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AddColorRgbRangeToRegion Method

Creates or updates the image region by adding a region that consists of all the pixels that fall in the given RGB color range.
Public Sub AddColorRgbRangeToRegion( _ 
   ByVal lowerColor As RasterColor, _ 
   ByVal upperColor As RasterColor, _ 
   ByVal combineMode As RasterRegionCombineMode _ 
- (BOOL)addColorRgbRangeToRegion:(LTRasterColor *)lowerColor  
                      upperColor:(LTRasterColor *)upperColor  
                           error:(NSError **)error 
public void addColorRgbRangeToRegion( 
  RasterColor lowerColor,  
  RasterColor upperColor,  
  RasterRegionCombineMode combineMode 


Specifies the minimum (inclusive) R, G and B values. A pixel must have R,G, and B all greater than or equal to lowerColor and less than or equal to upperColor to be included in the region.

Specifies the maximum (inclusive) R, G and B values. A pixel must have R,G, and B all greater than or equal to lowerColor and less than or equal to upperColor to be included in the region.

The action to take regarding the existing image region, if one is defined.


This method uses the RGB color model to set a region based on a color range.

To be added to the region a color must fall in the range lowerColor.. upperColor. To set a region for all pure red, specify lowerColor and upperColor as follows:

lowerColor RGB(1,0,0) upperColor RGB(255,0,0)

Note that this would fail to include many colors that look red to the eye (like RGB(255,4,4)).

This method supports 12 and 16-bit grayscale and 48 and 64-bit color images. Support for 12 and 16-bit grayscale and 48 and 64-bit color images is available only in the Document/Medical Imaging editions.

This method supports signed/unsigned data images.

The AddColorRgbRangeToRegion function can use the Extended Grayscale mask. For more information, refer to Grayscale Images.

To update an existing region, you specify how the new region is to be combined with the existing one using the combineMode parameter. For more information, refer to RasterRegionCombineMode.

For more information, refer to Creating a Region.

For more information, refer to Saving A Region.

For more information, refer to Working with the Existing Region.

In the Document and Medical toolkits, the COLORREF value can represent a 16 bit grayscale value if RasterImage 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 methods will recognize a COLORREF having this format, but Windows methods will not.


This example will load an image, add a region corresponding to all colors that have an RGB that includes green but no red and no blue, and run the InvertCommand to show the affected area before saving the image back to disk.

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 AddColorRgbRangeToRegionExample() 
	RasterCodecs codecs = new RasterCodecs(); 
	string srcFileName = Path.Combine(LEAD_VARS.ImagesDir, "Image1.cmp"); 
	string destFileName = Path.Combine(LEAD_VARS.ImagesDir, "Image1_AddColorRgbRangeToRegion.bmp"); 
	// Load the image 
	RasterImage image = codecs.Load(srcFileName); 
	// Add the region 
	RasterColor lowerColor = new RasterColor(0, 1, 0); 
	RasterColor upperColor = new RasterColor(0, 255, 0); 
	image.AddColorRgbRangeToRegion(lowerColor, upperColor, RasterRegionCombineMode.Set); 
	// Draw something on the image 
	InvertCommand command = new InvertCommand(); 
	// Save the image 
	codecs.Save(image, destFileName, RasterImageFormat.Bmp, 24); 
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 AddColorRgbRangeToRegionExample() 
   Dim codecs As RasterCodecs = New RasterCodecs() 
   Dim srcFileName As String = Path.Combine(LEAD_VARS.ImagesDir, "Image1.cmp") 
   Dim destFileName As String = Path.Combine(LEAD_VARS.ImagesDir, "Image1_AddColorRgbRangeToRegion.bmp") 
   ' Load the image 
   Dim image As RasterImage = codecs.Load(srcFileName) 
   ' Add the region 
   Dim lowerColor As RasterColor = New RasterColor(0, 1, 0) 
   Dim upperColor As RasterColor = New RasterColor(0, 255, 0) 
   image.AddColorRgbRangeToRegion(lowerColor, upperColor, RasterRegionCombineMode.Set) 
   ' Draw something on the image 
   Dim command As InvertCommand = New InvertCommand() 
   ' Save the image 
   codecs.Save(image, destFileName, RasterImageFormat.Bmp, 24) 
End Sub 
Public NotInheritable Class LEAD_VARS 
   Public Const ImagesDir As String = "C:\LEADTOOLS21\Resources\Images" 
End Class 

Target Platforms

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