'''' This code is part of Document Solutions for PDF .NET demos.'' Copyright (c) MESCIUS inc. All rights reserved.''Imports System.IOImports System.DrawingImports System.LinqImports GrapeCity.Documents.PdfImports GrapeCity.Documents.TextImports GrapeCity.Documents.DrawingImports GCTEXT = GrapeCity.Documents.TextImports GCDRAW = GrapeCity.Documents.Drawing
Public Class AllBlendModes    Public Function CreatePDF(ByVal stream As Stream) As Integer        Dim doc = New GcPdfDocument()        Dim page = doc.NewPage()        Dim g = page.Graphics
        Dim iorchid = GCDRAW.Image.FromFile(Path.Combine("Resources", "ImagesBis", "orchid.jpg"))        Dim ispectr = GCDRAW.Image.FromFile(Path.Combine("Resources", "ImagesBis", "spectrum-pastel-500x500.png"))
        Const margin As Integer = 36        Const NCOLS As Integer = 4        Dim w = CInt((page.Size.Width - margin * 2) / NCOLS)        Dim h = (iorchid.Height * w) \ iorchid.Width
        ' Text layout for captions:        Dim tl = g.CreateTextLayout()        tl.DefaultFormat.Font = GCTEXT.Font.FromFile(Path.Combine("Resources", "Fonts", "NotoSansMono-Regular.ttf"))        tl.DefaultFormat.FontSize = 12        tl.ParagraphAlignment = ParagraphAlignment.Center        tl.TextAlignment = TextAlignment.Center        tl.MaxWidth = w        tl.MaxHeight = h        tl.MarginTop = h - g.MeasureString("QWERTY", tl.DefaultFormat).Height * 1.4F
        Dim row As Integer = 0        Dim col As Integer = 0        Dim dy As Integer = 0        Dim x As Integer = 0        Dim y As Integer = 0        Dim r As RectangleF = Nothing        Dim rc As RectangleF = Nothing        Dim blendMode As BlendMode = BlendMode.Normal        Dim iback As GCDRAW.Image = Nothing        Dim ifore As GCDRAW.Image = Nothing
        ' Render all blending modes in a grid:        Dim modes = System.Enum.GetValues(GetType(BlendMode))        For i As Integer = 0 To 1            row = 0            col = 0            If i = 0 Then                iback = ispectr                ifore = iorchid                Dim trc1 = Util.AddNote(                    "Below are tiles drawn by composing two images (a spectrum and an orchid) using the " &                    "different blend modes supported by DsPdf. " &                    "First the spectrum image is drawn normally, then it is overlaid by the orchid image " &                    "drawn in a supported blend mode. The blend mode name is shown below each tile." &                    vbLf &                    "Tiles on the second page are composed of the same images but drawn in reverse order: " &                    "the orchid is drawn normally, the spectrum is blended with it using the different modes." &                    vbLf &                    "Note that the current blend mode affects not only images but any drawing on a GcGraphics. " &                    "The blend mode names on the 2nd page illustrate this.",                    page)                dy = CInt(Fix(trc1.Bottom))            Else                iback = iorchid                ifore = ispectr                page = doc.Pages.Add()                g = page.Graphics                dy = 0            End If            For Each mode In modes                blendMode = CType(mode, BlendMode)                If Not g.IsBlendModeSupported(blendMode) Then                    Continue For                End If
                x = margin + w * col                y = margin + h * row + dy                r = New RectangleF(x, y, w, h)
                g.BlendMode = BlendMode.Normal                g.DrawImage(iback, r, Nothing, ImageAlign.StretchImage)                g.BlendMode = blendMode                g.DrawImage(ifore, r, Nothing, ImageAlign.StretchImage)                g.BlendMode = BlendMode.Normal
                ' Caption:                tl.Clear()                tl.Append(blendMode.ToString())                tl.PerformLayout(True)                rc = tl.ContentRectangle                rc.Offset(x, y)                rc.Inflate(4, 2)                g.FillRectangle(rc, Color.White)                g.DrawTextLayout(tl, New PointF(x, y))                col += 1                If col = NCOLS Then                    col = 0                    row += 1                End If            Next        Next        ' Text blends:        page = doc.Pages(1)        g = page.Graphics        Dim trc = Util.AddNote(            "Below are supported blend mode names rendered into rectangles using the corresponding blend mode. " &            "Each rectangle is first filled by the spectrum image using BlendMode.Normal, " &            "then black and white texts are drawn using the current blend mode, " &            "finally the same spectrum image is drawn using BlendMode.Difference to black out the background. " &            "Names prefixed with 'B:' are drawn in black, " &            "while names prefixed with 'W:' are drawn in white. " &            "Most combinations yield rather colorful results, but for some the results are invisible.",            page,            New RectangleF(margin, margin + h * row + 12, page.Bounds.Width - margin * 2, 0))
        Dim yoff = CInt(Fix(trc.Bottom)) + 12        tl.DefaultFormat.FontBold = True        tl.DefaultFormat.FontSize = 16        h = CInt(Fix(g.MeasureString("QWERTY", tl.DefaultFormat).Height * 1.4F)) * 2        tl.MaxWidth = w        tl.MaxHeight = h        tl.MarginTop = (h - h / 1.4F) / 2
        tl.DefaultFormat.ForeColor = Color.Black        Dim tfWhite = New TextFormat(tl.DefaultFormat) With {.ForeColor = Color.White}
        row = 0        col = 0        For Each mode In modes            blendMode = CType(mode, BlendMode)            If Not g.IsBlendModeSupported(blendMode) Then                Continue For            End If
            x = margin + w * col            y = yoff + h * row            r = New RectangleF(x, y, w, h)
            ' Draw spectrum image normally:            g.BlendMode = BlendMode.Normal            g.DrawImage(ispectr, r, Nothing, ImageAlign.StretchImage)            ' Draw blend mode name using the current blend mode:            tl.Clear()            tl.AppendLine($"B: {blendMode}")            tl.Append($"W: {blendMode}", tfWhite)            tl.PerformLayout(True)            rc = tl.ContentRectangle            rc.Offset(x, y)            rc.Inflate(4, 2)            ' Current blend mode:            g.BlendMode = blendMode            g.DrawTextLayout(tl, New PointF(x, y))            ' Draw spectrum image again using BlendMode.Difference            ' to produce (mostly) colorful text on black background:            g.BlendMode = BlendMode.Difference            g.DrawImage(ispectr, r, Nothing, ImageAlign.StretchImage)            ' Draw a rectangle to mark the current area:            g.BlendMode = BlendMode.Normal            g.DrawRectangle(r, Color.Gray)            col += 1            If col = NCOLS Then                col = 0                row += 1            End If        Next        ' Done:        doc.Save(stream)        Return doc.Pages.Count    End FunctionEnd Class