L_ConvertBufferExt

#include "l_bitmap.h"

L_LTKRN_API L_INT L_ConvertBufferExt(pBuffer, nWidth, nBitsPerPixelSrc, nBitsPerPixelDst, nOrderSrc, nOrderDst, pPaletteSrc, pPaletteDst, uFlags, uLowBit, uHighBit)

Converts data in the specified buffer to the specified bits per pixel and color order. You can convert from any bits per pixel to any bits per pixel.

Returns

Comments

Note: This function will also work for 12, 16 and 32-bit grayscale images, but only in the Document and Medical Imaging toolkits. If you attempt to use this function with a 12, 16 or 32-bit grayscale image, but you do not have a Medical Imaging edition, you will receive an error.

The conversion uses only one buffer, which must be large enough to hold the data before and after conversion.

Image data that is 8 bits per pixel or less must use a palette, and this function can use such data as input, output, or both. Therefore, you may need to specify the palette for the input, or for the output, or both.

If either nBitsPerPixelSrc or nBitsPerPixelDst is 16 or 32, uFlags is used to determine whether the data should be treated as color or grayscale.

If nBitsPerPixelSrc is 12, it is assumed to be grayscale. However, the uFlags parameter should also reflect that it is grayscale for future compatibility.

If the source is grayscale (other than 32-bit), pPaletteSrc can be set to a palette. The palette should contain N entries. If the source uses uLowBit and uHighBit, then N equals 2 raised to the power of (uHighBit - uLowBit + 1). Otherwise, N equals 2 raised to the power of nBitsPerPixelSrc. Note that if the source is 32-bit grayscale, the value of the pPaletteSrc parameter will be ignored

uFlags supersedes nOrderSrc and nOrderDst. If you specify ORDER_BGR for nOrderSrc, but use CVT_SRCGRAY in uFlags, it will be assumed that the source buffer contains grayscale data.

Required DLLs and Libraries

Platforms

Win32, x64, Mobile.

See Also

Example

This example loads a temporary bitmap at 24 bits per pixel, creates a new 16-bit grayscale image, and uses L_ConvertBuffer to convert data from the temporary bitmap to the new one.

L_INT ConvertBufferExtExample(HWND hWnd)
{
   L_INT nRet;
   BITMAPHANDLE   LeadBitmap; /* Bitmap handle for the final image */
   BITMAPHANDLE   TmpBitmap;  /* Bitmap handle to hold the input image */
   L_UCHAR*       pBuf;       /* Buffer to hold the row */
   HGLOBAL        hBuf;       /* Handle to the buffer */
   L_INT          i;          /* Loop counter */
   /* Load the bitmap, at 24 bits per pixel */
   nRet = L_LoadBitmap (MAKE_IMAGE_PATH(TEXT("ImageProcessingDemo\\Image3.cmp")), &TmpBitmap, sizeof(BITMAPHANDLE), 24, 0, NULL, NULL);
   if(nRet != SUCCESS)
      return nRet;
   /* Create a new 16-bit grayscale bitmap */
   nRet = L_CreateBitmap(&LeadBitmap, sizeof(BITMAPHANDLE), TYPE_CONV, TmpBitmap.Width, TmpBitmap.Height,
                  16, ORDER_GRAY, NULL, TmpBitmap.ViewPerspective, NULL, 0);
   if(nRet != SUCCESS)
      return nRet;
   /* Allocate and lock the buffer */
   hBuf = GlobalAlloc(GMEM_MOVEABLE,max(LeadBitmap.BytesPerLine, TmpBitmap.BytesPerLine));
   pBuf = (L_UCHAR*)GlobalLock( hBuf );
   /* Process each row from TmpBitmap to LeadBitmap */
   L_AccessBitmap(&LeadBitmap);
   L_AccessBitmap(&TmpBitmap);
  
   for(i=0; i < TmpBitmap.Height; i++)
   {
      nRet =(L_INT) L_GetBitmapRow(&TmpBitmap, pBuf, i, TmpBitmap.BytesPerLine);
      if(nRet < 1)
         return nRet;
      nRet = L_ConvertBufferExt(pBuf, TmpBitmap.Width, 
         TmpBitmap.BitsPerPixel, LeadBitmap.BitsPerPixel,
         TmpBitmap.Order, LeadBitmap.Order, NULL, NULL,
         CVT_DSTGRAY, 0, 15);
      if(nRet != SUCCESS)
         return nRet;
      nRet = (L_INT )L_PutBitmapRow(&LeadBitmap, pBuf, i, LeadBitmap.BytesPerLine);
      if(nRet < 1)
         return nRet;
   }
   L_ReleaseBitmap(&LeadBitmap);
   L_ReleaseBitmap(&TmpBitmap);
   /* Free memory that we no longer need */
   GlobalUnlock(hBuf);
   GlobalFree(hBuf);
   nRet = L_SaveBitmap(MAKE_IMAGE_PATH(TEXT("Result.BMP")), &LeadBitmap, FILE_BMP, 24, 0, NULL);
   if(nRet != SUCCESS)
      return nRet;
   /* Free the temporary bitmap */
   if(TmpBitmap.Flags.Allocated)  
      L_FreeBitmap(&TmpBitmap);
   if(LeadBitmap.Flags.Allocated)  
      L_FreeBitmap(&LeadBitmap);
   /* Force paint palette creation */
   SendMessage (hWnd, WM_QUERYNEWPALETTE, 0, 0L);
   return SUCCESS;
}