LEADTOOLS Image Processing (Leadtools.ImageOptimization assembly)
LEAD Technologies, Inc

PngQualityFactor Property

Example 





Gets or sets the value that represents the quality factor to be used in the image optimization operation.
Syntax
public int PngQualityFactor {get; set;}
'Declaration
 
Public Property PngQualityFactor As Integer
'Usage
 
Dim instance As ImageOptimizerOptions
Dim value As Integer
 
instance.PngQualityFactor = value
 
value = instance.PngQualityFactor
public int PngQualityFactor {get; set;}
 get_PngQualityFactor();
set_PngQualityFactor(value);
public:
property int PngQualityFactor {
   int get();
   void set (    int value);
}

Property Value

The PngQualityFactor can be a value between 0 and 9 where: The Default value is 9.
Remarks
The PngQualityFactor is used only if the original image format is RasterImageFormat.Png. Bits per pixel: 1, 4, 8, 24, 32, 48, and 64.
Example
 
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
public void TestPngImageOptimizer( )
   {
      // Initialize the RasterCodecs class
      RasterCodecs codecs = new RasterCodecs();

      // The input and output location
      string inputFileName = Path.Combine(LEAD_VARS.ImagesDir, "LittleGFlyingAlpha.png");
      string outputFolder = Path.Combine(LEAD_VARS.ImagesDir, "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.
   }

   // 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);
      }
   }

static class LEAD_VARS
{
   public const string ImagesDir = @"C:\Users\Public\Documents\LEADTOOLS Images";
}
Requirements

Target Platforms: Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

See Also

Reference

ImageOptimizerOptions Structure
ImageOptimizerOptions Members