#include "l_bitmap.h"

L_LTIMGSFX_API L_INT L_AddShadowBitmap(pBitmap, uAngle, uThreshold, uFlags)


pointer to the bitmap handle

L_UINT uAngle;

shadow or light direction

L_UINT uThreshold;

threshold value

L_UINT uFlags;


Adds shadows to the bitmap.

Parameter Description
pBitmap Pointer to the bitmap handle that references the bitmap on which to apply the effect.
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 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.



The function was successful.

< 1

An error occurred. Refer to Return Codes.


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

This function supports 12 and 16-bit grayscale and 48 and 64-bit color images. Support for 12 and 16-bit grayscale and 48 and 64-bit color images is available in the Document and Medical Imaging toolkits.

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.

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.

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

*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


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


Win32, x64.

See Also


L_EdgeDetectorBitmap, L_LensFlareBitmap, L_LightBitmap, L_AllocFTArray, L_ChangeHueSatIntBitmap, L_ColorReplaceBitmap, L_ColorThresholdBitmap, L_DFTBitmap, L_DirectionEdgeStatisticalBitmap, L_FFTBitmap, L_FreeFTArray, L_FrqFilterBitmap, L_FrqFilterMaskBitmap, L_FTDisplayBitmap, L_GetBitmapStatisticsInfo, L_GetFeretsDiameter, L_GetObjectInfo, L_GetRgnContourPoints, L_GetRgnPerimeterLength, L_MathFunctionBitmap, L_RevEffectBitmap, L_SegmentBitmap, L_SubtractBackgroundBitmap, L_UserFilterBitmap, L_BricksTextureBitmap, L_DeskewBitmap, L_DiffuseGlowBitmap, L_GlowFilterBitmap, L_HalfTonePatternBitmap, L_HighPassFilterBitmap, L_MaskConvolutionBitmap, L_PerspectiveBitmap, L_PlasmaFilterBitmap, L_PointillistBitmap, L_CanvasBitmap, L_CloudsBitmap, L_ColoredBallsBitmap, L_DiffuseGlowBitmap, L_DisplaceMapBitmap, L_FragmentBitmap, L_MosaicTilesBitmap, L_OffsetBitmap, L_RomanMosaicBitmap, L_VignetteBitmap, L_ZigZagBitmap


Raster Image Functions: Artistic Effects


Applying Artistic Effects


L_INT AddShadowBitmapExample(L_VOID) 
   L_INT nRet; 
   BITMAPHANDLE LeadBitmap;   /* Bitmap handle for the image */ 
   /* Load a bitmap at its own bits per pixel  */ 
   nRet = L_LoadBitmap(MAKE_IMAGE_PATH(TEXT("ImageProcessingDemo\\Image3.cmp")), &LeadBitmap, sizeof(BITMAPHANDLE), 0, ORDER_BGR, NULL, NULL); 
   if(nRet !=SUCCESS) 
      return nRet; 
   /* Apply  shadow effect  to the image*/ 
   nRet = L_AddShadowBitmap(&LeadBitmap, SHADOW_SE, 0, SHADOW_CLR_GRAY); 
   if(nRet !=SUCCESS) 
      return nRet; 
   nRet = L_SaveBitmap(MAKE_IMAGE_PATH(TEXT("Result.BMP")), &LeadBitmap, FILE_BMP, 24, 0, NULL); 
   if(nRet !=SUCCESS) 
      return nRet; 
   //free bitmap  
   return SUCCESS; 

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