GetPixelColor Method

Returns the color of the specified pixel.

Syntax

Visual Basic
C#
WinRT C#
WinRT JavaScript
C++

public RasterColor GetPixelColor( 
   int row,
   int column
)

'Declaration
 
Public Function GetPixelColor( _
   ByVal row As Integer, _
   ByVal column As Integer _
) As RasterColor

'Usage
 
Dim instance As RasterImage
Dim row As Integer
Dim column As Integer
Dim value As RasterColor
 
value = instance.GetPixelColor(row, column)

public RasterColor GetPixelColor( 
   int row,
   int column
)

 function Leadtools.RasterImage.GetPixelColor( 
   row ,
   column 
)

public:
RasterColor GetPixelColor( 
   int row,
   int column
)

Parameters

row: The zero-based row number of the pixel.
column: The zero-based column number of the pixel.

Return Value

This method returns a RasterColor value which may represent an index into a image palette, a grayscale value (Medical Imaging only), or red, green, and blue color values.

Remarks

The standard Windows values for RasterColor represent either red, green, and blue color values, or an index into the image palette. A RasterColor value with the RGB value of 0x00BBGGRR represents the blue, green, and red color values for the specified pixel, where 0xBB is the blue value, 0xGG is the green value and 0xRR is the red value. If 0x01000000 is set in the RGB value of RasterColor (0x010000ZZ), the lower 8 bits (0xZZ) represent an index into the image palette which holds the color value.

You can use the SetPixelColor method to assign the returned value to another pixel.

This method uses image coordinates to specify the pixel. Therefore, you must account for the view perspective of the image.

If you specify a pixel that is outside the image or outside the region (if the image has one), this method throws an exception.

This method does not support alpha values for 32 and 64-bit color images and the alpha value of the returned color should not be used. Instead, use the GetPixel and SetPixel methods.

This method does not support signed images.

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

For more information refer to Accounting for View Perspective.

Example

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

Public Sub GetPixelColorExample()
      Dim codecs As RasterCodecs = New RasterCodecs()
      ' Load the image
      Dim image As RasterImage = codecs.Load(Path.Combine(LEAD_VARS.ImagesDir, "IMAGE1.CMP"))

      ' Specify a line of pixels.
      Dim Offset As LeadPoint = New LeadPoint(image.Width \ 8, image.Height \ 8)
      Dim XSize As Integer = image.Width \ 3

      ' Invert the colors of pixels in the line.
      Dim i As Integer = 0
      Do While i < XSize
         Dim OldOffset As LeadPoint = New LeadPoint(Offset.X, Offset.Y)
         ' Adjust the XOffset and YOffset  in case the view perspective is not TopLeft.
         Offset = image.PointToImage(RasterViewPerspective.TopLeft, Offset)
         Dim PixelColor As RasterColor = image.GetPixelColor(Offset.Y, Offset.X)
         PixelColor.R = CByte(255 - PixelColor.R)
         PixelColor.G = CByte(255 - PixelColor.G)
         PixelColor.B = CByte(255 - PixelColor.B)
         image.SetPixelColor(Offset.Y, Offset.X, PixelColor)

         Offset = OldOffset ' Restore Offset
         Offset.X = Offset.X + 1
         i += 1
      Loop

      codecs.Save(image, Path.Combine(LEAD_VARS.ImagesDir, "IMAGE1_GetPixelColor.BMP"), RasterImageFormat.Bmp, 0)

      image.Dispose()
      codecs.Dispose()
   End Sub

Public NotInheritable Class LEAD_VARS
   Public Const ImagesDir As String = "C:\Users\Public\Documents\LEADTOOLS Images"
End Class

public void GetPixelColorExample()
   {
      RasterCodecs codecs = new RasterCodecs();
      // Load the image
      RasterImage image = codecs.Load(Path.Combine(LEAD_VARS.ImagesDir, "IMAGE1.CMP"));

      // Specify a line of pixels.
      LeadPoint offset = new LeadPoint(image.Width / 8, image.Height / 8);
      int XSize = image.Width / 3;

      // Invert the colors of pixels in the line.
      for(int i = 0; i < XSize; i++)
      {
         LeadPoint oldOffset = new LeadPoint(offset.X, offset.Y);
         // Adjust the XOffset and YOffset  in case the view perspective is not TopLeft.
         offset = image.PointToImage(Leadtools.RasterViewPerspective.TopLeft, offset);
         RasterColor pixelColor = image.GetPixelColor(offset.Y, offset.X);
         pixelColor.R = (byte)(255 - pixelColor.R);
         pixelColor.G = (byte)(255 - pixelColor.G);
         pixelColor.B = (byte)(255 - pixelColor.B);
         image.SetPixelColor(offset.Y, offset.X, pixelColor);

         offset = oldOffset; // Restore Offset
         offset.X = offset.X + 1;
      }

      codecs.Save(image, Path.Combine(LEAD_VARS.ImagesDir, "IMAGE1_GetPixelColor.BMP"), RasterImageFormat.Bmp, 0);

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

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

RasterImageExamples.prototype.GetPixelColorExample = function ( )
{
   Tools.SetLicense ( ) ;

   with (Leadtools) {
      with (Leadtools.Codecs) {

         var codecs = new RasterCodecs();

         // Load the image

         var srcFileName = "Assets\\Image1.cmp";
         var image;
         return Tools.AppInstallFolder().getFileAsync(srcFileName).then(function (loadFile) {
            return codecs.loadAsync(LeadStreamFactory.create(loadFile))
         })
            .then(function (img) {
               image = img;

               // Specify a line of pixels.
               var offset = LeadPointHelper.create(image.width / 8, image.height / 8);
               var XSize = image.width / 3;

               // Invert the colors of pixels in the line.
               for (var i = 0; i < XSize; i++) {
                  var oldOffset = LeadPointHelper.create(offset.X, offset.Y);
                  // Adjust the XOffset and YOffset  in case the view perspective is not TopLeft.
                  offset = image.pointToImage(Leadtools.RasterViewPerspective.topLeft, offset);
                  var pixelColor = image.getPixelColor(offset.y, offset.x);
                  pixelColor.r = Math.max ( 255, Math.min ( 0, (255 - pixelColor.r) ) );
                  pixelColor.g = Math.max ( 255, Math.min ( 0, (255 - pixelColor.g) ) ) ;
                  pixelColor.b = Math.max ( 255, Math.min ( 0, (255 - pixelColor.b) ) );
                  image.setPixelColor(offset.y, offset.x, pixelColor);

                  offset = oldOffset; // Restore Offset
                  offset.x = offset.x + 1;
               }

               return Tools.AppLocalFolder().createFileAsync("IMAGE1_GetPixelColor.BMP")
            })
            .then(function (saveFile) {
               var saveStream = LeadStreamFactory.create(saveFile);
               codecs.saveAsync(image, saveStream, RasterImageFormat.bmp, 24)
            })
            .then(function () {
               image.close();
               codecs.close();
            });
      }
   }
}

[TestMethod]
public async Task GetPixelColorExample()
{
   RasterCodecs codecs = new RasterCodecs();
   // Load the image
   string srcFileName = @"Assets\Image1.cmp";
   StorageFile loadFile = await Tools.AppInstallFolder.GetFileAsync(srcFileName);
   RasterImage image = await codecs.LoadAsync(LeadStreamFactory.Create(loadFile));
   // Specify a line of pixels.
   LeadPoint offset = LeadPointHelper.Create(image.Width / 8, image.Height / 8);
   int XSize = image.Width / 3;

   // Invert the colors of pixels in the line.
   for (int i = 0; i < XSize; i++)
   {
      LeadPoint oldOffset = LeadPointHelper.Create(offset.X, offset.Y);
      // Adjust the XOffset and YOffset  in case the view perspective is not TopLeft.
      offset = image.PointToImage(Leadtools.RasterViewPerspective.TopLeft, offset);
      RasterColor pixelColor = image.GetPixelColor(offset.Y, offset.X);
      pixelColor.R = (byte)(255 - pixelColor.R);
      pixelColor.G = (byte)(255 - pixelColor.G);
      pixelColor.B = (byte)(255 - pixelColor.B);
      image.SetPixelColor(offset.Y, offset.X, pixelColor);

      offset = oldOffset; // Restore Offset
      offset.X = offset.X + 1;
   }

   StorageFile saveFile = await Tools.AppLocalFolder.CreateFileAsync("IMAGE1_GetPixelColor.BMP");
   ILeadStream saveStream = LeadStreamFactory.Create(saveFile);
   await codecs.SaveAsync(image, saveStream, RasterImageFormat.Bmp, 24);

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

public void GetPixelColorExample(RasterImage image, Stream destStream)
{
   // Specify a line of pixels.
   LeadPoint Offset = new LeadPoint(image.Width / 8, image.Height / 8);
   int XSize = image.Width / 3;
   // Invert the colors of pixels in the line.
   for (int i = 0; i < XSize; i++)
   {
      LeadPoint OldOffset = new LeadPoint(Offset.X, Offset.Y);
      // Adjust the XOffset and YOffset  in case the view perspective is not TopLeft.
      Offset = image.PointToImage(Leadtools.RasterViewPerspective.TopLeft, Offset);
      RasterColor PixelColor = image.GetPixelColor(Offset.Y, Offset.X);
      PixelColor.R = (byte)(255 - PixelColor.R);
      PixelColor.G = (byte)(255 - PixelColor.G);
      PixelColor.B = (byte)(255 - PixelColor.B);
      image.SetPixelColor(Offset.Y, Offset.X, PixelColor);

      Offset = OldOffset; // Restore Offset
      Offset.X = Offset.X + 1;
   }

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

   image.Dispose();
}

Public Sub GetPixelColorExample(ByVal image As RasterImage, ByVal destStream As Stream)
   ' Specify a line of pixels.
   Dim Offset As LeadPoint = New LeadPoint(image.Width / 8, image.Height / 8)
   Dim XSize As Integer = image.Width / 3
   ' Invert the colors of pixels in the line.
   Dim i As Integer = 0
   Do While i < XSize
      Dim OldOffset As LeadPoint = New LeadPoint(Offset.X, Offset.Y)
      ' Adjust the XOffset and YOffset  in case the view perspective is not TopLeft.
      Offset = image.PointToImage(RasterViewPerspective.TopLeft, Offset)
      Dim PixelColor As RasterColor = image.GetPixelColor(Offset.Y, Offset.X)
      PixelColor.R = CByte(255 - PixelColor.R)
      PixelColor.G = CByte(255 - PixelColor.G)
      PixelColor.B = CByte(255 - PixelColor.B)
      image.SetPixelColor(Offset.Y, Offset.X, PixelColor)

      Offset = OldOffset ' Restore Offset
      Offset.X = Offset.X + 1
      i += 1
   Loop

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

   image.Dispose()
End Sub

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

Reference

RasterImage Class
RasterImage Members
GetPixel Method
SetPixel Method