'''' This code is part of Document Solutions for Imaging demos.'' Copyright (c) MESCIUS inc. All rights reserved.''Imports System.IOImports System.DrawingImports GrapeCity.Documents.DrawingImports GrapeCity.Documents.TextImports GrapeCity.Documents.ImagingImports GCTEXT = GrapeCity.Documents.TextImports GCDRAW = GrapeCity.Documents.Drawing
'' This sample demonstrates how to use different grayscale effects.'' See also MatrixEffects1 and MatrixEffects2.Public Class ThresholdingEffects    Function GenerateImage(        ByVal pixelSize As Size,        ByVal dpi As Single,        ByVal opaque As Boolean,        Optional ByVal sampleParams As String() = Nothing) As GcBitmap
        opaque = False        Dim bmp = New GcBitmap(pixelSize.Width, pixelSize.Height, opaque, dpi, dpi)        Using origBmp = New GcBitmap()            '' Load a sample photo:            Dim imagePath = Path.Combine("Resources", "Stock", "bw-hiking.jpg")            Using stm = New FileStream(imagePath, FileMode.Open, FileAccess.Read, FileShare.Read, 4096, FileOptions.RandomAccess)                origBmp.Load(stm)            End Using
            origBmp.SetAlphaTo255()            origBmp.Opaque = False
            '' Resize the original photo so we can place 4 samples of it            '' on the resulting bitmap:            Dim w = pixelSize.Width / 2            Dim h = pixelSize.Height / 2            Using sizedBmp = origBmp.Resize(w, h, InterpolationMode.Cubic)                '' Copy the resized original into 4 quadrants of the resulting bitmap:                bmp.BitBlt(sizedBmp, 0, 0)                bmp.BitBlt(sizedBmp, w, 0)                bmp.BitBlt(sizedBmp, 0, h)                bmp.BitBlt(sizedBmp, w, h)            End Using
            Dim lineh = 2
            '' Keep the pixels in top left quadrant intact,            '' apply effects to the other 3 quadrants            '' (these effects make sense for grayscale images only, so we do it before adding captions):            bmp.ApplyEffect(OtsuThresholdingEffect.Get(), New Rectangle(w + lineh, 0, w - lineh, h - lineh))            bmp.ApplyEffect(BradleyThresholdingEffect.Get(), New Rectangle(0, h + lineh, w - lineh, h - lineh))            bmp.ApplyEffect(BradleyThresholdingEffect.Get(16, 6), New Rectangle(w + lineh, h + lineh, w - lineh, h - lineh))
            '' Add borders between the quadrants, And captions for each            Using g = bmp.CreateGraphics(Nothing)                Dim foreColor = Color.Yellow                Dim backColor = Color.Blue                Dim fnt = GCTEXT.Font.FromFile(Path.Combine("Resources", "Fonts", "FreeMono.ttf"))                g.DrawLine(w, 0, w, h * 2, New GCDRAW.Pen(foreColor, lineh * 2))                g.DrawLine(0, h, w * 2, h, New GCDRAW.Pen(foreColor, lineh * 2))                Dim tf = New TextFormat() With {.Font = fnt, .FontSize = 18, .ForeColor = foreColor, .BackColor = backColor, .FontBold = True}                g.DrawString(" Original image ", tf, New PointF(0, 0))                g.DrawString(" OtsuThresholdingEffect ", tf, New PointF(w + lineh, 0))                g.DrawString(" BradleyThresholdingEffect ", tf, New PointF(0, h + lineh))                g.DrawString(" BradleyThresholdingEffect(16,6) ", tf, New PointF(w + lineh, h + lineh))            End Using        End Using        '' Done        Return bmp    End FunctionEnd Class