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AddColorHsvRangeToRegion Method

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


Specifies the minimum (inclusive) R, G and B values. A pixel must have H,S, and V 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 H,S, and V 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 HSV color model to set a region based on a color range.

It is useful for identifying all shades of a certain color. For example, this method could be used to set a region of all green colors including:

RGB(0,2,0) RGB(1,2,1)
RGB(0,1,0) -
RGB(0,3,0) RGB(1,3,1) RGB(2,3,2)
RGB(0,255,0) RGB(1,255,1) RGB(2,255,2)

The diagram below shows how S and V affect the color green (H = 85):

Hue Table

To be added to the region a color must fall in the range lowerColor... upperColor. If you want to set a region for all red (and colors near red), you could specify lowerColor and upperColor as follows:

lowerColor (250,1,1) upperColor (5,255,255)

The hue for the lowerColor is 250 and the hue for the upperColor is 5. For the hue to fall in this range it must be 250, 251, 252, 253, 254, 255, 1, 2, 3, 4, or 5. Note that the values for hue wrap from 255 to 1.

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 does not support signed data 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.


This example will load an image, adds a region corresponding to all pure green (Hue = 85) and colors near green (+/- 10), 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 AddColorHsvRangeToRegionExample() 
	RasterCodecs codecs = new RasterCodecs(); 
	string srcFileName = Path.Combine(LEAD_VARS.ImagesDir, "Image1.cmp"); 
	string destFileName = Path.Combine(LEAD_VARS.ImagesDir, "Image1_AddColorHsvRangeToRegion.bmp"); 
	// Load the image 
	RasterImage image = codecs.Load(srcFileName); 
	// Add the region 
	RasterHsvColor lowerColor = new RasterHsvColor(75, 40, 40); 
	RasterHsvColor upperColor = new RasterHsvColor(95, 255, 255); 
	image.AddColorHsvRangeToRegion(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 AddColorHsvRangeToRegionExample() 
   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_AddColorHsvRangeToRegion.bmp") 
   ' Load the image 
   Dim image As RasterImage = codecs.Load(srcFileName) 
   ' Add the region 
   Dim lowerColor As RasterHsvColor = New RasterHsvColor(75, 40, 40) 
   Dim upperColor As RasterHsvColor = New RasterHsvColor(95, 255, 255) 
   image.AddColorHsvRangeToRegion(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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