Pocowrite

MainWindow.xaml

<Window x:Class="MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="Pocowrite" Height="176" Width="435">
    <Grid Background="#40444b">
        <InkCanvas Margin="12,12,12,38" Name="InkCanvas1" Background="#36393f" MinHeight="1" MinWidth="1" />
        <Button Content="Copy" HorizontalAlignment="Left" Margin="12,0,0,12" Name="CopyBtn" Width="75" Height="23" VerticalAlignment="Bottom" />
        <Button Content="Clear" HorizontalAlignment="Right" Margin="0,0,12,12" Name="ClearBtn" Width="75" Background="#FFDDDDDD" Height="23" VerticalAlignment="Bottom" />
    </Grid>
</Window>

MainWindow.xaml.vb

Imports System.IO
Imports System.Drawing

Class MainWindow

    Private Function SignatureToBitmapBytes() As Byte()
        'https://www.centrolutions.com/blog/post/2008/12/09/Convert-WPF-InkCanvas-to-Bitmap.aspx
        'Dim margin As Integer = CInt(InkCanvas1.Margin.Left)
        'Dim width As Integer = CInt(InkCanvas1.ActualWidth) - margin
        'Dim height As Integer = CInt(InkCanvas1.ActualHeight) - margin
        'Dim rtb As RenderTargetBitmap = New RenderTargetBitmap(width, height, 96.0R, 96.0R, PixelFormats.[Default])
        'rtb.Render(InkCanvas1)

        Dim rtb As New RenderTargetBitmap(InkCanvas1.ActualWidth, InkCanvas1.ActualHeight, 96.0R, 96.0R, PixelFormats.[Default])
        'Dim bvm As New BitmapVisualManager(rtb)
        Dim dvInk As New DrawingVisual
        Dim dcInk As DrawingContext = dvInk.RenderOpen()
        Dim bgpen As New Windows.Media.Pen
        bgpen.Brush = New Windows.Media.SolidColorBrush(Windows.Media.Color.FromRgb(54, 57, 63))
        dcInk.DrawRectangle(New Windows.Media.SolidColorBrush(Windows.Media.Color.FromRgb(54, 57, 63)), bgpen, New Rect(0D, 0D,
        InkCanvas1.ActualWidth, InkCanvas1.ActualHeight))
        For Each stroke In InkCanvas1.Strokes
            stroke.Draw(dcInk)
        Next
        dcInk.Close()
        rtb.Render(dvInk)


        ' https://microsoft.public.windows.developer.winfx.avalon.narkive.com/vwqGNgNA/how-get-image-from-inkcanvas
        Dim encoder As BmpBitmapEncoder = New BmpBitmapEncoder()
        encoder.Frames.Add(BitmapFrame.Create(rtb))
        Dim bitmapBytes As Byte()

        Using ms As MemoryStream = New MemoryStream()
            encoder.Save(ms)
            ms.Position = 0
            bitmapBytes = ms.ToArray()
        End Using

        Return bitmapBytes
    End Function

    Private Sub CopyBtn_Click(sender As System.Object, e As System.Windows.RoutedEventArgs) Handles CopyBtn.Click
        My.Computer.Clipboard.SetImage(New Bitmap(New MemoryStream(SignatureToBitmapBytes)))
    End Sub

    Private Sub Window_Loaded(sender As System.Object, e As System.Windows.RoutedEventArgs) Handles MyBase.Loaded
        InkCanvas1.DefaultDrawingAttributes.Color = Colors.White
    End Sub

    Private Sub ClearBtn_Click(sender As System.Object, e As System.Windows.RoutedEventArgs) Handles ClearBtn.Click
        InkCanvas1.Strokes.Clear()
    End Sub
End Class