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LEADTOOLS Image Processing (Leadtools.ImageOptimization assembly)
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ImageOptimizer Class






Members 
Leadtools.ImageOptimization Namespace : ImageOptimizer Class
Provides methods to optimize one image or a directory of images in one of the supported formats.
Object Model
Syntax
public class ImageOptimizer 
'Declaration
 
Public Class ImageOptimizer 
'Usage
 
Dim instance As ImageOptimizer

            

        

            

            

            

        

            

            
public ref class ImageOptimizer 

            

        

            

        

            
            
            
            
Remarks
If the image is a 16-, 24-, or 32-bit 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 1-, 4-, or 8-bits per pixel, the Percent and Distance are used.


For more information, refer to Image Optimization Using The ImageOptimizer Class.


            
Example
This example will optimize a PNG image file and then save it to a separate folder

             
    

            
            

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Imports Leadtools
Imports Leadtools.Codecs
Imports Leadtools.ImageOptimization
Imports Leadtools.Support.Examples

<TestMethod()> _
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

            

   

     

            
using Leadtools;
using Leadtools.Codecs;
using Leadtools.ImageOptimization;

[TestMethod]
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

            
            
See Also
Reference
ImageOptimizer Members

Leadtools.ImageOptimization Namespace




        
    

	
    

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