Отображение и масштабирование картинки в окне программы

#include <windows.h>
 
/*  Declare Windows procedure  */
LRESULT CALLBACK DCDemoWndProc (HWND, UINT, UINT, LONG);
 
/*  WINAPI - îïðåäåëÿåò ïîðÿäîê ïåðåäà÷è ïàðàìåòðîâ ïðè âûçîâå ïðîöåäóðû  */
int WINAPI WinMain (HINSTANCE hThisInstance, //Õýíäë ýêçåìïëÿðà ïðîãðàììû
                    HINSTANCE hPrevInstance, //Æýíäë ïðåäûäóùåãî ýêçåìïëÿðà ïðîãðàììû
                    LPSTR lpszCmdParam,
                    int nCmdShow) //Âèä îêíà
 
{
    HWND hWnd;               /* This is the handle for our window */
    MSG Msg;            /* Here messages to the application are saved */
    WNDCLASS WndClass;        /* Data structure for the windowclass */
    char szClassName[ ] = "DCDemo";
 
    /* The Window structure */
    WndClass.style = CS_HREDRAW | CS_VREDRAW;      /* Ïåðåðèñîâêà îêíà ïðè èçìåíåíèè âûñîòû è øèðèíû îêíà */
    WndClass.lpfnWndProc = DCDemoWndProc;      /* This function is called by windows */
    WndClass.cbClsExtra = 0;                      /* No extra bytes after the window class */
    WndClass.cbWndExtra = 0;                      /* structure or the window instance */
    WndClass.hInstance = hThisInstance;
    WndClass.hIcon = LoadIcon (NULL, IDI_APPLICATION);
    WndClass.hCursor = LoadCursor (NULL, IDC_ARROW);
    WndClass.hbrBackground = (HBRUSH) GetStockObject(WHITE_BRUSH);
    WndClass.lpszMenuName = "MyMenu";                 /* No menu */
    WndClass.lpszClassName = szClassName;
 
    /* Use default icon and mouse-pointer */
    /* Use Windows's default color as the background of the window */
 
    /* Register the window class, and if it fails quit the program */
    if (!RegisterClass(&WndClass))
    {
        MessageBox(NULL, "Cannot register class", "Error", MB_OK);
        return 0;
    }
    /* The class is registered, let's create the program*/
    hWnd = CreateWindow (
           szClassName,         /* Classname */
           "Programm 1",       /* Title Text */
           WS_OVERLAPPEDWINDOW, /* default window */
           CW_USEDEFAULT,       /* Windows decides the position */
           CW_USEDEFAULT,       /* where the window ends up on the screen */
           CW_USEDEFAULT,
           CW_USEDEFAULT,
           NULL,        /* The window is a child-window to desktop */
           NULL,                /* No menu */
           hThisInstance,       /* Program Instance handler */
           NULL                 /* No Window Creation data */
           );
    
    if (!hWnd)
    {
        MessageBox(NULL, "Cannot create window", "Error", MB_OK);
        return 0;
    }
    
    /* Make the window visible on the screen */
    ShowWindow (hWnd, nCmdShow);
    UpdateWindow(hWnd);
    /* Run the message loop. It will run until GetMessage() returns 0 */
    while (GetMessage(&Msg, NULL, 0, 0))
    {
        /* Translate virtual-key messages into character messages */
        TranslateMessage(&Msg);
        /* Send message to WindowProcedure */
        DispatchMessage(&Msg);
    }
 
    /* The program return-value is 0 - The value that PostQuitMessage() gave */
    return Msg.wParam;
}
 
 
/*  This function is called by the Windows function DispatchMessage()  */
 
LRESULT CALLBACK DCDemoWndProc(HWND hWnd, UINT Message, UINT wParam, LONG lParam)
{
    HDC hDC, hCompatibleDC;
    PAINTSTRUCT PaintStruct;
    HANDLE hBitmap, hOldBitmap;
    RECT Rect;
    BITMAP Bitmap;
    switch (Message)                  /* handle the messages */
    {
        case WM_PAINT:
            //Ïîëó÷àåì êîíòåêñò óñòðîéñòâà.
            hDC = BeginPaint(hWnd,&PaintStruct);
            //Çàãðóæàåì bitmap, êîòîðûé áóäåò îòîáðàæàòüñÿ â îêíåá èç ôàéëà.
            hBitmap = LoadImage(NULL, "SOUNDMAX.BMP",
            IMAGE_BITMAP,
            0, 0,
            LR_LOADFROMFILE);
            //Ïîëó÷àåì ðàçìåðíîñòü çàãðóæåííîãî bitmap'a.
            GetObject(hBitmap, sizeof(BITMAP), &Bitmap);
            //Ñîçäà¸ì ñîâìåñòèìûé ñ êîíòåêñòîì îêíà êîíòåêñò â ïàìÿòè.
            hCompatibleDC = CreateCompatibleDC(hDC);
            //Äåëàåì çàãðóæåííûé èç ôàéëà bitmap òåêóùèì â ñîâìåñòèìîì êîíòåêñòå.
            hOldBitmap = SelectObject(hCompatibleDC, hBitmap);
            //Îïðåäåëÿåì ðàçìåð ðàáî÷åé îáëàñòè îêà.
            GetClientRect(hWnd,&Rect);
            //Êîïèðóåì bitmap ñ ñîâìåñòèìîãî íà îñíîâíîé êîíòåêñò ñ ìàñøòàáèðîâàíèåì.
            StretchBlt(hDC, 0, 0, Rect.right, Rect.bottom,
            hCompatibleDC, 0, 0,  Bitmap.bmWidth,
            Bitmap.bmHeight, SRCCOPY);
            //Âíîâü äåëàåì ñòàðûé bitmap òåêóùèì.
            SelectObject(hCompatibleDC, hOldBitmap);
            //Óäàëÿåì çàãðóæåííûé ñ äèñêà bitmap.
            DeleteObject(hBitmap);
            //Óäàëÿåì ñîâìåñòèìûé êîíòåêñò/
            DeleteDC(hCompatibleDC);
            EndPaint(hWnd,&PaintStruct);
            return 0;
        case WM_DESTROY:
            PostQuitMessage (0);       /* send a WM_QUIT to the message queue */
            return 0;
    }
 
    return DefWindowProc (hWnd, Message, wParam, lParam);
}

hBitmap = LoadImage(NULL, "SOUNDMAX.BMP",