L_SetBitmapDataPointer
#include "l_bitmap.h"
L_INT EXT_FUNCTION L_SetBitmapDataPointer(pBitmap, pData, dwSize)
pBITMAPHANDLE pBitmap; |
/* pointer to the bitmap handle */ |
/* data pointer */ | |
L_UINT32 dwSize; |
/* size of the data buffer pointed to by pData */ |
Sets the data pointer for the specified bitmap to the specified data pointer pData.
Parameter |
Description |
pBitmap |
Pointer to the bitmap handle that references the bitmap whose data pointer will be set. |
pData |
Data pointer used to set the specified bitmap’s data pointer. |
dwSize |
Size of the data buffer pointed to by pData. |
Returns
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 L_CreateBitmap, or allocated by L_AllocateBitmap, 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. L_FreeBitmap 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.
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
Windows 95 / 98 / Me, Windows 2000 / XP, Windows CE.
See Also
Functions: |
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Topics: |
Example
Please note that you need to free the memory allocated for the bitmap and the bitmap data using the following:
L_FreeBitmap(pBitmap);
GlobalFreePtr(pBuffer);
#include "windowsx.h"
L_INT TestDataPointer(pBITMAPHANDLE pBitmap)
{
// allocate a buffer large enough to hold two copies of the image
L_UCHAR L_HUGE*pBuffer = (L_UCHAR L_FAR *)GlobalAllocPtr(GMEM_MOVEABLE, pBitmap->Size * 2);
L_INT i;
L_INT nRet;
// loop and get the flipped and normal versions of the image into pBuffer
for(i = 0; i < pBitmap->Height; i++)
{
L_GetBitmapRow(pBitmap,
pBuffer + i * pBitmap->BytesPerLine,
pBitmap->ViewPerspective == TOP_LEFT ? pBitmap->Height - i - 1 : i,
pBitmap->BytesPerLine);
memcpy( pBuffer + pBitmap->Size + (pBitmap->Height - i - 1) * pBitmap->BytesPerLine,
pBuffer + i * pBitmap->BytesPerLine,
pBitmap->BytesPerLine);
}
// free the original image. Note that it is assumed that the image was 24 bit
// for simplicity, so that it is not necessary to pass an array of palette entries to L_CreateBitmap
// For color images, you would have to get the palette entries and pass them instead of NULL
L_FreeBitmap(pBitmap);
// this sets the image to be the flipped version
if((nRet = L_CreateBitmap(pBitmap, sizeof(BITMAPHANDLE),
TYPE_USER,
pBitmap->Width, pBitmap->Height, pBitmap->BitsPerPixel,
pBitmap->Order, NULL,
TOP_LEFT,
pBuffer, pBitmap->Size)) == SUCCESS)
{
MessageBox( NULL, TEXT("The image is flipped"), TEXT(""), MB_OK);
// this sets the image to be the non-flipped version
return L_SetBitmapDataPointer(pBitmap, pBuffer + pBitmap->Size, pBitmap->Size);
}
return nRet;
}