L_LTIMGCOR_API L_INT L_DotRemoveBitmap(pBitmap, pDotRemove, pfnCallback, pUserData, uFlags)
Finds and removes dots and specks of various sizes.
Pointer to the bitmap handle referencing the bitmap from which to remove dots.
Pointer to the DOTREMOVE structure that LEADTOOLS uses to remove dots.
Optional callback function for additional processing.
If you do not provide a callback function, use NULL as the value of this parameter.
If you do provide a callback function, use the function pointer as the value of this parameter.
The callback function must adhere to the function prototype described in DOTREMOVECALLBACK Function.
Void pointer that you can use to pass one or more additional parameters that the callback function needs.
To use this feature, assign a value to a variable or create a structure that contains as many fields as you need. Then, in this parameter, pass the address of the variable or structure, casting it to L_VOID *. The callback function, which receives the address in its own pUserData parameter, can cast it to a pointer of the appropriate data type to access your variable or structure.
If the additional parameters are not needed, you can pass NULL in this parameter.
Reserved for future use. Must be 0.
|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.
(Document) This function finds and removes dots, specks, and blobs of various sizes in 1-bit documents. The dots, specks, and blobs may or may not be all black. The behavior of this function can be modified by using its callback.
This function works only on 1-bit black and white images.
If a region is selected, only the selected region will be changed by this function. If no region is selected, the whole image will be processed.
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.
This example returns a region of all 1x1 to 3x3 specks that are solid black
If a speck has any white pixels, it is NOT part of the returned region
The call is configured to return a single LEAD region corresponding to all changes
The image itself is unchanged
A callback is used to display information about each speck that is removed
The callback does NOT return a region
L_INT EXT_CALLBACK ExampleDotRemoveCB(HRGN hRgn, PRECT pBoundingRect, L_INT32 iWhiteCount, L_INT32 iBlackCount, L_VOID *pUserData)
TEXT("Region Bounds: left=%d, right=%d, top=%d, bottom=%d \n"),
rcRect.left, rcRect.right, rcRect.top, rcRect.bottom);
pBoundingRect->right - pBoundingRect->left,
pBoundingRect->bottom - pBoundingRect->top,
//Do not remove the speck if it contains any white pixels
if (iWhiteCount > 0)
nRet = SUCCESS_NOREMOVE;
nRet = SUCCESS_REMOVE;
L_INT DotRemoveBitmapExample(pBITMAPHANDLE pBitmap)
memset(&BitmapRegion, 0, sizeof(BITMAPHANDLE));
dr.uStructSize = sizeof(DOTREMOVE);
dr.iMinDotWidth = 6;
dr.iMinDotHeight = 6;
dr.iMaxDotWidth = 8;
dr.iMaxDotHeight = 8;
dr.uFlags = DOT_USE_SIZE | DOT_SINGLE_REGION | DOT_LEAD_REGION | DOT_CALLBACK_REGION;
dr.pBitmapRegion = &BitmapRegion;
dr.uBitmapStructSize = sizeof(BITMAPHANDLE);
nRet = L_DotRemoveBitmap(
if (nRet == SUCCESS)
//Delete the existing region
L_GetBitmapRgnBounds(dr.pBitmapRegion, NULL, &rectRgn);
L_CopyBitmapHandle(pBitmap, dr.pBitmapRegion, sizeof(BITMAPHANDLE));
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