关于DDB到DIB

[cwdazy]

我怎样才能把一个DDB位图转化成为DIB位图？谢谢，DDB位图使用起来总觉得碍手碍脚

[bluebohe]

// DDBToDIB - Creates a DIB from a DDB
// bitmap - Device dependent bitmap
// dwCompression - Type of compression - see BITMAPINFOHEADER
// pPal - Logical palette
HANDLE DDBToDIB( CBitmap& bitmap, DWORD dwCompression, CPalette* pPal )
{
BITMAP bm;
BITMAPINFOHEADER bi;
LPBITMAPINFOHEADER lpbi;
DWORD dwLen;
HANDLE hDIB;
HANDLE handle;
HDC hDC;
HPALETTE hPal;


ASSERT( bitmap.GetSafeHandle() );

// The function has no arg for bitfields
if( dwCompression == BI_BITFIELDS )
return NULL;

// If a palette has not been supplied use defaul palette
hPal = (HPALETTE) pPal->GetSafeHandle();
if (hPal==NULL)
hPal = (HPALETTE) GetStockObject(DEFAULT_PALETTE);

// Get bitmap information
bitmap.GetObject(sizeof(bm),(LPSTR)&bm);

// Initialize the bitmapinfoheader
bi.biSize = sizeof(BITMAPINFOHEADER);
bi.biWidth = bm.bmWidth;
bi.biHeight = bm.bmHeight;
bi.biPlanes = 1;
bi.biBitCount = bm.bmPlanes * bm.bmBitsPixel;
bi.biCompression = dwCompression;
bi.biSizeImage = 0;
bi.biXPelsPerMeter = 0;
bi.biYPelsPerMeter = 0;
bi.biClrUsed = 0;
bi.biClrImportant = 0;

// Compute the size of the infoheader and the color table
int nColors = (1 << bi.biBitCount);
if( nColors > 256 )
nColors = 0;
dwLen = bi.biSize + nColors * sizeof(RGBQUAD);

// We need a device context to get the DIB from
hDC = GetDC(NULL);
hPal = SelectPalette(hDC,hPal,FALSE);
RealizePalette(hDC);

// Allocate enough memory to hold bitmapinfoheader and color table
hDIB = GlobalAlloc(GMEM_FIXED,dwLen);

if (!hDIB){
SelectPalette(hDC,hPal,FALSE);
ReleaseDC(NULL,hDC);
return NULL;
}

lpbi = (LPBITMAPINFOHEADER)hDIB;

*lpbi = bi;

// Call GetDIBits with a NULL lpBits param, so the device driver
// will calculate the biSizeImage field
GetDIBits(hDC, (HBITMAP)bitmap.GetSafeHandle(), 0L, (DWORD)bi.biHeight,
(LPBYTE)NULL, (LPBITMAPINFO)lpbi, (DWORD)DIB_RGB_COLORS);

bi = *lpbi;

// If the driver did not fill in the biSizeImage field, then compute it
// Each scan line of the image is aligned on a DWORD (32bit) boundary
if (bi.biSizeImage == 0){
bi.biSizeImage = ((((bi.biWidth * bi.biBitCount) + 31) & ~31) / 8)
* bi.biHeight;

// If a compression scheme is used the result may infact be larger
// Increase the size to account for this.
if (dwCompression != BI_RGB)
bi.biSizeImage = (bi.biSizeImage * 3) / 2;
}

// Realloc the buffer so that it can hold all the bits
dwLen += bi.biSizeImage;
if (handle = GlobalReAlloc(hDIB, dwLen, GMEM_MOVEABLE))
hDIB = handle;
else{
GlobalFree(hDIB);

// Reselect the original palette
SelectPalette(hDC,hPal,FALSE);
ReleaseDC(NULL,hDC);
return NULL;
}

// Get the bitmap bits
lpbi = (LPBITMAPINFOHEADER)hDIB;

// FINALLY get the DIB
BOOL bGotBits = GetDIBits( hDC, (HBITMAP)bitmap.GetSafeHandle(),
0L, // Start scan line
(DWORD)bi.biHeight, // # of scan lines
(LPBYTE)lpbi // address for bitmap bits
+ (bi.biSize + nColors * sizeof(RGBQUAD)),
(LPBITMAPINFO)lpbi, // address of bitmapinfo
(DWORD)DIB_RGB_COLORS); // Use RGB for color table





if( !bGotBits )
{
GlobalFree(hDIB);

SelectPalette(hDC,hPal,FALSE);
ReleaseDC(NULL,hDC);
return NULL;
}

SelectPalette(hDC,hPal,FALSE);
ReleaseDC(NULL,hDC);
return hDIB;
}

[cwdazy]

大哥，最后的参数怎么用？

[bluebohe]

HPALETTE hPal;
if(GetDeviceCaps(hDC,RASTERCAPS) & RC_PALETTE )
{
UINT nSize = sizeof(LOGPALETTE) + (sizeof(PALETTEENTRY) * 256);
LOGPALETTE *pLP = (LOGPALETTE *) new BYTE[nSize];
pLP->palVersion = 0x300;
pLP->palNumEntries =GetSystemPaletteEntries( hDC, 0, 255, pLP->palPalEntry );
hPal=CreatePalette(pLP );
delete[] pLP;
}
然后映射到CPalette上