LBitmap::AddShadow

#include "ltwrappr.h"

virtual L_INT LBitmap::AddShadow (uAngle, uThreshold, uFlags)

L_UINT uAngle;

shadow or light direction

L_UINT uThreshold;

threshold value

L_UINT uFlags;

flag

Adds shadows to the bitmap.

Parameter Description
uAngle Angle value indicating the direction of the light source producing the shadow. Possible values are:
  Value Meaning
  SHADOW_E [0] East
  SHADOW_NE [1] Northeast
  SHADOW_N [2] North
  SHADOW_NW [3] Northwest
  SHADOW_W [4] West
  SHADOW_SW [5] Southwest
  SHADOW_S [6] South
  SHADOW_SE [7] Southeast
uThreshold Threshold value used to determine which pixels will be affected . Valid values range from 0 through 65535 for 64-bit, 48-bit and 16-bit grayscale images and from 0 through 4095 for 12-bit grayscale images. Otherwise, it is from 0 through 255. When uFlags = COLOR_RGB, any component (R, G, or B) of a pixel with a value less than the uThreshold value is not affected. When uFlags = COLOR_GRAY, any pixel where the master channel value</b>* is less than the uThreshold value is not affected.
uFlags Type of the shadow. Possible values are:
  Value Meaning
  SHADOW_CLR_RGB [0] Shadows are colored.
  SHADOW_CLR_GRAY [1] Shadows are grayscale.

Returns

SUCCESS

The function was successful.

< 1

An error occurred. Refer to Return Codes.

Comments

This function applies a convolution matrix upon each color component and then combines the results in order to add shadows.

Support for 12- and 16-bit grayscale and 48- and 64-bit color images is available only in the Document/Medical toolkits.

This function does not support signed data images. It returns the error code ERROR_SIGNED_DATA_NOT_SUPPORTED if a signed data image is passed to this function.

This function does not support 32-bit grayscale images. It returns the error code ERROR_GRAY32_UNSUPPORTED if a 32-bit grayscale image is passed to this function.

To update a status bar or detect a user interrupt during execution of this function, refer to LBase::EnableStatusCallback.

Calculating Master Channel Values

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)) 

Required DLLs and Libraries

LTIMGSFX

For a listing of the exact DLLs and Libraries needed, based on the toolkit version, refer to Files To Be Included With Your Application.

Platforms

Win32, x64.

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