Mega Code Archive
How to make a desktop screenshot
<![CDATA[
Title: How to make a desktop screenshot
---------------------1---------------------}
function GetScreenShot: TBitmap;
var
Desktop: HDC;
begin
Result := TBitmap.Create;
Desktop := GetDC(0);
try
try
Result.PixelFormat := pf32bit;
Result.Width := Screen.Width;
Result.Height := Screen.Height;
BitBlt(Result.Canvas.Handle, 0, 0, Result.Width, Result.Height, Desktop, 0, 0, SRCCOPY);
Result.Modified := True;
finally
ReleaseDC(0, Desktop);
end;
except
Result.Free;
Result := nil;
end;
end;
procedure TForm1.Button1Click(Sender: TObject);
begin
Image1.Picture.Bitmap := GetScreenShot;
end;
{??????????????2??????????????}
procedure TForm1.Button1Click(Sender: TObject);
var DCDesk: HDC; // hDC of Desktop
bmp: TBitmap;
begin
{Create a bitmap}
bmp := TBitmap.Create;
{Set a bitmap sizes}
bmp.Height := Screen.Height;
bmp.Width := Screen.Width;
{Get a desktop DC handle - handle of a display device context}
DCDesk := GetWindowDC(GetDesktopWindow);
{Copy to any canvas, here canvas of an image}
BitBlt(bmp.Canvas.Handle, 0, 0, Screen.Width, Screen.Height,
DCDesk, 0, 0, SRCCOPY);
{Save the bitmap}
bmp.SaveToFile('ScreenShot.bmp');
{Release desktop DC handle}
ReleaseDC(GetDesktopWindow, DCDesk);
{Release a bitmap}
bmp.Free;
end;
{??????????????3??????????????}
{
If you will try to capture the screen to bitmap using BitBlt function
and have a layered (transparent) window visible,
you will get only a picture of the screen without this window.
To fix it we have to use the new raster-operation code for BitBlt
function CAPTUREBLT that introduced in Windows 2000 for including
any windows that are layered on top of your window in the resulting image.
}
procedure CaptureScreen(AFileName: string);
const
CAPTUREBLT = $40000000;
var
hdcScreen: HDC;
hdcCompatible: HDC;
bmp: TBitmap;
hbmScreen: HBITMAP;
begin
// Create a normal DC and a memory DC for the entire screen. The
// normal DC provides a "snapshot" of the screen contents. The
// memory DC keeps a copy of this "snapshot" in the associated
// bitmap.
hdcScreen := CreateDC('DISPLAY', nil, nil, nil);
hdcCompatible := CreateCompatibleDC(hdcScreen);
// Create a compatible bitmap for hdcScreen.
hbmScreen := CreateCompatibleBitmap(hdcScreen,
GetDeviceCaps(hdcScreen, HORZRES),
GetDeviceCaps(hdcScreen, VERTRES));
// Select the bitmaps into the compatible DC.
SelectObject(hdcCompatible, hbmScreen);
bmp := TBitmap.Create;
bmp.Handle := hbmScreen;
BitBlt(hdcCompatible,
0, 0,
bmp.Width, bmp.Height,
hdcScreen,
0, 0,
SRCCOPY or CAPTUREBLT);
bmp.SaveToFile(AFileName);
bmp.Free;
DeleteDC(hdcScreen);
DeleteDC(hdcCompatible);
end;
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