GetPixelColor Method

Summary

Returns the color of the specified pixel.

Syntax

Objective-C

C++

Java

public RasterColor GetPixelColor( 
   int row, 
   int column 
)

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

- (LTRasterColor *)getPixelColorAtRow:(NSInteger)row  
                               column:(NSInteger)column

public RasterColor getPixelColor( 
  int row,  
  int 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 can represent an index into an 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.

In the Document and Medical toolkits, the COLORREF value can represent a 16 bit grayscale value if pBitmap is a 12 or 16-bit grayscale bitmap. To avoid confusion with an RGB value, set the COLORREF_GRAY16 mask (0x04000000). In this case (0x0400YYYY), the lower 16 bits (0xYYYY) of the COLORREF value represent the 16-bit grayscale value. (0x0400FFFF is 16-bit white and 0x04000000 is 16-bit black.) This is not a standard Windows value. Therefore, although LEADTOOLS functions will recognize a COLORREF having this format, but Windows functions will not.

This method supports signed/unsigned data images.

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

For more information refer to Accounting for View Perspective.

Example

This example uses GetPixelColor and SetPixelColor to invert the colors of the pixels in a line in the upper left part of the displayed image.

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 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:\LEADTOOLS21\Resources\Images"; 
}

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 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:\LEADTOOLS21\Resources\Images" 
End Class

Requirements

Target Platforms

Reference

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Help Version 21.0.2021.7.2

Leadtools Assembly

Introduction

Getting Started

Namespaces

Leadtools Namespace

Leadtools.ImageProcessing Namespace

Assemblies