Threshold Property

Summary

Gets or sets a threshold value used to determine which pixels will be affected.

Syntax

C++/CLI

Python

public int Threshold { get; set; }

            public: 
property int Threshold { 
   int get(); 
   void set (    int ); 
}

Threshold # get and set (ShadowCommand)

Property Value

Threshold value used to determine which pixels will be affected. Valid values range from 0 through 255. When Type = ShadowCommandType.ColoredShadow, any component (R, G, or B) of a pixel with a value less than the Threshold value is not affected. When Type = ShadowCommandType.GrayShadow, any pixel where the master channel value is less than the Threshold value is not affected.

Remarks

In order to speed up widely used image processing filters in LEADTOOLS, the grayscale value (master channel) of a colored image is calculated using the following formulas:

#define CalcGrayValue(r, g, b) ((L_UCHAR)(((L_UCHAR) (((2 * (L_UINT) (r)) + (5 * (L_UINT) (g)) + (L_UINT) (b) + 4) / 8)))) 
#define CalcGrayValue16(r, g, b) ((L_UINT16) (((2 * (L_UINT32) (r)) + (5 * (L_UINT32) (g)) + (L_UINT32) (b) + 4) / 8)) 
#define CalcGrayValue32(r, g, b) ((L_UINT32) (((2 * (L_UINT32) (r)) + (5 * (L_UINT32) (g)) + (L_UINT32) (b) + 4) / 8))

Example

using Leadtools; 
using Leadtools.Codecs; 
using Leadtools.ImageProcessing.SpecialEffects; 
 
 
public void ShadowCommandExample() 
{ 
   // Load an image 
   RasterCodecs codecs = new RasterCodecs(); 
   codecs.ThrowExceptionsOnInvalidImages = true; 
 
   RasterImage image = codecs.Load(Path.Combine(LEAD_VARS.ImagesDir, "Master.jpg")); 
 
   // Prepare the command 
   ShadowCommand command = new ShadowCommand(); 
   command.Type = ShadowCommandType.GrayShadow; 
   command.Angle = ShadowCommandAngle.SouthEast; 
   command.Threshold = 0; 
   //Apply shadow effect  to the image. 
   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:\LEADTOOLS22\Resources\Images"; 
}

Requirements

Target Platforms

Reference

ShadowCommand Class

ShadowCommand Members

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Help Version 22.0.2023.3.31

Leadtools.ImageProcessing.SpecialEffects Assembly

Introduction

Getting Started

Namespaces

Leadtools.ImageProcessing.SpecialEffects Namespace

Assemblies