ClearNegativePixelsCommand Class

Summary

Sets all pixels with negative color values to 0.

Syntax

Objective-C

C++/CLI

Java

Python

public class ClearNegativePixelsCommand : RasterCommand

@interface LTClearNegativePixelsCommand : LTRasterCommand

public class ClearNegativePixelsCommand extends RasterCommand

public ref class ClearNegativePixelsCommand : public RasterCommand

class ClearNegativePixelsCommand(RasterCommand):

Remarks

If CodecsLoadOptions.Signed is true when a file is loaded, the image may contain negative pixel values and LEADTOOLS will paint/process the image incorrectly. In order to use this image correctly, you must user ClearNegativePixelsCommand. If the CodecsLoadOptions.Signed property is false, all negative pixels are cleared internally, during the load process.

Since some TIFF files are saved with negative values for pixel colors, you should use ClearNegativePixelsCommand if, after loading an image, RasterImage.Signed is true. ClearNegativePixelsCommand does nothing if RasterImage.IsSigned is false.

Programming tip: use ClearNegativePixelsCommand right after loading the image from file.

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

Example

This example sets the Signed flag in the load options, loads a tif file and clears the negative pixels.

using Leadtools; 
using Leadtools.Codecs; 
using Leadtools.ImageProcessing; 
 
 
public void ClearNegativePixelsCommandExample() 
{ 
	RasterCodecs codecs = new RasterCodecs(); 
 
	string srcFileName = Path.Combine(LEAD_VARS.ImagesDir, "Image1.cmp"); 
	string destFileName = Path.Combine(LEAD_VARS.ImagesDir, "CleanNegativePixelsCommand.tif"); 
 
	// Load the CMP file and convert it to TIF 
	RasterImage image = codecs.Load(srcFileName); 
	image.Signed = true; 
	codecs.Save(image, destFileName, RasterImageFormat.Tif, 24); 
	image.Dispose(); 
 
	// Load this image as signed 
	codecs.Options.Load.Signed = true; 
 
	// Load the source image from disk 
	image = codecs.Load(destFileName); 
	Assert.IsTrue(image.Signed); 
 
	// Clear the negative pixels and save it it back 
	ClearNegativePixelsCommand command = new ClearNegativePixelsCommand(); 
	command.Run(image); 
	Assert.IsTrue(!image.Signed); 
 
	codecs.Save(image, destFileName, RasterImageFormat.Tif, 24); 
 
	// Clean up 
	image.Dispose(); 
	codecs.Dispose(); 
} 
 
static class LEAD_VARS 
{ 
   public const string ImagesDir = @"C:\LEADTOOLS22\Resources\Images"; 
}

Requirements

Target Platforms

Reference

ClearNegativePixelsCommand Members

Leadtools.ImageProcessing Namespace

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Help Version 22.0.2023.5.16

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Leadtools Namespace

Leadtools.ImageProcessing Namespace

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