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



Gets or sets a value that represents the quality factor to be used when optimizing an image.

Syntax

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

Return Value

The JpegQualityFactor is a number used to balance between loss and quality during compression. You can set a value from 2 to 255, where 2 represents the highest quality and 255 represents the most compression. The default value is 35.

Example

Visual BasicCopy Code
Public Sub TestJpegImageOptimizer()
   ' 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 + "Slave.jpg"
   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.JpegQualityFactor = 255
   options.JpegColorSpace = ImageOptimizerJpegColorSpace.JpegColorSpace422

   ' Load the input file into a memory byte array
   Dim orgBuffer() As Byte = File.ReadAllBytes(inputFileName)

   ' Optimize this buffer
   Dim optBuffer() As Byte = optimizer.OptimizeBuffer(codecs, orgBuffer, 0, 0, options, AddressOf OptimizeBufferProgress)

   ' 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)
      fs.Write(optBuffer, 0, optBuffer.Length)
   End Using

   ' 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)
   MessageBox.Show(message)

   'shutdown the RasterCodecs class.
   RasterCodecs.Shutdown()
End Sub

Public Shared Function OptimizeBufferProgress(ByVal percent As Integer) As Boolean
   Console.WriteLine(String.Format("{0}%", percent))
   Return True
End Function
C#Copy Code
public void TestJpegImageOptimizer( ) 
{ 
   // Initialize the RasterCodecs class 
   RasterCodecs.Startup(); 
   RasterCodecs codecs = new RasterCodecs(); 
 
   // The input and output location 
   string inputFileName = LeadtoolsExamples.Common.ImagesPath.Path + "Slave.jpg"; 
   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.JpegQualityFactor = 255; 
   options.JpegColorSpace = ImageOptimizerJpegColorSpace.JpegColorSpace422; 
 
   // Load the input file into a memory byte array 
   byte[] orgBuffer = File.ReadAllBytes(inputFileName); 
 
   // Optimize this buffer 
   byte[] optBuffer = optimizer.OptimizeBuffer(codecs, orgBuffer, 0, orgBuffer.Length, options, OptimizeBufferProgress); 
 
   // 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)) 
      fs.Write(optBuffer, 0, optBuffer.Length); 
 
   // 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(); 
} 
 
static bool OptimizeBufferProgress(int percent) 
{ 
   Console.WriteLine(string.Format("{0}%", percent)); 
   return true; 
}

Remarks

The JpegQualityFactor is used only if the original image format is one of the following Jpeg formats:

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