保存打印机dc到bmp文件,全黑色没数据?前辈们来帮忙啦(有码)

qqwweerraahh 2013-03-13 11:19:34
对gdi不熟,前辈们帮帮忙,拖了好几天了,前辈们帮帮忙
试了下面两个函数,传入窗口dc可以正常用,但是传入某个打印机dc时得到的bmp文件是全黑的没有数据

获取dc位图

HBITMAP GetSrcBit(HDC hDC,DWORD BitWidth, DWORD BitHeight)
{
HDC hBufDC;
HBITMAP hBitmap, hBitTemp;

hBufDC = CreateCompatibleDC(hDC);

hBitmap = CreateCompatibleBitmap(hDC, BitWidth, BitHeight);
hBitTemp = (HBITMAP) SelectObject(hBufDC, hBitmap);

StretchBlt(hBufDC, 0, 0, BitWidth, BitHeight,
hDC, 0, 0, BitWidth, BitHeight, SRCCOPY);

hBitmap = (HBITMAP) SelectObject(hBufDC, hBitTemp);

DeleteObject(hBitTemp);
::DeleteDC(hBufDC);
return hBitmap;
}


保存位图到文件

BOOL SaveBmp(HBITMAP hBitmap, CString FileName)
{
HDC hDC;

int iBits;

WORD wBitCount;

DWORD dwPaletteSize=0, dwBmBitsSize=0, dwDIBSize=0, dwWritten=0;

BITMAP Bitmap;

BITMAPFILEHEADER bmfHdr;

BITMAPINFOHEADER bi;

LPBITMAPINFOHEADER lpbi;

HANDLE fh, hDib, hPal,hOldPal=NULL;

hDC = CreateDC("DISPLAY", NULL, NULL, NULL);
iBits = GetDeviceCaps(hDC, BITSPIXEL) * GetDeviceCaps(hDC, PLANES);
DeleteDC(hDC);
if (iBits <= 1) wBitCount = 1;
else if (iBits <= 4) wBitCount = 4;
else if (iBits <= 8) wBitCount = 8;
else wBitCount = 24;
GetObject(hBitmap, sizeof(Bitmap), (LPSTR)&Bitmap);
bi.biSize = sizeof(BITMAPINFOHEADER);
bi.biWidth = Bitmap.bmWidth;
bi.biHeight = Bitmap.bmHeight;
bi.biPlanes = 1;
bi.biBitCount = wBitCount;
bi.biCompression = BI_RGB;
bi.biSizeImage = 0;
bi.biXPelsPerMeter = 0;
bi.biYPelsPerMeter = 0;
bi.biClrImportant = 0;
bi.biClrUsed = 0;
dwBmBitsSize = ((Bitmap.bmWidth * wBitCount + 31) / 32) * 4 * Bitmap.bmHeight;

hDib = GlobalAlloc(GHND,dwBmBitsSize + dwPaletteSize + sizeof(BITMAPINFOHEADER));
lpbi = (LPBITMAPINFOHEADER)GlobalLock(hDib);
*lpbi = bi;

hPal = GetStockObject(DEFAULT_PALETTE);
if (hPal)
{
hDC = ::GetDC(NULL);
hOldPal = ::SelectPalette(hDC, (HPALETTE)hPal, FALSE);
RealizePalette(hDC);
}

GetDIBits(hDC, hBitmap, 0, (UINT) Bitmap.bmHeight, (LPSTR)lpbi + sizeof(BITMAPINFOHEADER) +dwPaletteSize, (BITMAPINFO *)lpbi, DIB_RGB_COLORS);

if (hOldPal)
{
::SelectPalette(hDC, (HPALETTE)hOldPal, TRUE);
RealizePalette(hDC);
::ReleaseDC(NULL, hDC);
}

fh = CreateFile(FileName, GENERIC_WRITE,0, NULL, CREATE_ALWAYS,
FILE_ATTRIBUTE_NORMAL | FILE_FLAG_SEQUENTIAL_SCAN, NULL);
if (fh == INVALID_HANDLE_VALUE) return FALSE;

bmfHdr.bfType = 0x4D42; // "BM"
dwDIBSize = sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER) + dwPaletteSize + dwBmBitsSize;
bmfHdr.bfSize = dwDIBSize;
bmfHdr.bfReserved1 = 0;
bmfHdr.bfReserved2 = 0;
bmfHdr.bfOffBits = (DWORD)sizeof(BITMAPFILEHEADER) + (DWORD)sizeof(BITMAPINFOHEADER) + dwPaletteSize;

WriteFile(fh, (LPSTR)&bmfHdr, sizeof(BITMAPFILEHEADER), &dwWritten, NULL);

WriteFile(fh, (LPSTR)lpbi, dwDIBSize, &dwWritten, NULL);

GlobalUnlock(hDib);
GlobalFree(hDib);
CloseHandle(fh);

return TRUE;
}
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qqwweerraahh 2013-03-13
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我是做了一个hook,在EndPage时劫到的dc

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