'''' This code is part of Document Solutions for Imaging demos.'' Copyright (c) MESCIUS inc. All rights reserved.''Imports System.DrawingImports System.IOImports System.LinqImports System.NumericsImports GrapeCity.Documents.DrawingImports GrapeCity.Documents.TextImports GrapeCity.Documents.Imaging.SkiaImports GCTEXT = GrapeCity.Documents.TextImports GCDRAW = GrapeCity.Documents.Drawing
'' Text is always rendered with anti-aliasing in Skia.'' Graphics rendering on the other hand can be controlled by'' setting the GcSkiaGraphics.Aliased property.'' This example shows the difference between shapes drawn'' with that property set to false (which is the default)'' and true. Note the more jagged appearance of some lines'' in the lower part of the image (drawn with Aliased set'' to false).Public Class SkiaAntialiasing    Public Shared ReadOnly Property IsSkiaOnly As Boolean = True
    Private _font As GCTEXT.Font = Nothing
    '' Helper method to draw a polygon and a caption beneath it.    '' Can also be used to just calculate the points without actual drawing.    '' startAngle is for the first point, clockwise from (1,0).    Private Function DrawPolygon(g As GcGraphics, center As PointF, r As Single, n As Integer, startAngle As Single, pen As GCDRAW.Pen, Optional caption As String = Nothing) As PointF()        Dim pts As PointF() = New PointF(n - 1) {}        For i = 0 To n - 1            pts(i) = New PointF(center.X + CSng(r * Math.Cos(startAngle + 2 * Math.PI * i / n)), center.Y + CSng(r * Math.Sin(startAngle + 2 * Math.PI * i / n)))        Next        If pen IsNot Nothing Then            g.DrawPolygon(pts, pen)        End If        If Not String.IsNullOrEmpty(caption) Then            DrawCaption(g, center, r, caption)        End If        Return pts    End Function
    '' Helper method to draw a caption beneath a shape:    Private Sub DrawCaption(g As GcGraphics, center As PointF, r As Single, caption As String)        g.DrawString(caption,            New TextFormat() With                {                    .Font = _font,                    .FontSize = 12                },            New RectangleF(center.X - r, center.Y - r, r * 2, r * 2),            TextAlignment.Center, ParagraphAlignment.Center, False)    End Sub
    '' Main entry point.    Public Function GenerateImageStream(targetMime As String, pixelSize As Size, dpi As Single, opaque As Boolean, Optional sampleParams As String() = Nothing) As Stream        Select Case targetMime            Case Util.MimeTypes.JPEG, Util.MimeTypes.PNG, Util.MimeTypes.WEBP                '' OK            Case Else                Throw New Exception("This sample uses Skia to create the image, and only supports JPEG, PNG and WEBP output formats.")        End Select
        _font = GCTEXT.Font.FromFile(Path.Combine("Resources", "Fonts", "FreeSerif.ttf"))        Dim Inch = dpi        Dim bmp = New GcSkiaBitmap(pixelSize.Width, pixelSize.Height, opaque)        Using g = bmp.CreateGraphics(Color.White)            DrawShapes(g, bmp.PixelWidth, bmp.PixelHeight, False)            DrawShapes(g, bmp.PixelWidth, bmp.PixelHeight, True)        End Using
        '' Done:        Dim ms = New MemoryStream()        Select Case targetMime            Case Util.MimeTypes.JPEG                bmp.SaveAsJpeg(ms)            Case Util.MimeTypes.PNG                bmp.SaveAsPng(ms)            Case Util.MimeTypes.WEBP                bmp.SaveAsWebp(ms)            Case Else                System.Diagnostics.Debug.Assert(False)        End Select        Return ms    End Function
    Private Sub DrawShapes(g As GcGraphics, pixelWidth As Integer, pixelHeight As Integer, aliased As Boolean)        Dim gskia = TryCast(g, GcSkiaGraphics)        If gskia IsNot Nothing Then            gskia.Aliased = aliased        End If
        '' Set up the helper layout grid:        Dim Inch = g.Resolution        Dim grid = New With            {                .Cols = 4,                .Rows = 3,                .MarginX = Inch / 6,                .MarginY = Inch / 4,                .Radius = Inch * 0.6F,                .StepX = (pixelWidth - Inch / 2) / 4,                .StepY = (pixelHeight - Inch / 4) / 7F            }
        '' Insertion point of the next figure's center:        Dim startIp As PointF = New PointF(grid.MarginX + grid.StepX / 2, grid.MarginY + grid.StepY / 2 + 10)        If aliased Then            startIp.Y += pixelHeight \ 2        End If
        Dim ip As PointF = startIp
        '' Header:        Dim pad = 8        Dim bord = New RectangleF(pad, pad + If(aliased, pixelHeight \ 2, 0), pixelWidth - pad * 2, pixelHeight \ 2 - pad * 2)        g.DrawString($"Shapes (Skia) - Aliased is {aliased}",            New TextFormat() With                {                    .Font = _font,                    .FontSize = 14                },            bord,            TextAlignment.Center, ParagraphAlignment.Near)        g.DrawRoundRect(bord, pad, Color.MediumPurple, 2, DashStyle.DashDot)
        '' Pen used to draw shapes:        Dim pen = New GCDRAW.Pen(Color.Orange, 1)        pen.LineJoin = PenLineJoin.Round        Dim fill = 100 '' Surfaces fill alpha
        '' Circle:        g.DrawEllipse(New RectangleF(ip.X - grid.Radius, ip.Y - grid.Radius, grid.Radius * 2, grid.Radius * 2), pen)        DrawCaption(g, ip, grid.Radius, "Circle")        ip.X += grid.StepX
        '' Ellipse:        g.DrawEllipse(New RectangleF(ip.X - grid.Radius * 1.4F, ip.Y - grid.Radius / 2, grid.Radius * 2 * 1.4F, grid.Radius), pen)        DrawCaption(g, ip, grid.Radius, "Ellipse")        ip.X += grid.StepX
        '' Cylinder:        Dim radX As Single = grid.Radius / 1.4F        Dim radY As Single = grid.Radius / 6        Dim height As Single = grid.Radius * 1.8F        g.DrawEllipse(New RectangleF(ip.X - radX, ip.Y - height / 2, radX * 2, radY * 2), pen)        g.FillEllipse(New RectangleF(ip.X - radX, ip.Y + height / 2 - radY * 2, radX * 2, radY * 2), Color.FromArgb(fill, pen.Color))        g.DrawEllipse(New RectangleF(ip.X - radX, ip.Y + height / 2 - radY * 2, radX * 2, radY * 2), pen)        g.DrawLine(New PointF(ip.X - radX, ip.Y - height / 2 + radY), New PointF(ip.X - radX, ip.Y + height / 2 - radY), pen)        g.DrawLine(New PointF(ip.X + radX, ip.Y - height / 2 + radY), New PointF(ip.X + radX, ip.Y + height / 2 - radY), pen)        DrawCaption(g, ip, grid.Radius, "Cylinder")        pen.Color = Color.Indigo        ip.X += grid.StepX
        '' Cube:        Dim cubex As Single = 6        Dim cubePtsFar = DrawPolygon(g, New PointF(ip.X - cubex, ip.Y - cubex), grid.Radius, 4, CSng(-Math.PI) / 4, pen)        Dim cubePtsNear = DrawPolygon(g, New PointF(ip.X + cubex, ip.Y + cubex), grid.Radius, 4, CSng(-Math.PI) / 4, pen)        g.DrawLine(cubePtsFar(0), cubePtsNear(0), pen)        g.DrawLine(cubePtsFar(1), cubePtsNear(1), pen)        g.DrawLine(cubePtsFar(2), cubePtsNear(2), pen)        g.DrawLine(cubePtsFar(3), cubePtsNear(3), pen)        g.FillPolygon(New PointF() {cubePtsFar(1), cubePtsFar(2), cubePtsNear(2), cubePtsNear(1)}, Color.FromArgb(fill, pen.Color))        DrawCaption(g, ip, grid.Radius, "Cube")        pen.Color = Color.DarkGreen        ip.X = startIp.X        ip.Y += grid.StepY
        '' Pentagon:        DrawPolygon(g, ip, grid.Radius, 5, CSng(-Math.PI) / 2, pen, "Pentagon")        ip.X += grid.StepX
        '' Hexagon:        '' For sample sake, we apply a transform to make the hexagon wider and shorter:        g.Transform = Matrix3x2.CreateScale(1.4F, 0.8F) * Matrix3x2.CreateTranslation(ip.X, ip.Y)        DrawPolygon(g, PointF.Empty, grid.Radius, 6, 0, pen, Nothing)        g.Transform = Matrix3x2.Identity        DrawCaption(g, ip, grid.Radius, "Hexagon")        ip.X += grid.StepX
        '' Octagon:        DrawPolygon(g, ip, grid.Radius, 8, CSng(-Math.PI) / 8, pen, "Octagon")        pen.Color = Color.DarkRed        ip.X += grid.StepX
        '' Triangle:        DrawPolygon(g, ip, grid.Radius, 3, CSng(-Math.PI) / 2, pen, "Triangle")        ip.X = startIp.X        ip.Y += grid.StepY
        '' Filled pentagram:        Dim pts = DrawPolygon(g, ip, grid.Radius, 5, CSng(-Math.PI) / 2, pen, "Pentagram")        pts = New PointF() {pts(0), pts(2), pts(4), pts(1), pts(3)}        g.FillPolygon(pts, Color.FromArgb(fill, pen.Color))        g.DrawPolygon(pts, pen)        ip.X += grid.StepX
        '' Set up a simple kind of oblique projection to draw a pyramid:        Dim angle = Math.PI / 6        Dim s As Single = CSng(Math.Sin(angle))        Dim c As Single = CSng(Math.Cos(angle))        Dim project As Func(Of Single, Single, Single, PointF) = Function(x_, y_, z_) New PointF(x_ - c * y_ * 0.5F, -(z_ - s * y_ * 0.5F))        Dim p3d As Func(Of Vector3, PointF) = Function(v_) project(v_.X, v_.Y, v_.Z)        Dim hedge As Single = grid.Radius '' 1/2 edge        '' Debug - draw the 3 axis:        '' g.DrawLine(project(0, 0, 0), project(100, 0, 0), Color.Red);        '' g.DrawLine(project(0, 0, 0), project(0, 100, 0), Color.Green);        '' g.DrawLine(project(0, 0, 0), project(0, 0, 100), Color.Blue);        '' 3d points forming a square pyramid:        Dim pts3d = New Vector3() {            New Vector3(-hedge, -hedge, 0),            New Vector3(hedge, -hedge, 0),            New Vector3(hedge, hedge, 0),            New Vector3(-hedge, hedge, 0),            New Vector3(0, 0, hedge * 2)        }        '' project the points to draw the pyramid:        pts = pts3d.Select(Function(v_) p3d(v_)).ToArray()        g.Transform = Matrix3x2.CreateTranslation(ip.X, ip.Y + hedge * 0.7F)        '' Visible edges:        g.DrawPolygon(New PointF() {pts(4), pts(1), pts(2), pts(3), pts(4), pts(2)}, pen)        '' Invisible edges:        pen.Width /= 2        pen.Color = Color.FromArgb(fill, pen.Color)        g.DrawLine(pts(0), pts(4), pen)        g.DrawLine(pts(0), pts(1), pen)        g.DrawLine(pts(0), pts(3), pen)        g.FillPolygon(pts.Take(4).ToArray(), pen.Color)        ''        g.Transform = Matrix3x2.Identity        DrawCaption(g, ip, grid.Radius, "Pyramid")        ip.X += grid.StepX        pen.Width *= 2        pen.Color = Color.Green
        '' Cone:        Dim baseh As Single = grid.Radius * 0.3F        pts = DrawPolygon(g, ip, grid.Radius, 3, CSng(-Math.PI) / 2, Nothing, "Cone")        g.DrawLines(New PointF() {pts(2), pts(0), pts(1)}, pen)        Dim rect = New RectangleF(pts(2).X, pts(2).Y - baseh / 2, pts(1).X - pts(2).X, baseh)        g.FillEllipse(rect, Color.FromArgb(fill, pen.Color))        g.DrawEllipse(rect, pen)        ip.X += grid.StepX
        '' Trapezoid (use DrawPolygon to just get the points of the square):        Dim dx As Single = 10        pts = DrawPolygon(g, ip, grid.Radius, 4, CSng(-Math.PI) / 4, Nothing, "Trapezoid")        pts(0).X -= dx        pts(1).X += dx        pts(2).X -= dx        pts(3).X += dx        g.DrawPolygon(pts, pen)    End SubEnd Class