Двойная буферизация и WIN32 (GDI).

//
//  FUNCTION: DrawIfNeeded(HWND)
//
COLORREF color = 0;
RECT rect = {20, 20, 220, 220};
HDC hdc = 0;
HDC hdcMem = 0;
HBITMAP buffer = 0;
 
void DrawIfNeeded(HWND hWnd)
{
    ::BitBlt(hdc, rect.left, rect.top, rect.right, rect.bottom, hdcMem, rect.left, rect.top, SRCCOPY);
}
 
//
//  FUNCTION: WndProc(HWND, UINT, WPARAM, LPARAM)
//
LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    int wmId, wmEvent;
 
    switch (message)
    {
    case WM_CREATE:
        {
            hdc = ::GetDC(hWnd);
            hdcMem = ::CreateCompatibleDC(hdc);
            buffer = ::CreateCompatibleBitmap(hdc, rect.right, rect.bottom);
            ::SelectObject(hdcMem, buffer);
 
            ::SendMessageA(hWnd, WM_TIMER, NULL, NULL);
            
            ::SetTimer(hWnd, 1, 1000, NULL);
        }
        break;
    case WM_PAINT:
        {
            ::DrawIfNeeded(hWnd);
        }
        break;
    case WM_TIMER:
        {
            // create color
            color = RGB(rand()%256, rand()%256, rand()%256);
            
            // set current brush
            HBRUSH newBrush = ::CreateSolidBrush(color);
            HBRUSH oldBrush = (HBRUSH)::SelectObject(hdcMem, newBrush);
 
            // draw filled ellipse
            ::Ellipse(hdcMem, rect.left, rect.top, rect.right, rect.bottom);
 
            ::DeleteObject((HGDIOBJ)oldBrush);
            //if (CLR_INVALID == ::SetBkColor(hdcMem, color))
            //{
            //  ::MessageBoxA(hWnd, (LPCSTR)"Can't set bkgColor.", (LPCSTR)"Error", MB_OK);
            //  DestroyWindow(hWnd);
            //}
        }
        break;
    case WM_DESTROY:
        {
            ::DeleteDC(hdcMem);
            ::DeleteObject(buffer);
            ::ReleaseDC(hWnd, hdc);
            ::PostQuitMessage(0);
        }
        break;
    default:
        return DefWindowProc(hWnd, message, wParam, lParam);
    }
    return 0;
}

//
//  FUNCTION: ReDrawElipse(HWND)
//
COLORREF color = 0;
RECT rect = {20, 20, 220, 220};
HDC hdc = 0;
HDC hdcMem = 0;
HBITMAP buffer = 0;
const UINT_PTR timerPtr = 1;
 
void ReDrawElipse(HWND hWnd)
{
    COLORREF white = RGB(255, 255, 255);
    HBRUSH newBrush = ::CreateSolidBrush(white);
    HBRUSH oldBrush = (HBRUSH)::SelectObject(hdcMem, newBrush);
    ::Rectangle(hdcMem, rect.left-1, rect.top-1, rect.right+1, rect.bottom+1);
    ::DeleteObject((HGDIOBJ)oldBrush);
 
    color = RGB(rand()%256, rand()%256, rand()%256);
    newBrush = ::CreateSolidBrush(color);
    oldBrush = (HBRUSH)::SelectObject(hdcMem, newBrush);
    ::Ellipse(hdcMem, rect.left, rect.top, rect.right, rect.bottom);
    ::DeleteObject((HGDIOBJ)oldBrush);
 
    ::InvalidateRect(hWnd, &rect, false);
}
 
//
//  FUNCTION: WndProc(HWND, UINT, WPARAM, LPARAM)
//
//  PURPOSE:  Processes messages for the main window.
//
//  WM_COMMAND  - process the application menu
//  WM_PAINT    - Paint the main window
//  WM_DESTROY  - post a quit message and return
//
//
LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    int wmId, wmEvent;
    PAINTSTRUCT paintStruct;
 
    switch (message)
    {
    case WM_CREATE:
        {
            hdc = ::BeginPaint(hWnd, &paintStruct);
            hdcMem = ::CreateCompatibleDC(hdc);
            buffer = ::CreateCompatibleBitmap(hdc, rect.right, rect.bottom);
            ::SelectObject(hdcMem, buffer);
            ::EndPaint(hWnd, &paintStruct);
            
            ReDrawElipse(hWnd);
 
            ::SetTimer(hWnd, timerPtr, 1000, NULL);
        }
        break;
    case WM_COMMAND:
        wmId    = LOWORD(wParam);
        wmEvent = HIWORD(wParam);
        // Parse the menu selections:
        switch (wmId)
        {
        case IDM_EXIT:
            ::SendMessageA(hWnd, WM_DESTROY, NULL, NULL);
            break;
        default:
            return DefWindowProc(hWnd, message, wParam, lParam);
        }
        break;
    case WM_PAINT:
        {
            hdc = ::BeginPaint(hWnd, &paintStruct);
            ::BitBlt(hdc, rect.left, rect.top, rect.right, rect.bottom, hdcMem, rect.left, rect.top, SRCCOPY);
            ::EndPaint(hWnd, &paintStruct);
        }
        break;
    case WM_TIMER:
        {
            switch (wParam)
            {
            case timerPtr:
                {
                    ReDrawElipse(hWnd);
                }
                break;
            }
        }
        break;
    case WM_DESTROY:
        {
            ::DeleteObject(buffer);
            ::ReleaseDC(hWnd, hdc);
            ::PostQuitMessage(0);
        }
        break;
    default:
        return DefWindowProc(hWnd, message, wParam, lParam);
    }
    return 0;
}

::BitBlt(
hdc, 
paintStruct.rcPaint.left, 
paintStruct.rcPaint.top, 
paintStruct.rcPaint.right - paintStruct.rcPaint.left,  //Проверь, тут по-моему нужно ширину и высоту
paintStruct.rcPaint.bottom - paintStruct.rcPaint.top, //Проверь, тут по-моему нужно ширину и высоту
hdcMem, 
paintStruct.rcPaint.left, 
paintStruct.rcPaint.top, 
SRCCOPY);

        COLORREF white = RGB(255, 255, 255);
        HBRUSH newBrush = ::CreateSolidBrush(white);
        HBRUSH oldBrush = (HBRUSH)::SelectObject(hdcMem, newBrush);
        ::Rectangle(hdcMem, rect.left-1, rect.top-1, rect.right+1, rect.bottom+1);
        ::DeleteObject((HGDIOBJ)oldBrush);

bool getIntersection(RECT rect1, RECT rect2, RECT *result)
{
    result->left = max(rect1.left, rect2.left);
    result->right = min(rect1.right, rect2.right);
    result->top = max(rect1.top, rect2.top);
    result->bottom = min(rect1.bottom, rect2.bottom);
 
    return res->left <= res->right && res->top <= res->bottom;
}
 
//  FUNCTION: WndProc(HWND, UINT, WPARAM, LPARAM)
 
    case WM_PAINT:
        {
            hdc = ::BeginPaint(hWnd, &paintStruct);
            RECT rc;
            // rect - поле, которое перерисовывает этот блок
            if (getIntersection(paintStruct.rcPaint, rect, &rc)) 
            {
                ::BitBlt(hdc, rc.left, rc.top, rc.right - rc.left, rc.bottom - rc.top, hdcMem, rc.left, rc.top, SRCCOPY);
            }
            ::EndPaint(hWnd, &paintStruct);
        }
        break;