MemDc Test

 1 VOID DrawTestInMem(HDC hDevDc)
 2 {
 3     int screenWidth = GetDeviceCaps(hDevDc, HORZRES);
 4     int screenHeight = GetDeviceCaps(hDevDc, VERTRES);
 5 
 6     HBITMAP hBmpDc = CreateCompatibleBitmap(hDevDc, screenWidth/2, screenHeight);
 7     HDC hMemDc = CreateCompatibleDC(hDevDc);
 8     SelectObject(hMemDc, hBmpDc);
 9     BitBlt(hMemDc, 0, 0, screenWidth / 2, screenHeight, hDevDc, 0, 0, SRCCOPY);
10     
11     printf("screenWidth = %d, screenHeight = %d\n", screenWidth, screenHeight);
12     WCHAR str[MAX_PATH];
13     wsprintfW(str, L"screenWidth = %d, screenHeight = %d\n", screenWidth, screenHeight);
14     TextOut(hMemDc, 0, 0, str, wcslen(str));
15     BitBlt(hDevDc, screenWidth/2+1, 0, screenWidth / 2, screenHeight, hMemDc, 0, 0, SRCCOPY);
16 
17 }
18 
19 int APIENTRY wWinMain(_In_ HINSTANCE hInstance,
20                      _In_opt_ HINSTANCE hPrevInstance,
21                      _In_ LPWSTR    lpCmdLine,
22                      _In_ int       nCmdShow)
23 {
24     UNREFERENCED_PARAMETER(hPrevInstance);
25     UNREFERENCED_PARAMETER(lpCmdLine);
26 
27     HDC hdc = GetDC(NULL);
28     
29     DrawTestInMem(hdc);
30 }