Selects a specified number of bits of an 8, 12 or 16-bit grayscale bitmap and puts them into a mask, then colors the bitmap depending on the mask. This can show bitmap variances depending on user-defined conditions.


#include "l_bitmap.h"

L_LTIMGCOR_API L_INT L_SelectBitmapData (pDstBitmap, pSrcBitmap, crColor, uSrcLowBit, uSrcHighBit, uThreshold, bCombine, uFlags)



Pointer to the destination bitmap that will contain the result of the function. This bitmap will be updated as a 24-bit RGB. The bitmap is assumed to be uninitialized, so you should free the bitmap before passing it to the function.


Pointer to the bitmap handle referencing the 8, 12 or 16-bit grayscale bitmap. pSrcBitmap will not be affected.


Color that will be used for showing the variances in the bitmap.

L_UINT uSrcLowBit

Position of the start bit that will construct the mask. The position is a zero based number.

L_UINT uSrcHighBit

Position of the end bit that will construct the mask. This is inclusive (it is part of the mask). The value should not be less than uSrcLowBit. You can also pass 1, which is interpreted as "highest bit" (pSrcBitmap->BitsPerPixel 1).

L_UINT uThreshold

Value that indicates the threshold for showing the bitmap variances. If the mask value is greater or equal to the threshold value then the pixel will be colored using crColor. See bCombine for more details.

L_BOOL bCombine

A flag which tells how to color the output pixels:

L_UINT32 uFlags

Reserved for future use. Must be 0.


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


This function can process the whole image or a region of the image. If a bitmap has a region, the effect is applied only to the region.

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, Linux.

See Also




This example loads a bitmap and applies Selecting.

L_INT SelectBitmapDataExample(L_VOID) 
   L_INT nRet; 
   BITMAPHANDLE LeadBitmap;   /* Bitmap handle to hold the loaded image. */ 
   BITMAPHANDLE DstBitmap;     /* Bitmap handle to hold the result. */ 
   /* Load the bitmap, keeping the bits per pixel of the file */ 
   nRet = L_LoadBitmap(MAKE_IMAGE_PATH(TEXT("Slice.tif")), &LeadBitmap, sizeof(BITMAPHANDLE), 0, ORDER_BGRORGRAY, NULL, NULL); 
   if (nRet != SUCCESS) 
      return nRet; 
   // Call the function 
   nRet = L_SelectBitmapData(&DstBitmap, 
      RGB(233, 10, 77), 
      2 /* uSrcLowBit */, 
      6 /* uSrcHighBit */, 
      25 /* uThreshold */, 
      TRUE, 0); 
   if (nRet != SUCCESS) 
      return nRet; 
   // Now we have the resulted image in DstBitmap 
   nRet = L_SaveBitmap(MAKE_IMAGE_PATH(TEXT("Result.BMP")), &DstBitmap, FILE_BMP, 24, 0, NULL); 
   if (nRet != SUCCESS) 
      return nRet; 
   //free bitmap 
   if (DstBitmap.Flags.Allocated) 
   if (LeadBitmap.Flags.Allocated) 
   return SUCCESS; 

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LEADTOOLS Raster Imaging C API Help

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© 1991-2023 LEAD Technologies, Inc. All Rights Reserved.