'''' 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 GCTEXT = GrapeCity.Documents.TextImports GCDRAW = GrapeCity.Documents.Drawing
'' This example shows how to create a semi-transparent blurred shadow'' of a text and graphics image, offset by a specified amount.'' To achieve this the code employs the ApplyGaussianBlur and ToShadowBitmap'' methods of the GrayscaleBitmap class.Public Class Shadow    Private _font As GCTEXT.Font = GCTEXT.Font.FromFile(Path.Combine("Resources", "Fonts", "FreeSans.ttf"))
    Public Function GenerateImage(            ByVal pixelSize As Size,            ByVal dpi As Single,            ByVal opaque As Boolean,            Optional ByVal sampleParams As String() = Nothing) As GcBitmap
        '' Create a transparent bitmap and draw the shadow image on it (offset left/down by 30/50):        Dim bmp = New GcBitmap(pixelSize.Width, pixelSize.Height, False)        Using g = bmp.CreateGraphics(Color.Transparent)            Draw(g, 30, 50)        End Using
        '' Extract the alpha channel from GcBitmap to a GrayscaleBitmap:        Using gs = bmp.ToGrayscaleBitmap(ColorChannel.Alpha)
            '' Blur the GrayscaleBitmap to create a believable looking shadow:            gs.ApplyGaussianBlur(9)
            '' Convert the transparency mask from GrayscaleBitmap to GcBitmap,            '' filling the opaque pixels with the shadow color (CadetBlue),            '' also making the resulting 'shadow' slightly transparent (0.6f):            gs.ToShadowBitmap(bmp, Color.CadetBlue, 0.6F)        End Using
        '' Replace the transparent background with an opaque background color:        bmp.ConvertToOpaque(Color.LightGoldenrodYellow)
        '' Finally draw the original image without offset on top:        Using g = bmp.CreateGraphics()            Draw(g, 0, 0)        End Using
        '' Done        Return bmp    End Function
    Private Sub Draw(ByVal g As GcGraphics, ByVal offsetX As Single, ByVal offsetY As Single)        Dim baseT = Matrix3x2.CreateTranslation(offsetX, offsetY)        g.Transform = baseT        g.DrawEllipse(New RectangleF(100, 100, 300, 200), New GCDRAW.Pen(Color.Orange, 20))        g.DrawLine(New PointF(50, 400), New PointF(500, 50), New GCDRAW.Pen(Color.RoyalBlue, 20) With {            .LineCap = PenLineCap.Round        })        g.DrawString("Howl's Moving Castle",            New TextFormat With {                .Font = _font,                .FontSize = 40,                .ForeColor = Color.MistyRose,                .StrokePen = New GCDRAW.Pen(Color.DarkRed, 1)            },            New PointF(200, 150))        g.Transform =            Matrix3x2.CreateRotation(CSng(Math.PI / 6)) *            (Matrix3x2.CreateTranslation(50, 250) * baseT)        g.DrawString("The quick brown fox jumps over the lazy dog.",            New TextFormat With {                .Font = _font,                .FontSize = 18,                .ForeColor = Color.CornflowerBlue            },            New PointF(0, 0))        g.DrawRectangle(New RectangleF(-15, -10, 470, 50), New GCDRAW.Pen(Color.Salmon, 1))
        g.Transform = baseT
        '' Draw a window with four colored semi-transparent panes:        Dim wnd = New RectangleF(520, 420, 400, 500)        Dim winHalf = New SizeF(wnd.Width / 2, wnd.Height / 2)        Dim frame = Color.Brown        Dim glassTL = Color.FromArgb(&H70FF4600)        Dim glassTR = Color.FromArgb(&H70A5FF00)        Dim glassBL = Color.FromArgb(&H70007BFF)        Dim glassBR = Color.FromArgb(&H70FFCD00)
        g.FillRectangle(New RectangleF(wnd.Location, winHalf), glassTL)        g.FillRectangle(New RectangleF(New PointF(wnd.X + wnd.Width / 2, wnd.Y), winHalf), glassTR)        g.FillRectangle(New RectangleF(New PointF(wnd.X, wnd.Y + wnd.Height / 2), winHalf), glassBL)        g.FillRectangle(New RectangleF(New PointF(wnd.X + wnd.Width / 2, wnd.Y + wnd.Height / 2), winHalf), glassBR)
        g.DrawRectangle(wnd, New GCDRAW.Pen(frame, 30))        g.DrawLine(wnd.Left, wnd.Top + wnd.Height / 2, wnd.Right, wnd.Top + wnd.Height / 2, frame, 20)        g.DrawLine(wnd.Left + wnd.Width / 2, wnd.Top, wnd.Left + wnd.Width / 2, wnd.Bottom, frame, 20)
        g.Transform = Matrix3x2.Identity    End SubEnd Class