StartDithering Method

Initializes the buffered dithering of an image.

Syntax

C#
Visual Basic
WinRT C#
Java
Objective-C
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:(nullable NSArray<LTRasterColor *> *)palette 
                colors:(NSUInteger)colors 
                 error:(NSError **)error

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 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

This example dithers each line in one image and writes it to another image.

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.Controls
Imports Leadtools.Dicom
Imports Leadtools.Drawing
Imports Leadtools.Svg

      
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.Dicom;
using Leadtools.Drawing;
using Leadtools.Controls;
using Leadtools.Svg;

      
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