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Percent Property
See Also  Example
Leadtools.ImageOptimization Namespace > ImageOptimizerOptions Structure : Percent Property



Gets or sets the value that represents the percent redundancy to be used in the image optimization operation.

Syntax

Visual Basic (Declaration) 
Public Property Percent As Integer
Visual Basic (Usage)Copy Code
Dim instance As ImageOptimizerOptions
Dim value As Integer
 
instance.Percent = value
 
value = instance.Percent
C# 
public int Percent {get; set;}
C++/CLI 
public:
property int Percent {
   int get();
   void set (int value);
}

Return Value

The Percent value can be a value between 0 and 100. The default value is 10.

Example

Visual BasicCopy Code
Public Sub TestPngImageOptimizer()
   ' Initialize the RasterCodecs class
   RasterCodecs.Startup()
   Dim Codecs As RasterCodecs = New RasterCodecs()

   ' The input and output location
   Dim inputFileName As String = LeadtoolsExamples.Common.ImagesPath.Path + "Image1.png"
   Dim outputFolder As String = LeadtoolsExamples.Common.ImagesPath.Path + "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.
   RasterCodecs.Shutdown()
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
C#Copy Code
public void TestPngImageOptimizer( ) 
{ 
   // Initialize the RasterCodecs class 
   RasterCodecs.Startup(); 
   RasterCodecs codecs = new RasterCodecs(); 
 
   // The input and output location 
   string inputFileName = LeadtoolsExamples.Common.ImagesPath.Path + "Image1.png"; 
   string outputFolder = LeadtoolsExamples.Common.ImagesPath.Path + "OptimizedImages"; 
 
   // Initialize a new Optimizer object 
   ImageOptimizer optimizer = new ImageOptimizer(); 
 
   // Optimization Options 
   ImageOptimizerOptions options = ImageOptimizerOptions.Default; 
 
   // Set custom optimization options 
   options.Distance = 20; 
   options.Percent = 15; 
   options.PngQualityFactor = 4; 
 
   IntPtr bufferPtr; 
   int bufferSize = 0; 
   LoadFileIntoPointer(inputFileName, out bufferPtr, out bufferSize); 
 
   if(IntPtr.Zero != bufferPtr && bufferSize > 0) 
   { 
      RasterNativeBuffer optBuffer = optimizer.OptimizeBuffer(codecs, bufferPtr, bufferSize, options, null); 
 
      // 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(!Directory.Exists(outputFolder)) 
         Directory.CreateDirectory(outputFolder); 
 
      // Get the name of the output file from the input file 
      string outputFileName = Path.Combine(outputFolder, Path.GetFileName(inputFileName)); 
 
      // Save the optimized buffer to the output file 
      using(FileStream fs = File.Create(outputFileName)) 
      { 
         byte[] optArray = new byte[optBuffer.Length]; 
 
         Marshal.Copy(optBuffer.Data, optArray, 0, optArray.Length); 
         fs.Write(optArray, 0, optArray.Length); 
      } 
 
      // Free optBuffer.PointerBuffer, since it won't be needed anymore. 
      Marshal.FreeHGlobal(optBuffer.Data); 
 
      // Compare the original image size with the optimized size. 
      long orgSize = new FileInfo(inputFileName).Length; 
      long optSize = new FileInfo(outputFileName).Length; 
      int percentage = (int)((double)optSize * 100.0 / orgSize); 
 
      string message = string.Format( 
         "Original image size: {0} KB{1}Optimized image size: {2} KB{1}Percentage: {3}%", 
         orgSize / 1024, Environment.NewLine, optSize / 1024, 
         100 - percentage); 
      MessageBox.Show(message); 
   } 
 
   //shutdown the RasterCodecs class. 
   RasterCodecs.Shutdown(); 
} 
 
// This method opens an image file and loads it into IntPtr. 
private void LoadFileIntoPointer(string fileName, out IntPtr ptr, out int size) 
{ 
   using(FileStream fs = File.OpenRead(fileName)) 
   { 
      // Allocate memory to load the file 
      size = (int)fs.Length; 
      ptr = Marshal.AllocHGlobal(size); 
 
      // Load in 32K chunks 
      const int bufferSize = 32 * 1024; 
      byte[] buffer = new byte[bufferSize]; 
 
      int bytesToRead; 
      int bytesLeft = (int)fs.Length; 
      IntPtr tempPtr = ptr;   // where we are 
      do 
      { 
         // read a chunk 
         bytesToRead = Math.Min(bufferSize, bytesLeft); 
         if(bytesToRead > 0) 
         { 
            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; 
         } 
      } 
      while(bytesToRead > 0); 
   } 
}

Remarks

The Percent value will be used if the original image format is one the following:
  1. Png File:
  2. Gif File:
  3. Bmp File
If the image is a 16-, 24-, or 32-bit BMP image, the real number of colors used in the image is calculated and when possible the image is saved with lower bits per pixel. If the image is a 1-, 4-, or 8-bits per pixel BMP image, the Percent and Distance are used.

Requirements

Target Platforms: Microsoft .NET Framework 2.0, Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 family

See Also