'''' This code is part of Document Solutions for Imaging demos.'' Copyright (c) MESCIUS inc. All rights reserved.''Imports SystemImports System.IOImports System.DrawingImports System.Collections.GenericImports System.LinqImports System.NumericsImports GrapeCity.Documents.DrawingImports GrapeCity.Documents.TextImports GrapeCity.Documents.ImagingImports 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.'''' The SVG clip art used in this sample is from freesvg.org.Public Class SvgToGrayscale    Private Sub ToGrayscale(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/):    Private Function PaintToGrayscale(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 As Integer = 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
    '' Main entry point.    Public Function GenerateImage(pixelSize As Size, dpi As Single, opaque As Boolean, Optional sampleParams As String() = Nothing) As GcBitmap        Const rows As Integer = 4        Const cols As Integer = 4        Dim margin As Single = dpi / 2.0F        Dim sMargin As Single = margin / 4.0F
        '' Load images from the resources folder:        Dim fnames As New List(Of String)(Directory.GetFiles(Path.Combine("Resources", "SvgClipArt"), "*", SearchOption.AllDirectories))        fnames.Shuffle()
        Dim images As New List(Of Tuple(Of String, GcSvgDocument))()        For Each fname In fnames.Take(rows * cols)            Dim svg = GcSvgDocument.FromFile(fname)            ToGrayscale(svg.RootSvg.Children)            images.Add(Tuple.Create(Path.GetFileName(fname), svg))        Next
        '' Font and format for captions:        Dim font = GCTEXT.Font.FromFile(Path.Combine("Resources", "Fonts", "FreeSans.ttf"))        Dim tf = New TextFormat() With {.Font = font, .FontSize = sMargin * 0.65F}
        '' Set up a 4x4 layout grid:        Dim gapx As Single = margin / 4.0F, gapy As Single = gapx        Dim sWidth As Single = (pixelSize.Width - margin * 2 + gapx) / cols        Dim sHeight As Single = (pixelSize.Height - margin * 2 + gapy) / rows        If sWidth > sHeight Then            gapx += sWidth - sHeight            sWidth = sHeight        Else            gapy += sHeight - sWidth            sHeight = sWidth        End If        Dim ip As New PointF(margin, margin)
        '' Resulting bitmap:        Dim bmp = New GcBitmap(pixelSize.Width, pixelSize.Height, opaque, dpi, dpi)
        '' Render all images within the grid:        Using g = bmp.CreateGraphics(Color.White)            For i As Integer = 0 To images.Count() - 1                '' Draw border around image:                Dim rect As 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) / 2.0F, 0)                    ElseIf qSrc > qTgt Then                        rect.Inflate(0, rect.Height * (qTgt / qSrc - 1) / 2.0F)                    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 > pixelSize.Width) AndAlso (i < images.Count() - 1) Then                    ip.X = margin                    ip.Y += sHeight                End If            Next        End Using
        '' Dispose images after saving the result:        images.ForEach(Sub(t_) t_.Item2.Dispose())
        '' Done:        Return bmp    End FunctionEnd Class