RemapHueCommand Class

Summary

Uses a lookup table to change an image's hue values. The saturation and value tables change S and V values only if a particular hue value is marked as non-zero in the Mask property. It is used for all resolutions, including 48 and 64-bit images.

Syntax

Objective-C

C++

Java

public class RemapHueCommand : RasterCommand

Public Class RemapHueCommand  
   Inherits RasterCommand

@interface LTRemapHueCommand : LTRasterCommand

public class RemapHueCommand extends RasterCommand

public ref class RemapHueCommand : public RasterCommand

Remarks

This command can be used to change a range of colors to another range of colors. For example, it could be used to change all red pixels to any color, where a red pixel can have any brightness (V) and any amount of white (saturation). A red pixel in this case would be RGB(x,y,y) where 0 <= x <(LookUpTableLength - 1) and 0 <= y < x or in the HSV color space HSV(0,x,x) where 0<=x<=(LookUpTableLength - 1)
The Mask lookup table identifies which values in the HueTable are valid. If a Mask value is 0, then the corresponding value in the HueTable is ignored. If a Mask value is non-zero, then the corresponding value in the HueTable is used. For example, if a pixel has a hue value of 240 and Mask[240] is nonzero, then the hue value of 240 is replaced with HueTable[240]. Traditionally, hue ranges from 0 to 359. For the lookup table, the range of 0 to 359 is remapped to a range of 0.. LookUpTableLength - 1. For example, if LookUpTableLength = 256
This command supports 48 and 64-bit colored images.
This command does not support signed data images.
This command does not support 32-bit grayscale images.

For more information, refer to Changing Brightness and Contrast.

Example

Run the RemapHueCommand on an image and change all green hues (and hues near green).

using Leadtools; 
using Leadtools.Codecs; 
using Leadtools.ImageProcessing.Color; 
 
public int INCREMENT_S1(int x, int Length) 
{ 
   return ((x + 1) % Length); 
} 
 
public int DECREMENT_S1(int x, int Length) 
{ 
   return ((x + (Length - 1)) % Length); 
} 
 
public int ADD_S1(int x, int y, int Length) 
{ 
   return ((x + y) % Length); 
} 
 
public void RemapHueCommandCommandExample() 
{ 
   // Load an image 
   RasterCodecs codecs = new RasterCodecs(); 
   codecs.ThrowExceptionsOnInvalidImages = true; 
 
   RasterImage image = codecs.Load(Path.Combine(LEAD_VARS.ImagesDir, "cannon.jpg")); 
 
   // Prepare the command 
   int[] MaskTable; 
   int[] HueTable; 
   RasterHsvColor hsvRef; 
   int HueGreen, HueChange; 
   int Change; 
   int i, Count; 
   int Length; 
 
   if (image.BitsPerPixel >= 48) 
      Length = 0x10000; 
   else if (!(image.BitsPerPixel == 16 || image.BitsPerPixel == 12)) 
      Length = 256; 
   else if (image.GetLookupTable() != null && image.UseLookupTable) 
      Length = 256; 
   else 
      Length = (1 << image.BitsPerPixel); 
 
   //Allocate tables 
   MaskTable = new int[Length]; 
   HueTable = new int[Length]; 
 
   //Initialize tables 
   for (i = 0; i < Length; i++) 
   { 
      MaskTable[i] = 0; 
      HueTable[i] = i; 
   } 
 
   //Get the hue for green 
   hsvRef = RasterHsvColor.FromRasterColor(new RasterColor(0, 255, 0)); 
 
   HueGreen = hsvRef.H; 
 
   //Obtain new hue   
   hsvRef = RasterHsvColor.FromRasterColor(new RasterColor(255, 128, 0)); 
   Change = (int)hsvRef.H - (int)HueGreen; 
   HueChange = (Change > 0) ? (int)Change : (int)(Change + Length - 1); 
   HueGreen *= (Length - 1) / 255; 
   HueChange *= (Length - 1) / 255; 
 
   //Set values in HueTable, MaskTable  
   HueTable[HueGreen] = (HueTable[HueGreen] + HueChange); 
   MaskTable[HueGreen] = 1; 
 
   //set the hues near green (+/- 15) 
   Count = (15 * (Length - 1)) / 255; 
   for (i = INCREMENT_S1(HueGreen, Length); Count > 0; i = INCREMENT_S1(i, Length), Count--) 
   { 
      HueTable[i] = ADD_S1(HueTable[i], HueChange, Length); 
      MaskTable[i] = 1; 
   } 
 
   Count = (15 * (Length - 1)) / 255; 
   for (i = DECREMENT_S1(HueGreen, Length); Count > 0; i = DECREMENT_S1(i, Length), Count--) 
   { 
      HueTable[i] = ADD_S1(HueTable[i], HueChange, Length); 
      MaskTable[i] = 1; 
   } 
 
   RemapHueCommand command = new RemapHueCommand(MaskTable, HueTable, null, null, Length); 
   command.Run(image); 
   codecs.Save(image, Path.Combine(LEAD_VARS.ImagesDir, "Result.jpg"), RasterImageFormat.Jpeg, 24); 
 
} 
 
static class LEAD_VARS 
{ 
   public const string ImagesDir = @"C:\Users\Public\Documents\LEADTOOLS Images"; 
}

Imports Leadtools 
Imports Leadtools.Codecs 
Imports Leadtools.ImageProcessing.Color 
 
Public Function INCREMENT_S1(ByVal x As Integer, ByVal Length As Integer) As Integer 
   Return ((x + 1) Mod Length) 
End Function 
 
Public Function DECREMENT_S1(ByVal x As Integer, ByVal Length As Integer) As Integer 
   Return ((x + (Length - 1)) Mod Length) 
End Function 
 
Public Function ADD_S1(ByVal x As Integer, ByVal y As Integer, ByVal Length As Integer) As Integer 
   Return ((x + y) Mod Length) 
End Function 
 
Public Sub RemapHueCommandCommandExample() 
   Dim codecs As New RasterCodecs() 
   codecs.ThrowExceptionsOnInvalidImages = True 
 
   Dim leadImage As RasterImage = codecs.Load(Path.Combine(LEAD_VARS.ImagesDir, "cannon.jpg")) 
 
   ' Prepare the command 
   Dim MaskTable() As Integer 
   Dim HueTable() As Integer 
   Dim hsvRef As RasterHsvColor 
   Dim HueGreen As Integer 
   Dim HueChange As Integer 
 
   Dim Change As Integer 
   Dim i As Integer 
   Dim Count As Integer 
   Dim Length As Integer 
 
   If (leadImage.BitsPerPixel >= 48) Then 
 
      Length = 65536 
 
   ElseIf (Not (leadImage.BitsPerPixel = 16 Or leadImage.BitsPerPixel = 12)) Then 
      Length = 256 
   ElseIf (IsNothing(leadImage.GetLookupTable) And leadImage.UseLookupTable) Then 
      Length = 256 
   Else 
      Length = (1 << leadImage.BitsPerPixel) 
   End If 
   'Allocate tables 
   ReDim MaskTable(Length - 1) 
   ReDim HueTable(Length - 1) 
 
   'Initialize tables 
   For i = 0 To Length - 1 
      MaskTable(i) = 0 
      HueTable(i) = i 
   Next 
 
   'Get the hue for green 
   hsvRef = RasterHsvColor.FromRasterColor(New RasterColor(0, 255, 0)) 
 
   HueGreen = hsvRef.H 
 
   'Obtain new hue   
   hsvRef = RasterHsvColor.FromRasterColor(New RasterColor(255, 128, 0)) 
   Change = hsvRef.H - HueGreen 
   If (Change > 0) Then 
      HueChange = Change 
   Else 
      HueChange = Change + Length - 1 
   End If 
 
   HueGreen = (HueGreen * (Length - 1)) \ 255 
   HueChange = (HueChange * (Length - 1)) \ 255 
 
   'Set values in HueTable, MaskTable  
   HueTable(HueGreen) = HueTable(HueGreen) + HueChange 
   MaskTable(HueGreen) = 1 
 
   'set the hues near green (+/- 15) 
   i = INCREMENT_S1(HueGreen, Length) 
 
   For Count = (15 * (Length - 1)) \ 255 To 1 Step -1 
      i = INCREMENT_S1(i, Length) 
      HueTable(i) = ADD_S1(HueTable(i), HueChange, Length) 
      MaskTable(i) = 1 
   Next 
 
   i = DECREMENT_S1(HueGreen, Length) 
 
   For Count = (15 * (Length - 1)) \ 255 To 1 Step -1 
 
      i = DECREMENT_S1(i, Length) 
      HueTable(i) = ADD_S1(HueTable(i), HueChange, Length) 
      MaskTable(i) = 1 
   Next 
   Dim command As RemapHueCommand = New RemapHueCommand(MaskTable, HueTable, Nothing, Nothing, Length) 
 
   command.Run(leadImage) 
   codecs.Save(leadImage, Path.Combine(LEAD_VARS.ImagesDir, "Result.jpg"), RasterImageFormat.Jpeg, 24) 
 
End Sub 
 
Public NotInheritable Class LEAD_VARS 
   Public Const ImagesDir As String = "C:\Users\Public\Documents\LEADTOOLS Images" 
End Class

c#[Silverlight C# Example] 
using Leadtools; 
using Leadtools.Codecs; 
using Leadtools.ImageProcessing.Color; 
using Leadtools.Examples; 
 
public int INCREMENT_S1(int x, int Length) 
{ 
   return ((x + 1) % Length); 
} 
 
public int DECREMENT_S1(int x, int Length) 
{ 
   return ((x + (Length - 1)) % Length); 
} 
 
public int ADD_S1(int x, int y, int Length) 
{ 
   return ((x + y) % Length); 
} 
 
public void RemapHueCommandCommandExample(RasterImage image, Stream outStream) 
{ 
   // Prepare the command 
   int[] MaskTable; 
   int[] HueTable; 
   RasterHsvColor hsvRef; 
   int HueGreen, HueChange; 
   int Change; 
   int i, Count; 
   int Length; 
 
   if (image.BitsPerPixel >= 48) 
      Length = 0x10000; 
   else if (!(image.BitsPerPixel == 16 || image.BitsPerPixel == 12)) 
      Length = 256; 
   else if (image.GetLookupTable() != null && image.UseLookupTable) 
      Length = 256; 
   else 
      Length = (1 << image.BitsPerPixel); 
 
   //Allocate tables 
   MaskTable = new int[Length]; 
   HueTable = new int[Length]; 
 
   //Initialize tables 
   for (i = 0; i < Length; i++) 
   { 
      MaskTable[i] = 0; 
      HueTable[i] = i; 
   } 
 
   //Get the hue for green 
   hsvRef = RasterHsvColor.FromRasterColor(new RasterColor(0, 255, 0)); 
 
   HueGreen = hsvRef.H; 
 
   //Obtain new hue   
   hsvRef = RasterHsvColor.FromRasterColor(new RasterColor(255, 128, 0)); 
   Change = hsvRef.H - HueGreen; 
   HueChange = (Change > 0) ? Change : (Change + Length - 1); 
   HueGreen *= (Length - 1) / 255; 
   HueChange *= (Length - 1) / 255; 
 
   //Set values in HueTable, MaskTable  
   HueTable[HueGreen] = (HueTable[HueGreen] + HueChange); 
   MaskTable[HueGreen] = 1; 
 
   //set the hues near green (+/- 15) 
   Count = (15 * (Length - 1)) / 255; 
   for (i = INCREMENT_S1(HueGreen, Length); Count > 0; i = INCREMENT_S1(i, Length), Count--) 
   { 
      HueTable[i] = ADD_S1((int)HueTable[i], HueChange, Length); 
      MaskTable[i] = 1; 
   } 
 
   Count = (15 * (Length - 1)) / 255; 
   for (i = DECREMENT_S1(HueGreen, Length); Count > 0; i = DECREMENT_S1(i, Length), Count--) 
   { 
      HueTable[i] = ADD_S1(HueTable[i], HueChange, Length); 
      MaskTable[i] = 1; 
   } 
 
   RemapHueCommand command = new RemapHueCommand(MaskTable, HueTable, null, null, Length); 
   command.Run(image); 
 
   // Save result image 
   RasterCodecs codecs = new RasterCodecs(); 
   codecs.Save(image, outStream, RasterImageFormat.Jpeg, 24); 
   image.Dispose(); 
} 
vb[Silverlight VB Example] 
Imports Leadtools 
Imports Leadtools.Codecs 
Imports Leadtools.ImageProcessing.Color 
 
Public Function INCREMENT_S1(ByVal x As Integer, ByVal Length As Integer) As Integer 
   Return ((x + 1) Mod Length) 
End Function 
 
Public Function DECREMENT_S1(ByVal x As Integer, ByVal Length As Integer) As Integer 
   Return ((x + (Length - 1)) Mod Length) 
End Function 
 
Public Function ADD_S1(ByVal x As Integer, ByVal y As Integer, ByVal Length As Integer) As Integer 
   Return ((x + y) Mod Length) 
End Function 
 
Public Sub RemapHueCommandCommandExample(ByVal image As RasterImage, ByVal outStream As Stream) 
   ' Prepare the command 
   Dim MaskTable As Integer() 
   Dim HueTable As Integer() 
   Dim hsvRef As RasterHsvColor 
   Dim HueGreen, HueChange As Integer 
   Dim Change As Integer 
   Dim i, Count As Integer 
   Dim Length As Integer 
 
   If image.BitsPerPixel >= 48 Then 
      Length = &H10000 
   ElseIf Not (image.BitsPerPixel = 16 OrElse image.BitsPerPixel = 12) Then 
      Length = 256 
   ElseIf Not image.GetLookupTable() Is Nothing AndAlso image.UseLookupTable Then 
      Length = 256 
   Else 
      Length = (1 << image.BitsPerPixel) 
   End If 
 
   'Allocate tables 
   MaskTable = New Integer(Length - 1) {} 
   HueTable = New Integer(Length - 1) {} 
 
   'Initialize tables 
   i = 0 
   Do While i < Length 
      MaskTable(i) = 0 
      HueTable(i) = i 
      i += 1 
   Loop 
 
   'Get the hue for green 
   hsvRef = RasterHsvColor.FromRasterColor(New RasterColor(0, 255, 0)) 
 
   HueGreen = hsvRef.H 
 
   'Obtain new hue   
   hsvRef = RasterHsvColor.FromRasterColor(New RasterColor(255, 128, 0)) 
   Change = hsvRef.H - HueGreen 
   If (Change > 0) Then 
      HueChange = Change 
   Else 
      HueChange = (Change + Length - 1) 
   End If 
   HueGreen *= (Length - 1) / 255 
   HueChange *= (Length - 1) / 255 
 
   'Set values in HueTable, MaskTable  
   HueTable(HueGreen) = (HueTable(HueGreen) + HueChange) 
   MaskTable(HueGreen) = 1 
 
   'set the hues near green (+/- 15) 
   Count = (15 * (Length - 1)) / 255 
   i = INCREMENT_S1(HueGreen, Length) 
   Do While Count > 0 
      HueTable(i) = ADD_S1(CInt(HueTable(i)), HueChange, Length) 
      MaskTable(i) = 1 
      i = INCREMENT_S1(i, Length) 
      Count -= 1 
   Loop 
 
   Count = (15 * (Length - 1)) / 255 
   i = DECREMENT_S1(HueGreen, Length) 
   Do While Count > 0 
      HueTable(i) = ADD_S1(HueTable(i), HueChange, Length) 
      MaskTable(i) = 1 
      i = DECREMENT_S1(i, Length) 
      Count -= 1 
   Loop 
 
   Dim command As RemapHueCommand = New RemapHueCommand(MaskTable, HueTable, Nothing, Nothing, Length) 
   command.Run(image) 
 
   ' Save result image 
   Dim codecs As RasterCodecs = New RasterCodecs() 
   codecs.Save(image, outStream, RasterImageFormat.Jpeg, 24) 
   image.Dispose() 
End Sub