Load JPG image and show in window

Question

How should I proceed to load an image in jpg format from a directory and then show in the following window?

    int WINAPI WinMain(HINSTANCE hInstance,
    HINSTANCE hPrevInstance,
    LPSTR lpCmdLine,
    int nCmdShow)
{
    WNDCLASSEX wcex;

    wcex.cbSize = sizeof(WNDCLASSEX);
    wcex.style = CS_HREDRAW | CS_VREDRAW;
    wcex.lpfnWndProc = WndProc;
    wcex.cbClsExtra = 0;
    wcex.cbWndExtra = 0;
    wcex.hInstance = hInstance;
    wcex.hIcon = LoadIcon(hInstance, MAKEINTRESOURCE(IDI_APPLICATION));
    wcex.hCursor = LoadCursor(NULL, IDC_ARROW);
    wcex.hbrBackground = (HBRUSH)(COLOR_WINDOW +2);
    wcex.lpszMenuName = NULL;
    wcex.lpszClassName = szWindowClass;
    wcex.hIconSm = LoadIcon(wcex.hInstance, MAKEINTRESOURCE(IDI_APPLICATION));

    if (!RegisterClassEx(&wcex))
    {
        MessageBox(NULL,
            _T("Call to RegisterClassEx failed!"),
            _T("Technology"),
            NULL);

        return 1;
    }

    hInst = hInstance;

    HWND hWnd = CreateWindow(
        szWindowClass,
        szTitle,
        WS_OVERLAPPEDWINDOW,
        CW_USEDEFAULT, CW_USEDEFAULT,
        700, 500,
        NULL,
        NULL,
        hInstance,
        NULL
        );

    if (!hWnd)
    {
        MessageBox(NULL,
            _T("Call to CreateWindow failed!"),
            _T("Technology"),
            NULL);

        return 1;
    }

    ShowWindow(hWnd,
        nCmdShow);
    UpdateWindow(hWnd);

    MSG msg;
    while (GetMessage(&msg, NULL, 0, 0))
    {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }

    return (int)msg.wParam;
}

LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    PAINTSTRUCT ps;
    HDC hdc;

    switch (message)
    {
    case WM_PAINT:

        hdc = BeginPaint(hWnd, &ps);


        EndPaint(hWnd, &ps);
        break;
    case WM_DESTROY:
        PostQuitMessage(0);
        break;
    default:
        return DefWindowProc(hWnd, message, wParam, lParam);
        break;
    }

    return 0;
}

Answer 1

To work with various image formats you can use some components of Windows Images (take a look: Iwicbitmapdecoder, this code Loading JPEG and GIF Pictures, or these libs of 3rd, Freeimage, Leadtools )

Well, anyway I’ll leave below an example of how you could load a bitmap and show it in the form:

  LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    int wmId, wmEvent;

    switch (message)
    {
        <...>

    case WM_CREATE:
        hBitmap = (HBITMAP)LoadImage(hInst, L"C:\\HYPNOS.bmp", IMAGE_BITMAP, 0, 0, LR_LOADFROMFILE);
        break;
    case WM_PAINT:
        PAINTSTRUCT     ps;
        HDC             hdc;
        BITMAP          bitmap;
        HDC             hdcMem;
        HGDIOBJ         oldBitmap;

        hdc = BeginPaint(hWnd, &ps);

        hdcMem = CreateCompatibleDC(hdc);
        oldBitmap = SelectObject(hdcMem, hBitmap);

        GetObject(hBitmap, sizeof(bitmap), &bitmap);
        BitBlt(hdc, 0, 0, bitmap.bmWidth, bitmap.bmHeight, hdcMem, 0, 0, SRCCOPY);

        SelectObject(hdcMem, oldBitmap);
        DeleteDC(hdcMem);

        EndPaint(hWnd, &ps);
        break;
    case WM_DESTROY:
        DeleteObject(hBitmap);
        PostQuitMessage(0);
        break;
    default:
        return DefWindowProc(hWnd, message, wParam, lParam);
    }
    return 0;
}