FILESAVECALLBACK Function

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#include "l_bitmap.h"

L_INT pEXT_CALLBACK YourFunction (pBitmap, pBuffer, uRow, uLines, pUserData)

pBITMAPHANDLE pBitmap;	/* pointer to the bitmap handle */
L_UCHAR* pBuffer;	/* pointer to a buffer for the caller's input data */
L_UINT uRow;	/* first line to write to the buffer*/
L_UINT uLines;	/* number of lines to write to the buffer */
L_VOID* pUserData;	/* pointer to additional parameters */

Provides input to the L_SaveFile or L_SaveFileOffset function.

Parameter	Description
pBitmap	Pointer to the bitmap handle that contains the image information.
pBuffer	Pointer to the caller's input buffer where the callback function must put the data.
uRow	The number of the first line that the callback function must put in the buffer.
uLines	The number of lines that the callback function must put in the buffer.
pUserData	A void pointer that you can use to access a variable or structure containing data that your callback function needs. This gives you a way to receive data indirectly from the function that uses this callback function. (This is the same pointer that you pass in the pUserData parameter of the calling function.)
	Keep in mind that this is a void pointer, which must be cast to the appropriate data type within your callback function.

Returns

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

Comments

This type callback function is optional. If you provide a callback function, it must supply the image data. It can also do other useful things, such as updating a status bar. If you do not provide a callback function, the calling function saves data from the specified bitmap.

Required DLLs and Libraries

LTFIL

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

See Also

Functions:

L_SaveFile, L_SaveFileOffset, L_StartCompressBuffer

Example

This FILESAVECALLBACK function supplies image data from the LEAD bitmap to fulfill the minimum requirements of the callback

L_INT EXT_CALLBACK SaveImageCB (pBITMAPHANDLE pBitmap,
                                L_UCHAR     * pBuffer,
                                L_UINT        nRowBegin,
                                L_UINT        nRowsToGet,
                                L_VOID       * pUserData)
{
   UNREFERENCED_PARAMETER(pUserData);

   L_UINT i; /* Row counter */
   L_UINT nRowLast = nRowBegin + nRowsToGet; /* Used when counting rows */

   /* Put the required rows in the buffer */
   for (i = nRowBegin; i < nRowLast; i++)
   {
      /* Get a row from the bitmap and put it in the buffer */
      L_AccessBitmap (pBitmap);
      L_GetBitmapRow (pBitmap, pBuffer, i, pBitmap->BytesPerLine);
      L_ReleaseBitmap (pBitmap);
      
      /* Move the pointer to the position in the buffer for the next row */
      pBuffer += pBitmap->BytesPerLine;
   }
   return (SUCCESS);
}