OptimizeBuffer(RasterCodecs,IntPtr,Int64,ImageOptimizerOptions,ImageOptimizerProgress) Method

'Declaration
 
Public Overloads Function OptimizeBuffer( _
   ByVal codecs As RasterCodecs, _
   ByVal buffer As IntPtr, _
   ByVal length As Long, _
   ByVal options As ImageOptimizerOptions, _
   ByVal progressCallback As ImageOptimizerProgress _
) As RasterNativeBuffer

Public Sub TestPngImageOptimizer()
   ' Initialize the RasterCodecs class
   Dim Codecs As RasterCodecs = New RasterCodecs()

   ' The input and output location
   Dim inputFileName As String = Path.Combine(LEAD_VARS.ImagesDir, "LittleGFlyingAlpha.png")
   Dim outputFolder As String = Path.Combine(LEAD_VARS.ImagesDir, "OptimizedImages")

   ' Initialize a new Optimizer object
   Dim optimizer As ImageOptimizer = New ImageOptimizer()

   ' Optimization Options
   Dim options As ImageOptimizerOptions = ImageOptimizerOptions.Default

   '' Set custom optimization options
   options.Distance = 20
   options.Percent = 15
   options.PngQualityFactor = 4

   Dim bufferPtr As IntPtr
   Dim bufferSize As Integer = 0
   LoadFileIntoPointer(inputFileName, bufferPtr, bufferSize)

   If (IntPtr.Zero <> bufferPtr AndAlso bufferSize > 0) Then
      Dim optBuffer As RasterNativeBuffer = optimizer.OptimizeBuffer(Codecs, bufferPtr, bufferSize, options, Nothing)

      ' Free orgBuffer.PointerBuffer, since it won't be needed anymore.
      Marshal.FreeHGlobal(bufferPtr)

      ' Save this image into the output folder
      ' Make sure the output folder exists
      If (Not Directory.Exists(outputFolder)) Then
         Directory.CreateDirectory(outputFolder)
      End If

      ' Get the name of the output file from the input file
      Dim outputFileName As String = Path.Combine(outputFolder, Path.GetFileName(inputFileName))

      ' Save the optimized buffer to the output file
      Using fs As FileStream = File.Create(outputFileName)

         Dim optArray(CInt(optBuffer.Length)) As Byte

         Marshal.Copy(optBuffer.Data, optArray, 0, optArray.Length)
         fs.Write(optArray, 0, optArray.Length)
      End Using

      ' Free optBuffer.PointerBuffer, since it won't be needed anymore.
      Marshal.FreeHGlobal(optBuffer.Data)

      ' Compare the original image size with the optimized size.
      Dim orgSize As Long = New FileInfo(inputFileName).Length
      Dim optSize As Long = New FileInfo(outputFileName).Length
      Dim percentage As Integer = CType(CType(optSize * 100.0 / orgSize, Double), Integer)

      Dim message As String = String.Format( _
         "Original image size: {0} KB{1}Optimized image size: {2} KB{1}Percentage: {3}%", _
         orgSize / 1024, Environment.NewLine, optSize / 1024, _
         100 - percentage)
      Console.WriteLine(message)
   End If

   'shutdown the RasterCodecs class.
End Sub

' This method opens an image file and loads it into IntPtr.
Private Sub LoadFileIntoPointer(ByVal fileName As String, ByRef ptr As IntPtr, ByRef size As Integer)
   Using fs As FileStream = File.OpenRead(fileName)
      ' Allocate memory to load the file
      size = CType(fs.Length, Integer)
      ptr = Marshal.AllocHGlobal(size)

      ' Load in 32K chunks
      Const bufferSize As Integer = 32 * 1024
      Dim buffer(bufferSize) As Byte

      Dim bytesToRead As Integer

      Dim bytesLeft As Integer = CType(fs.Length, Integer)
      Dim tempPtr As IntPtr = ptr   ' where we are
      Do
         ' read a chunk
         bytesToRead = Math.Min(bufferSize, bytesLeft)
         If (bytesToRead > 0) Then
            fs.Read(buffer, 0, bytesToRead)

            ' copy into our buffer
            Marshal.Copy(buffer, 0, tempPtr, bytesToRead)

            ' move the temp pointer
            tempPtr = New IntPtr(tempPtr.ToInt64() + bytesToRead)

            bytesLeft -= bytesToRead
         End If
      Loop While (bytesToRead > 0)
   End Using
End Sub

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