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分享获得了HBITMAP，如何获得BITMAPINFOHEADER以及位图文件的数据区？
获得了HBITMAP，如何获得BITMAPINFOHEADER以及位图文件的数据区？
用来填写函数StretchDIBits？
用来填写函数StretchDIBits？
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qqhuangshen 2004-07-25
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如果仅仅想使用StretchDIBBits函数，这里给你提供一段代码：
CBitmap m_Bitmap;
m_Bitmap.Attach(hBitmap);
CDC MemDC;
CBitmap *oldBmp;
BITMAP bmpInfo;
int bmWidth,bmHeight;
MemDC.CreateCompatibleDC(pDC);
oldBmp=MemDC.SelectObject(&m_Bitmap);
m_Bitmap.GetBitmap(&bmpInfo); //获取位图的尺寸
bmWidth=bmpInfo.bmWidth;
bmHeight=bmpInfo.bmHeight;
CRect rect;
pDC->GetClientRect(&rect);
pDC->StrechBlt(0,0,bmWidth,bmHeight,&MemDC,0,0,rect.Width,rect.Height,SRCCOPY);
MemDC.SelectObject(oldBmp); //使位图m_Bitmap脱离设备上下文
CBitmap m_Bitmap;
m_Bitmap.Attach(hBitmap);
CDC MemDC;
CBitmap *oldBmp;
BITMAP bmpInfo;
int bmWidth,bmHeight;
MemDC.CreateCompatibleDC(pDC);
oldBmp=MemDC.SelectObject(&m_Bitmap);
m_Bitmap.GetBitmap(&bmpInfo); //获取位图的尺寸
bmWidth=bmpInfo.bmWidth;
bmHeight=bmpInfo.bmHeight;
CRect rect;
pDC->GetClientRect(&rect);
pDC->StrechBlt(0,0,bmWidth,bmHeight,&MemDC,0,0,rect.Width,rect.Height,SRCCOPY);
MemDC.SelectObject(oldBmp); //使位图m_Bitmap脱离设备上下文
qqhuangshen 2004-07-25
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先用CBitmap 里的attach函数将HBITMAP选入类中。然后，这里给你提供一个函数
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;
}
调用系统提供的一些DIB函数就可以获得这些信息（其实，在这个函数过程中。通过锁定句柄已经获得了BITMAPINFOHEADER结构，而通过BOOL bGotBits = GetDIBits( hDC, (HBITMAP)bitmap.GetSafeHandle(),0L,(DWORD)bi.biHeight,(LPBYTE)lpbi+ (bi.biSize + nColors * sizeof(RGBQUAD)), (LPBITMAPINFO)lpbi,(DWORD)DIB_RGB_COLORS)获得了图像的象素信息)
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;
}
调用系统提供的一些DIB函数就可以获得这些信息（其实，在这个函数过程中。通过锁定句柄已经获得了BITMAPINFOHEADER结构，而通过BOOL bGotBits = GetDIBits( hDC, (HBITMAP)bitmap.GetSafeHandle(),0L,(DWORD)bi.biHeight,(LPBYTE)lpbi+ (bi.biSize + nColors * sizeof(RGBQUAD)), (LPBITMAPINFO)lpbi,(DWORD)DIB_RGB_COLORS)获得了图像的象素信息)
名牌大灰狼 2004-07-25
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详细教程http://www-scf.usc.edu/~flv/ipbook/chap01.htm
