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LBitmapBase::SetDataPointer

Summary

Sets the data pointer for the bitmap to the specified data pointer pData.

Syntax

#include "ltwrappr.h"

virtual L_INT LBitmapBase::SetDataPointer(pData, dwSize)

Parameters

L_UCHAR *pData

Data pointer used to set the bitmaps data pointer.

L_UINT32 dwSize

Size of the data buffer pointed to by pData.

Returns

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

Comments

This function can be used to change the data pointer of a bitmap that was created by LBitmapBase::CreateBitmap, or allocated by LBitmapBase::Allocate, with memory type TYPE_USER. The data pointer to of the bitmap is set to the data pointer passed in through pData.

You are responsible for managing the image data. LBitmapBase::Free will not free pData.

The memory buffer pointed to by pData must be valid when the bitmap is being used. If you free a memory buffer that is referenced by a bitmap, you will get access violations when you try to use that bitmap.

If you pass NULL for pData, the bitmap has no bitmap data. You should not try to use a bitmap that has no data pointer.

NOTE: To calculate the correct size for a single row of image data:

(((Width * BitsPerPixel) + 31) >> 3)) &~3

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.

Example

#define BITMAP_WIDTH 256 
#define BITMAP_HEIGHT 256 
 
L_INT LBitmapBase__SetDataPointerExample(HWND hWnd) 
{ 
   UNREFERENCED_PARAMETER(hWnd); 
 
   L_INT nRet; 
   HGLOBAL hGlobal1, hGlobal2; 
   L_UCHAR *pBuffer1, *pBuffer2; 
   LBitmapBase BitmapBase;  
   //pBuffer1 points to raw data with 256 shades of red 
   //pBuffer2 points to raw data with 256 shades of green 
   hGlobal1 = GlobalAlloc(GMEM_MOVEABLE, BITMAP_WIDTH * BITMAP_HEIGHT * 3); 
   pBuffer1 = (L_UCHAR*)GlobalLock(hGlobal1);  
   hGlobal2 = GlobalAlloc(GMEM_MOVEABLE, BITMAP_WIDTH * BITMAP_HEIGHT * 3); 
   pBuffer2 = (L_UCHAR*)GlobalLock(hGlobal2);  
   L_INT iCol, iRow, iCounter;  
   iCounter = 0; 
   for(iCol = 0; iCol < BITMAP_WIDTH; iCol++) 
      for (iRow=0; iRow < BITMAP_HEIGHT; iRow++) 
      { 
         pBuffer1[iCounter + 0] = 0; //Blue 
         pBuffer1[iCounter + 1] = 0; //Green 
         pBuffer1[iCounter + 2] = (L_UCHAR)iCol; //Red  
         pBuffer2[iCounter + 0] = 0; //Blue 
         pBuffer2[iCounter + 1] = (L_UCHAR) iCol; //Green 
         pBuffer2[iCounter + 2] = 0; //Red  
         iCounter = iCounter + 3; 
      } 
      // this sets the image to be pBuffer1 
      nRet =BitmapBase.Create(  
            BITMAP_WIDTH,  
            BITMAP_HEIGHT,  
            24,  
            ORDER_BGR,  
            NULL,  
            TOP_LEFT,  
            TYPE_USER, 
            (L_UCHAR *)pBuffer1,  
            BITMAP_WIDTH * BITMAP_HEIGHT * 3); 
      if(nRet !=SUCCESS) 
         return nRet; 
 
   nRet =BitmapBase.Save(MAKE_IMAGE_PATH(TEXT("Test1.bmp")), FILE_BMP, 24,2,0,NULL); 
   if(nRet !=SUCCESS) 
      return nRet; 
   nRet =BitmapBase.SetDataPointer(pBuffer2, BITMAP_WIDTH * BITMAP_HEIGHT * 3); 
   if(nRet !=SUCCESS) 
      return nRet; 
   nRet =BitmapBase.Save(MAKE_IMAGE_PATH(TEXT("Test2.bmp")), FILE_BMP, 24,2,0,NULL); 
   if(nRet !=SUCCESS) 
      return nRet; 
 
   return SUCCESS; 
}