.''Imports SystemImports System.IOImports System.DrawingImports System.LinqImports System.Collections.GenericImports GrapeCity.Documents.PdfImports GrapeCity.Documents.TextImports GrapeCity.Documents.SvgImports GCTEXT = GrapeCity.Documents.Text
'' This sample is similar to SvgClipArt, but after loading each SVG image'' it converts all strokes and fills in it to grayscale.Public Class SvgToGrayscale    Sub ToGrayscale(ByVal elements As SvgElementCollection)        For Each el In elements            If TypeOf el Is SvgGraphicsElement Then                Dim elg = DirectCast(el, SvgGraphicsElement)                elg.Stroke = PaintToGrayscale(elg.Stroke)                elg.Fill = PaintToGrayscale(elg.Fill)            End If            ToGrayscale(el.Children)        Next    End Sub
    '' Simplified conversion of an SvgPaint to grayscale    '' (Y formula from https://goodcalculators.com/rgb-to-grayscale-conversion-calculator/):    Function PaintToGrayscale(ByVal src As SvgPaint) As SvgPaint        If src Is Nothing Then            Return Nothing        ElseIf src.PaintType = SvgPaintType.Color Then            Dim rgb = src.Color.Rgb            Dim Y = CInt(Math.Round(0.299 * rgb.R + 0.587 * rgb.G + 0.114 * rgb.B))            Return New SvgPaint(Color.FromArgb(Y, Y, Y))        Else            Return New SvgPaint(Color.Gray)        End If    End Function
    Function CreatePDF(ByVal stream As Stream) As Integer        '' Load images from the resources folder:        Dim images = New List(Of (String, GcSvgDocument))()        For Each fname In Directory.GetFiles(Path.Combine("Resources", "SvgClipArt"), "*", SearchOption.AllDirectories)            Dim svg = GcSvgDocument.FromFile(fname)            ToGrayscale(svg.RootSvg.Children)            images.Add((Path.GetFileName(fname), svg))        Next        images.Shuffle()
        Dim doc = New GcPdfDocument()        '' Font and format for captions:        Const sMargin As Single = 72.0F / 6        Dim font = GCTEXT.Font.FromFile(Path.Combine("Resources", "Fonts", "NotoSans-Regular.ttf"))        Dim tf = New TextFormat() With {.Font = font, .FontSize = sMargin * 0.65F}
        '' Set up a 3x4 layout grid with 1/2" margins all around:        Const margin As Single = 36        Const rows As Integer = 4        Const cols As Integer = 3        Dim gapx As Single = 72.0F / 4        Dim gapy As Single = gapx        Dim sWidth As Single = (doc.PageSize.Width - margin * 2 + gapx) / cols        Dim sHeight As Single = (doc.PageSize.Height - margin * 2 + gapy) / rows        If sWidth > sHeight Then            gapx += sWidth - sHeight            sWidth = sHeight        Else            gapy += sHeight - sWidth            sHeight = sWidth        End If        Dim ip = New PointF(margin, margin)
        '' Render all images within the grid, adding new pages as needed:        Dim g = doc.NewPage().Graphics        For i = 0 To images.Count - 1            '' Draw border around image:            Dim rect = New RectangleF(ip, New SizeF(sWidth - gapx, sHeight - gapy))            g.FillRectangle(rect, Color.LightGray)            g.DrawRectangle(rect, Color.Black, 0.5F)            rect.Inflate(-sMargin, -sMargin)
            '' Draw the SVG:            Dim svg = images(i).Item2            Dim s = svg.GetIntrinsicSize(SvgLengthUnits.Points)            If s.Width > 0 AndAlso s.Height > 0 Then                '' If image proportions are different from our target rectangle,                '' we resize the rectangle centering the image in it:                Dim qSrc = s.Width / s.Height                Dim qTgt = rect.Width / rect.Height                If qSrc < qTgt Then                    rect.Inflate(rect.Width * (qSrc / qTgt - 1) / 2, 0)                ElseIf qSrc > qTgt Then                    rect.Inflate(0, rect.Height * (qTgt / qSrc - 1) / 2)                End If            End If            '' Render the SVG:            g.DrawSvg(svg, rect)
            '' Print image file name as caption in the bottom slide margin:            g.DrawString(Path.GetFileName(images(i).Item1), tf,                New RectangleF(rect.X, rect.Bottom, rect.Width, sMargin),                TextAlignment.Center, ParagraphAlignment.Near, False)            ip.X += sWidth            If ip.X + sWidth > doc.PageSize.Width AndAlso i < images.Count - 1 Then                ip.X = margin                ip.Y += sHeight                If ip.Y + sHeight > doc.PageSize.Height Then                    g = doc.NewPage().Graphics                    ip.Y = margin                End If            End If        Next
        '' Done:        doc.Save(stream)        '' Dispose images after saving the PDF:        images.ForEach(Sub(t_) t_.Item2.Dispose())        Return doc.Pages.Count    End FunctionEnd Class