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.

Parameters

L_UCHAR *pBuffer

Pointer to the input buffer.

L_INT nWidth

Image width, in pixels.

L_INT nBitsPerPixelSrc

Input bits per pixel. Possible values are 1, 2, 3, 4, 5, 6, 7, 8, 16, 24, 32, 48, and 64.

L_INT nBitsPerPixelDst

Output bits per pixel. Use 0 for 8-bit grayscale.

L_INT nOrderSrc

The input color order. Possible values are:

L_INT nOrderDst

The output color order. Possible values are:

L_RGBQUAD* pPaletteSrc

Pointer to the palette for the existing data, before conversion. If the data is converted from 16 or 24 bits per pixel, use NULL for no palette.

L_RGBQUAD* pPaletteDst

Pointer to the palette for the converted data. If the data is converted to 16 or 24 bits per pixel color, use NULL for no palette.

L_UINT uFlags

Flags indicating whether to treat 16 bit data as grayscale or color. Possible values are:

L_INT uLowBit

Value indicating the low bit in the source buffer, if the source buffer contains grayscale data.

L_INT uHighBit

Value indicating the high bit in the source buffer, if the source buffer contains grayscale data.

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

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

Platforms

Win32, x64, Linux.

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; 
}