[FIXED] SetWindowRgn freezes window

Issue

As the title says, I am having a problem with the window of an application freezing (not painting anymore) after I call SetWindowRgn. My source code is as follows:

    void MakeHole() 
    {
      // This will make a hole you can see through for the MainToon window.
      HRGN thisHgrn = CreateRectRgn(10, 200, 300, 200);
      SetWindowRgn(hwndClientList[intMainToon], thisHgrn, TRUE);
    }

I’m not even quite sure SetWindowRgn is the code I need to use. All I want to accomplish is a hole (transparent block) in a game window so that I can see through it. None of the other code in the project is really relevant at this point. Everything works as intended except that after I call SetWindowRgn, the game window doesn’t draw anymore. It looks frozen but I can still close the window and the sound is still playing clearly. This is a visual C++ console application but I don’t see how that could be of any importance either.
Let me know if you need anymore information.

Thanks for any help.

Solution

Fixed the problem with the following code.

    void MakeHole()
    {
       // This will make a hole you can see through for the MainToon window.

       HRGN rgnOriginalWnd;
       HRGN rgnTheHole;
       HRGN rgnNewWnd;

       RECT rectDlg;
       GetWindowRect(hwndClientList[intMainToon], &rectDlg);

       rgnOriginalWnd = CreateRectRgn(0, 0, rectDlg.right - rectDlg.left, rectDlg.bottom - rectDlg.top);
       rgnTheHole = CreateRectRgn(10, 200, 350, 450);
       rgnNewWnd = CreateRectRgn(0, 0, 0, 0);

       CombineRgn(rgnNewWnd, rgnOriginalWnd, rgnTheHole, RGN_DIFF);
       SetWindowRgn(hwndClientList[intMainToon], rgnNewWnd, TRUE);

       DeleteObject(rgnOriginalWnd);
       DeleteObject(rgnTheHole);
       DeleteObject(rgnNewWnd);
    }

Answered By – Levi Roberts

Answer Checked By – Pedro (FixeMe Volunteer)