Thread: BitBlt

Hi
This time I am trying to develop some little app. which is able to work a little with images mainly BMP format.

Code:

HDC hDC;
HDC hOffScreenDC;
PAINTSTRUCT ps;
(object _pPic;)

InvalidateRect(hWnd, NULL, TRUE);
hDC = BeginPaint(hWnd, &ps);
_pPic->Draw(hOffScreenDC);
BitBlt(hDC, 0, 0, 640, 480, hOffScreenDC, 0, 0, SRCCOPY);
EndPaint(hWnd, &ps);
ReleaseDC(hWnd, hDC);

I would like to avoid the annoying flashing the client rect while it is being redrawn when I for eg. move a bitmap.

I saw a programme which used the BitBlt() and it worked without any problem... Mine code does not work, can you tell me why? The code is not correct is it?

So I modified a bit my previous code and it started to work...

Code:

hOffScreenDC = CreateCompatibleDC(GetDC(hWnd));
hOffScreenBitmap = CreateCompatibleBitmap(GetDC(hWnd), x, y);
SelectObject(hOffScreenDC, hOffScreenBitmap);
HDC hDC = GetDC(hWnd);
BitBlt(hDC, 0, 0, x y, hOffScreenDC, 0, 0, SRCCOPY);

Of course this code does not come from only one function but the base of the redrawing is hidden in this code...

Even thou thx for help