#include "l_bitmap.h"

L_LTIMGSFX_API L_INT L_FreeHandShearBitmap (pBitmap, pAmplitudes, uAmplitudesCount, uScale, crFill, uFlags)

Shears the bitmap by the wave drawn using pAmplitudes.



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

L_INT *pAmplitudes

Array of integers that represent shear wave values. The real values of the array elements is divided by 1000, and the valid value of each element in pAmplitudes array is between 1000 and 1000. These values are generally obtained from the L_GetCurvePoints function. They may also be obtained through the Wave Shear Dialog.

L_UINT uAmplitudesCount

Number of entries in the pAmplitudes array.

L_UINT uScale

Factor used to increase or decrease the various amplitude values in the pAmplitudes array. Each value in the pAmplitudes array is multiplied by this factor. The real factor value is the uScale value divided by 100. The valid range is from 0 to 100.


The COLORREF value that specifies the fill color for any exposed areas. You can specify a COLORREF value, such as the return value of the Windows RGB macro, or you can use the PALETTEINDEX macro to specify a palette color.

L_UINT uFlags

Flags that indicate how to handle exposed areas, and the direction of the shear wave. You can use a bit wise OR (|) to specify one flag from each group.

The following are the flags that indicate how to handle the exposed areas:

Value Meaning
FILL_CLR [0x0000] Fill any exposed areas with crFill.
FILL_RPT [0x0001] Stretch the image edges to fill the exposed area.
FILL_NOCHG [0x0002] Leave the exposed area as is, without changing it.

The following are the flags that indicate the direction of the shear wave:

Value Meaning
SHR_HORZ [0x0000] Apply the shear wave horizontally.
SHR_VERT [0x0010] Apply the shear wave vertically.


Value Meaning
SUCCESS The function was successful.
< 1 An error occurred. Refer to Return Codes.


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 will shear the bitmap using the wave in the pAmplitudes array. The wave can be applied vertically or horizontally. The pAmplitude data can be obtained from the L_GetCurvePoints function, or from the Wave Shear Dialog.

If the bitmap has a region, the effect will be applied on the region only.

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.

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

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.

Required DLLs and Libraries


Win32, x64.

See Also




This example will shear the bitmap using a triangular wave

L_INT FreeHandShearBitmapExample(L_VOID) 
   L_INT nRet; 
   BITMAPHANDLE LeadBitmap;   /* Bitmap handle for the image */ 
   POINT apUserPoint [4]; 
   L_INT pAmplitudes[13]; 
   L_INT nMax, i; 
   /* Load a bitmap at its own bits per pixel  */ 
   nRet = L_LoadBitmap(MAKE_IMAGE_PATH(TEXT("sample5.cmp")), &LeadBitmap, sizeof(BITMAPHANDLE), 0, ORDER_BGR, NULL, NULL); 
   if(nRet !=SUCCESS) 
      return nRet; 
   /*Fill apUserPoint array with points that define a triangular wave*/ 
   apUserPoint [0].x = 0; 
   apUserPoint [0].y = 0; 
   apUserPoint [1].x = 3; 
   apUserPoint [1].y = 10; 
   apUserPoint [2].x = 9; 
   apUserPoint [2].y = -10; 
   apUserPoint [3].x = 12; 
   apUserPoint [3].y = 0; 
   /*Draw a triangular wave according to apUserPoint points and store the amplitude values in the pAmplitudes array*/ 
   nRet = L_GetCurvePoints(pAmplitudes, apUserPoint, 4, NULL, GUB_LINEAR); 
   if(nRet !=SUCCESS) 
      return nRet; 
   /*Normalize pAmplitudes (maximum value in pAmplitudes is 1000 and lower is -1000)*/ 
   nMax = 0; 
   for(i = 0; i <  13; i++) 
      if(nMax < pAmplitudes [i]) 
         nMax =  pAmplitudes [i]; 
      for(i = 0; i <  13; i++) 
          pAmplitudes [i] = (1000 * pAmplitudes [i] / abs(nMax)); 
   /* Apply the shear wave horizontally */ 
   nRet = L_FreeHandShearBitmap (&LeadBitmap, pAmplitudes, 13, 100, 0, FILL_RPT | SHR_HORZ); 
   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; 

Help Version 21.0.2021.4.7
Products | Support | Contact Us | Intellectual Property Notices
© 1991-2021 LEAD Technologies, Inc. All Rights Reserved.

LEADTOOLS Raster Imaging C API Help