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ben · Guest

How can I save the content of the given HDC to a ".bmp" file?? (Only use the
Win API)

Lord Crc · Guest

On Wed, 4 Oct 2006 20:34:49 +0800, "ben" <wtu_ben (AT) 163 (DOT) com> wrote:

Peter Below (TeamB) · Guest

ben wrote:

ben · Guest

The following is my code,but I find it not working properly(cannot save to
the "bmp" file!)
What's wrong? thx~

unit u_SaveClientToBmp;

interface

uses
Windows,
Messages,
Graphics,
SysUtils;

function SaveClientToFile(WinHD: HWND; Width, Height: Integer; szFName:
PChar): Integer;

implementation

function SaveClientToFile(WinHD: HWND; Width, Height: Integer; szFName:
PChar): Integer;
var
WinDC, hMemDC: HDC;
hBits, hFile: THandle;
winBitmap, hTmpBmp: HBITMAP;
hPal: HPALETTE;
lpBits: Pointer;
aRGBQuad: RGBQUAD;
ImgSize, plSize, dwWritten: DWORD;
i, CRes: Integer;
bmFH: BITMAPFILEHEADER;
pBmInfo, pBmInfoMem: PBitmapInfo;
lp: PLogPalette;
testBMP: TBitmap;
begin
hFile := CreateFile(szFName, GENERIC_WRITE, 0, nil, CREATE_ALWAYS,
FILE_ATTRIBUTE_NORMAL, 0);
if hFile = 0 then Result := 1;
//createfile

WinHD := GetForegroundWindow;
WinDC := GetDC(WinHD);
winBitmap := CreateCompatibleBitmap(WinDC, Width, Height);
// hTmpBmp := CreateCompatibleBitmap(WinDC, Width, Height);
pBmInfoMem := PBitmapInfo(GlobalAlloc(GHND, sizeof(BITMAPINFO) + 256 *
sizeof(RGBQUAD)));
pBmInfo := PBitmapInfo(GlobalLock(GlobalAlloc(GHND, sizeof(BITMAPINFO) +
256 * sizeof(RGBQUAD))));
//pBmInfo := GlobalLock(pBmInfoMem);
hTmpBmp:=SelectObject(hMemDC, winBitmap);
BitBlt(hMemDC, 0, 0, Width, Height, WinDC, 0, 0, SRCCOPY);
SelectObject(hMemDC, hTmpBmp);
testBMP := TBitmap.Create;
testBMP.Width := Width;
testBMP.Height := Height;
Windows.BitBlt(testBMP.Canvas.Handle, 0, 0, hMemDC, Height, WinDC, 0, 0,
SRCCOPY);
testBMP.SaveToFile('D:\test.bmp');
testBMP.Free;

ZeroMemory(pBmInfo, sizeof(BITMAPINFO));
with pBmInfo^.bmiHeader do
begin
biSize := DWORD(sizeof(BITMAPINFOHEADER));
biWidth := Width;
biHeight := Height;
biPlanes := 1;
biBitCount := WORD(GetDeviceCaps(WinDC, BITSPIXEL));
biCompression := BI_RGB;
GetDIBits(WinDC, winBitmap, 0, Height, nil, pBmInfo^, DIB_RGB_COLORS);
if biSizeImage = 0 then
biSizeImage := Round((((biWidth * biBitCount) + 31) / 32)) * 4 *
biHeight;
//biSizeImage = ((((biWidth * biBitCount) + 31) and ~31) / Cool

*
biHeight;
CRes := GetDeviceCaps(WinDC, SIZEPALETTE);
plSize := CRes * sizeof(RGBQUAD);
ImgSize := biSizeImage;
end;

bmFH.bfType := $4D42; //"BM"
bmFH.bfOffBits := plSize + sizeof(BITMAPINFOHEADER) +
sizeof(BITMAPFILEHEADER);
bmFH.bfSize := ImgSize + bmFH.bfOffBits;
bmFH.bfReserved1 := 0;
bmFH.bfReserved2 := 0;

WriteFile(hFile, bmFH, sizeof(BITMAPFILEHEADER), dwWritten, nil);
WriteFile(hFile, pBmInfo^.bmiHeader, sizeof(BITMAPINFOHEADER), dwWritten,
nil);

if (CRes <> 0) then
begin
hPal := HPALETTE(GlobalAlloc(GHND, sizeof(LOGPALETTE) + (CRes *
sizeof(PALETTEENTRY))));
lp := GlobalLock(hPal);
lp^.palNumEntries := WORD(CRes);
lp^.palVersion := $0300;
GetSystemPaletteEntries(WinDC, 0, CRes, lp^.palPalEntry);
aRGBQuad.rgbReserved := 0;
for i := 0 to CRes do
begin
aRGBQuad.rgbRed := lp^.palPalEntry[i].peRed;
aRGBQuad.rgbGreen := lp^.palPalEntry[i].peGreen;
aRGBQuad.rgbBlue := lp^.palPalEntry[i].peBlue;
WriteFile(hFile, aRGBQuad, sizeof(RGBQUAD), dwWritten, nil);
end;
GlobalUnlock(hPal);
GlobalFree(hPal);
end;

hBits := GlobalAlloc(GHND, pBmInfo^.bmiHeader.biSizeImage);
lpBits := GlobalLock(hBits);
GetDIBits(WinDC, winBitmap, 0, Height, lpBits, pBmInfo^, DIB_RGB_COLORS);
WriteFile(hFile, lpBits, ImgSize, dwWritten, nil);
GlobalUnlock(hBits);
GlobalFree(hBits);

GlobalUnlock(Integer(pBmInfo));
GlobalFree(Integer(pBmInfoMem));
DeleteObject(hTmpBmp);
DeleteObject(winBITMAP);
DeleteDC(hMemDC);
ReleaseDC(WinHD, WinDC);
CloseHandle(hFile);
//SetCursor(LoadCursor(NULL, IDC_ARROW));

Result := 0;
end;

end.