GetRowColumnCompressed(WriteOnlyArray<Byte>,WriteOnlyArray<UInt16>,Int32,Int32,Int32,Int32) Method

'Declaration
 
Public Overloads Function GetRowColumnCompressed( _
   ByVal workBuffer As WriteOnlyArray(Of Byte), _
   ByVal runBuffer As WriteOnlyArray(Of UShort), _
   ByVal runBufferOffset As Integer, _
   ByVal row As Integer, _
   ByVal column As Integer, _
   ByVal width As Integer _
) As Integer

Public Sub GetRowColumnCompressedExample()
      Dim codecs As RasterCodecs = New RasterCodecs()
      ' Load the bitmap, at 1 bit per pixel, compressed
      codecs.Options.Load.Compressed = True
      Dim image As RasterImage = codecs.Load(Path.Combine(LEAD_VARS.ImagesDir, "OCR1.TIF"), 1, CodecsLoadByteOrder.Bgr, 1, 1)

      Dim xOffset As Integer ' Column offset of the rectangle to process.
      Dim xSize As Integer ' Pixel width of the rectangle to process.
      Dim yOffset As Integer ' Row offset of the rectangle to process.
      Dim ySize As Integer ' Pixel height of the rectangle to process.
      Dim i, n As Integer ' Counters.

      Dim buffer As Byte() ' Buffer to hold the expanded row.
      Dim runBuffer As System.UInt16() ' Buffer to hold the compressed row.
      Dim workBuffer As Byte() ' Work buffer.

      ' This example does not work with rotated view perspectives.
      If (image.ViewPerspective <> RasterViewPerspective.TopLeft) OrElse (image.ViewPerspective <> RasterViewPerspective.BottomLeft) Then
         image.ChangeViewPerspective(RasterViewPerspective.TopLeft)
      End If

      ' Specify a rectangle in the middle right part of the displayed image.
      xOffset = image.Width \ 3
      xSize = image.Width - xOffset
      yOffset = image.Height \ 3
      ySize = image.Height \ 3
      ' Adjust the YOffset if the view perspective is bottom left.
      If image.ViewPerspective = RasterViewPerspective.BottomLeft Then
         yOffset = image.Height - yOffset - ySize
      End If

      If image.IsGlobalMemory Then
         image.Access()
      End If
      ' Allocate the buffers.
      buffer = New Byte((xSize + 7) \ 8 - 1) {}
      runBuffer = New System.UInt16((xSize + 3) * 2 - 1) {}
      workBuffer = New Byte(image.BytesPerLine - 1) {}
      ' Invert the colors of pixels in the left half of the rectangle.
      ' Notice that we get the whole rectangle, but process only half of it.
      i = yOffset
      Do While i < (yOffset + ySize)
         image.GetRowColumnCompressed(workBuffer, runBuffer, 0, i, xOffset, xSize)
         RasterRleCompressor.ExpandRow(runBuffer, buffer, 0, 0, xSize)
         n = 0
         Do While n < (xSize / 16)
            buffer(n) = buffer(n) Xor Convert.ToByte(&HFF)
            n += 1
         Loop
         RasterRleCompressor.CompressRow(runBuffer, buffer, 0, 0, xSize)
         image.SetRowColumnCompressed(workBuffer, runBuffer, 0, i, xOffset, xSize)

         i += 1
      Loop
      If image.IsGlobalMemory Then
         image.Release()
      End If

      codecs.Save(image, Path.Combine(LEAD_VARS.ImagesDir, "IMAGE1_getrowcolcompresed.BMP"), RasterImageFormat.Bmp, 0)

      image.Dispose()
      codecs.Dispose()
   End Sub

Public NotInheritable Class LEAD_VARS
   Public Const ImagesDir As String = "C:\Users\Public\Documents\LEADTOOLS Images"
End Class