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Threshold Property (ShadowCommand)

Summary

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

Syntax

WinRT C#

C++

public int Threshold {get; set;}

Public Property Threshold As Integer

public int Threshold {get; set;}

get_Threshold(); 
set_Threshold(value); 
Object.defineProperty('Threshold');

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

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

Refer to ShadowCommand.

Requirements

Target Platforms

See Also