StartDithering Method

Initializes the buffered dithering of an image.

Syntax

C#
Visual Basic
WinRT C#
Objective-C
Java
WinRT JavaScript
C++

public void StartDithering( 
   RasterColor[] palette,
   int colors
)

'Declaration
 
Public Sub StartDithering( _
   ByVal palette() As RasterColor, _
   ByVal colors As Integer _
)

'Usage
 
Dim instance As RasterImage
Dim palette() As RasterColor
Dim colors As Integer
 
instance.StartDithering(palette, colors)

public void StartDithering( 
   RasterColor[] palette,
   int colors
)

-(BOOL)startDithering:(NSArray*)palette 
               colors:(unsigned int)colors 
                error:(NSError**)outError;

public void startDithering(
  RasterColor[] palette, 
  int colors
)

 function Leadtools.RasterImage.StartDithering( 
   palette ,
   colors 
)

public:
void StartDithering( 
   array<RasterColor>^ palette,
   int colors
)

Parameters

palette: The palette this uses for dithering. You can specify your own palette, or use a null reference (Nothing in Visual Basic) for LEAD's fixed palette.
colors: Number of colors used in the palette. If the palette contains more colors, only the first colors colors are used. Valid values are 2 to 256.

Remarks

The following flow chart shows how the methods relate to each other:

Dithering Flow Chart

The following properties from the RasterImage are used to control the dithering operation:

Width
Height
BitsPerPixel
Order - if BitsPerPixel is greater than 8
DitheringMethod - if BitsPerPixel is less than 16

This method does not support signed images.

For more information, refer to Introduction to Image Processing With LEADTOOLS.

Example

C#
Visual Basic
WinRT C#
WinRT JavaScript
Silverlight C#
Silverlight VB

Copy Code

Imports Leadtools
Imports Leadtools.Codecs
Imports Leadtools.ImageProcessing
Imports Leadtools.ImageProcessing.Core
Imports Leadtools.ImageProcessing.Color
Imports Leadtools.WinForms
Imports Leadtools.Dicom
Imports Leadtools.Drawing

Public Sub StartDitheringExample()
   Dim codecs As RasterCodecs = New RasterCodecs()
   ' Load an image that has BottomLeft ViewPerspective
   Dim image As RasterImage = codecs.Load(Path.Combine(LEAD_VARS.ImagesDir, "IMAGE1.CMP"))

   Dim Palette As RasterColor() = RasterPalette.Fixed(8)

   ' Create the new palletized image.
   Dim destinationImage As RasterImage = New RasterImage(RasterMemoryFlags.Conventional, image.Width, image.Height, 8, image.Order, image.ViewPerspective, Palette, IntPtr.Zero, 0)

   ' Set the dithering method.
   image.DitheringMethod = RasterDitheringMethod.StevensonArce

   ' Initialize the dithering process.
   image.StartDithering(Palette, 256)

   ' Allocate the output buffer for 8-bit data.
   Dim InBuffer As Byte() = New Byte(image.Width * 3 - 1) {} ' Buffer to hold the input row.
   Dim OutBuffer As Byte() = New Byte(image.Width - 1) {} ' Buffer to hold the output row.

   ' Use DitherLine method to process each row in the image.
   Dim i As Integer = 0
   Do While i < image.Height
      image.GetRow(i, InBuffer, 0, image.BytesPerLine)
      image.DitherLine(InBuffer, 0, OutBuffer, 0)
      destinationImage.SetRow(i, OutBuffer, 0, destinationImage.BytesPerLine)
      i += 1
   Loop
   ' End the dithering process.
   image.StopDithering()

   codecs.Save(destinationImage, Path.Combine(LEAD_VARS.ImagesDir, "IMAGE1_DitherLine.BMP"), RasterImageFormat.Bmp, 0)

   image.Dispose()
   destinationImage.Dispose()
   codecs.Dispose()
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.ImageProcessing;
using Leadtools.ImageProcessing.Core;
using Leadtools.ImageProcessing.Color;
using Leadtools.WinForms;
using Leadtools.Dicom;
using Leadtools.Drawing;

      
public void StartDitheringExample()
{
   RasterCodecs codecs = new RasterCodecs();
   // Load an image that has BottomLeft ViewPerspective
   RasterImage image = codecs.Load(Path.Combine(ImagesPath.Path, "IMAGE1.CMP"));
   RasterColor[] Palette = RasterPalette.Fixed(256);

   // Create the new palletized image.
   RasterImage destinationImage = new RasterImage(RasterMemoryFlags.Conventional, image.Width, image.Height, 8, image.Order, image.ViewPerspective, Palette, IntPtr.Zero, 0);

   // Set the dithering method.
   image.DitheringMethod = RasterDitheringMethod.StevensonArce;

   // Initialize the dithering process.
   image.StartDithering(Palette, 256);

   // Allocate the output buffer for 8-bit data.
   byte[] InBuffer = new byte[image.Width * 3];// Buffer to hold the input row.
   byte[] OutBuffer = new byte[image.Width];// Buffer to hold the output row.

   // Use DitherLine method to process each row in the image.
   for(int i = 0; i < image.Height; i++)
   {
      image.GetRow(i, InBuffer, 0, image.BytesPerLine);
      image.DitherLine(InBuffer, 0, OutBuffer, 0);
      destinationImage.SetRow(i, OutBuffer, 0, destinationImage.BytesPerLine);
   }
   // End the dithering process.
   image.StopDithering();

   codecs.Save(destinationImage, Path.Combine(ImagesPath.Path, "IMAGE1_DitherLine.BMP"), RasterImageFormat.Bmp, 0);

   image.Dispose();
   destinationImage.Dispose();
   codecs.Dispose();
}

RasterImageExamples.prototype.StartDitheringExample = function () {
   Tools.SetLicense();
   with (Leadtools) {
      with (Leadtools.Codecs) {
         var codecs = new RasterCodecs();

         // Load an image that has BottomLeft ViewPerspective
         var srcFileName = "Assets\\Image1.cmp";
         var image;
         var destinationImage;
         return Tools.AppInstallFolder().getFileAsync(srcFileName).then(function (loadFile) {
            return codecs.loadAsync(LeadStreamFactory.create(loadFile))
         })
            .then(function (img) {
               image = img;

               var Palette = [RasterColorHelper.create(0, 0, 0),
                  RasterColorHelper.create(255, 255, 255),
                  RasterColorHelper.create(255, 0, 0),
                  RasterColorHelper.create(0, 255, 0),
                  RasterColorHelper.create(0, 0, 255),
                  RasterColorHelper.create(255, 255, 0),
                  RasterColorHelper.create(0, 255, 255),
                  RasterColorHelper.create(255, 0, 255),
                  RasterColorHelper.create(128, 128, 0),
                  RasterColorHelper.create(0, 128, 128),
                  RasterColorHelper.create(128, 128, 128),
                  RasterColorHelper.create(128, 0, 128),
                  RasterColorHelper.create(128, 255, 128),
                  RasterColorHelper.create(128, 255, 255),
                  RasterColorHelper.create(255, 128, 128),
                  RasterColorHelper.create(255, 255, 128)
               ];

               // Create the new palletized image.
               destinationImage = new RasterImage(RasterMemoryFlags.conventional, image.width, image.height, 4, image.order, image.viewPerspective, Palette);

               // Set the dithering method.
               image.ditheringMethod = RasterDitheringMethod.stevensonArce;

               // Initialize the dithering process.
               image.startDithering(Palette, Palette.length);

               // Allocate the output buffer for 8-bit data.
               var InBuffer = new Uint8Array(image.bytesPerLine);// Buffer to hold the input row.
               var OutBuffer = new Uint8Array(destinationImage.bytesPerLine);// Buffer to hold the output row.

               // Use DitherLine method to process each row in the image.
               image.accessData();
               for (var i = 0; i < image.height; i++) {
                  image.getRow(i, InBuffer, 0, image.bytesPerLine);
                  image.ditherLine(InBuffer, OutBuffer);
                  destinationImage.setRow(i, OutBuffer, 0, destinationImage.bytesPerLine);
               }
               // End the dithering process.
               image.stopDithering();
               image.releaseData();

               return Tools.AppLocalFolder().createFileAsync("IMAGE1_DitherLine.BMP")
            })
            .then(function (saveFile) {
               var saveStream = LeadStreamFactory.create(saveFile);
               return codecs.saveAsync(destinationImage, saveStream, RasterImageFormat.bmp, 0)
            })
            .then(function () {

               image.Dispose();
               destinationImage.Dispose();
               codecs.Dispose();
            });
      }
   }
}

using Leadtools;
using Leadtools.Codecs;
using Leadtools.ImageProcessing;
using Leadtools.ImageProcessing.Core;
using Leadtools.ImageProcessing.Color;
using Leadtools.Dicom;

      
public async Task StartDitheringExample()
{
   RasterCodecs codecs = new RasterCodecs();
   // Load an image that has BottomLeft ViewPerspective
   string srcFileName = @"Assets\Image1.cmp";
   StorageFile loadFile = await Tools.AppInstallFolder.GetFileAsync(srcFileName);
   RasterImage image = await codecs.LoadAsync(LeadStreamFactory.Create(loadFile));
   RasterColor[] Palette = { RasterColorHelper.Create(0,0,0),
                             RasterColorHelper.Create(255,255,255),
                             RasterColorHelper.Create(255,0,0),
                             RasterColorHelper.Create(0,255,0),
                             RasterColorHelper.Create(0,0,255),
                             RasterColorHelper.Create(255,255,0),
                             RasterColorHelper.Create(0,255,255),
                             RasterColorHelper.Create(255,0,255),
                             RasterColorHelper.Create(128,128,0),
                             RasterColorHelper.Create(0,128,128),
                             RasterColorHelper.Create(128,128,128),
                             RasterColorHelper.Create(128,0,128),
                             RasterColorHelper.Create(128,255,128),
                             RasterColorHelper.Create(128,255,255),
                             RasterColorHelper.Create(255,128,128),
                             RasterColorHelper.Create(255,255,128),
                           };

   // Create the new palletized image.
   RasterImage destinationImage = new RasterImage(RasterMemoryFlags.Conventional, image.Width, image.Height, 4, image.Order, image.ViewPerspective, Palette);

   // Set the dithering method.
   image.DitheringMethod = RasterDitheringMethod.StevensonArce;

   // Initialize the dithering process.
   image.StartDithering(Palette, Palette.Length);

   // Allocate the output buffer for 8-bit data.
   byte[] InBuffer = new byte[image.BytesPerLine];// Buffer to hold the input row.
   byte[] OutBuffer = new byte[destinationImage.BytesPerLine];// Buffer to hold the output row.

   // Use DitherLine method to process each row in the image.
   image.AccessData();
   for (int i = 0; i < image.Height; i++)
   {
      image.GetRow(i, InBuffer, 0, image.BytesPerLine);
      image.DitherLine(InBuffer, 0, OutBuffer, 0);
      destinationImage.SetRow(i, OutBuffer, 0, destinationImage.BytesPerLine);
   }
   // End the dithering process.
   image.StopDithering();
   image.ReleaseData();

   StorageFile saveFile = await Tools.AppLocalFolder.CreateFileAsync("IMAGE1_DitherLine.BMP");
   ILeadStream saveStream = LeadStreamFactory.Create(saveFile);
   await codecs.SaveAsync(destinationImage, saveStream, RasterImageFormat.Bmp, 0);

   image.Dispose();
   destinationImage.Dispose();
   codecs.Dispose();
}

using Leadtools;
using Leadtools.Codecs;
using Leadtools.Dicom;
using Leadtools.ImageProcessing;
using Leadtools.ImageProcessing.Core;
using Leadtools.ImageProcessing.Color;
using Leadtools.Examples;
using Leadtools.Windows.Media;

public void StartDitheringExample(RasterImage image, Stream destStream)
{
   RasterColor[] Palette = RasterPalette.Fixed(256);
   // Create the new palletized image.
   RasterImage destinationImage = new RasterImage(RasterMemoryFlags.Conventional, image.Width, image.Height, 8, image.Order, image.ViewPerspective, Palette, null, 0);

   // Set the dithering method.
   image.DitheringMethod = RasterDitheringMethod.StevensonArce;

   // Initialize the dithering process.
   image.StartDithering(Palette, 256);

   // Allocate the output buffer for 8-bit data.
   byte[] InBuffer = new byte[image.Width * 3];// Buffer to hold the input row.
   byte[] OutBuffer = new byte[image.Width];// Buffer to hold the output row.

   // Use DitherLine method to process each row in the image.
   for (int i = 0; i < image.Height; i++)
   {
      image.GetRow(i, InBuffer, 0, image.BytesPerLine);
      image.DitherLine(InBuffer, 0, OutBuffer, 0);
      destinationImage.SetRow(i, OutBuffer, 0, destinationImage.BytesPerLine);
   }
   // End the dithering process.
   image.StopDithering();

   RasterCodecs codecs = new RasterCodecs();
   codecs.Save(destinationImage, destStream, RasterImageFormat.Bmp, 0);

   image.Dispose();
   destinationImage.Dispose();
}

Imports Leadtools
Imports Leadtools.Codecs
Imports Leadtools.Dicom
Imports Leadtools.ImageProcessing
Imports Leadtools.ImageProcessing.Core
Imports Leadtools.ImageProcessing.Color
Imports Leadtools.Windows.Media

Public Sub StartDitheringExample(ByVal image As RasterImage, ByVal destStream As Stream)
   Dim Palette As RasterColor() = RasterPalette.Fixed(256)
   ' Create the new palletized image.
   Dim destinationImage As RasterImage = New RasterImage(RasterMemoryFlags.Conventional, image.Width, image.Height, 8, image.Order, image.ViewPerspective, Palette, Nothing, 0)

   ' Set the dithering method.
   image.DitheringMethod = RasterDitheringMethod.StevensonArce

   ' Initialize the dithering process.
   image.StartDithering(Palette, 256)

   ' Allocate the output buffer for 8-bit data.
   Dim InBuffer As Byte() = New Byte(image.Width * 3 - 1){} ' Buffer to hold the input row.
   Dim OutBuffer As Byte() = New Byte(image.Width - 1){} ' Buffer to hold the output row.

   ' Use DitherLine method to process each row in the image.
   Dim i As Integer = 0
   Do While i < image.Height
      image.GetRow(i, InBuffer, 0, image.BytesPerLine)
      image.DitherLine(InBuffer, 0, OutBuffer, 0)
      destinationImage.SetRow(i, OutBuffer, 0, destinationImage.BytesPerLine)
      i += 1
   Loop
   ' End the dithering process.
   image.StopDithering()

   Dim codecs As RasterCodecs = New RasterCodecs()
   codecs.Save(destinationImage, destStream, RasterImageFormat.Bmp, 0)

   image.Dispose()
   destinationImage.Dispose()
End Sub

Requirements

Target Platforms

Reference

RasterImage Class
RasterImage Members
Introduction to Image Processing With LEADTOOLS
Dithering Methods
Codecs.CodecsThumbnailOptions.DitheringMethod property
ImageProcessing.ColorResolutionCommand.DitheringMethod property
RasterDitheringMethod enumeration
RasterDefaults.DitheringMethod property
RasterImage.DitheringMethod property
RasterImage.DitherLine method
RasterImage.StopDithering method
RasterBufferConverter.Convert