Mouse Click Example

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#include <windows.h>

LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);

int WINAPI WinMain(HINSTANCE hInstance,
                   HINSTANCE hPrevInstance,
                   LPSTR lpCmdLine,
                   int nCmdShow)
{
    const wchar_t CLASS_NAME[] = L"MyWindowClass";

    WNDCLASSEXW wc = {0};
    MSG msg;

    // Register the window class
    wc.cbSize = sizeof(WNDCLASSEXW);
    wc.lpfnWndProc = WndProc;
    wc.hInstance = hInstance;
    wc.hIcon = LoadIcon(NULL, IDI_APPLICATION);
    wc.hCursor = LoadCursor(NULL, IDC_ARROW);
    wc.hbrBackground = GetSysColorBrush(COLOR_WINDOW);
    wc.lpszClassName = CLASS_NAME;
    wc.hIconSm = LoadIcon(NULL, IDI_APPLICATION);

    if (!RegisterClassExW(&wc))
        return 0;

    HWND hwnd = CreateWindowExW(
        WS_EX_CLIENTEDGE,
        CLASS_NAME,
        L"Mouse Click Demo",
        WS_OVERLAPPEDWINDOW | WS_VISIBLE,
        CW_USEDEFAULT,
        CW_USEDEFAULT,
        700,
        200,
        NULL,
        NULL,
        hInstance,
        NULL);

    if (!hwnd)
        return 0;

    // Message loop
    while (GetMessage(&msg, NULL, 0, 0) > 0)
    {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }

    return static_cast<int>(msg.wParam);
}

LRESULT CALLBACK WndProc(HWND hwnd,
                         UINT message,
                         WPARAM wParam,
                         LPARAM lParam)
{
    static wchar_t mouseStr[255] = L"";
    static int xPos = 0;
    static int yPos = 0;

    switch (message)
    {
        case WM_LBUTTONDOWN:

            xPos = LOWORD(lParam);
            yPos = HIWORD(lParam);

            if (wParam & MK_SHIFT)
            {
                wsprintfW(mouseStr,
                          L"Shift + Left Button Down at %d,%d",
                          xPos, yPos);
            }
            else if (wParam & MK_CONTROL)
            {
                wsprintfW(mouseStr,
                          L"Ctrl + Left Button Down at %d,%d",
                          xPos, yPos);
            }
            else if (wParam & MK_RBUTTON)
            {
                wsprintfW(mouseStr,
                          L"Left and Right Buttons Down at %d,%d",
                          xPos, yPos);
            }
            else
            {
                wsprintfW(mouseStr,
                          L"Left Button Down at %d,%d",
                          xPos, yPos);
            }

            InvalidateRect(hwnd, NULL, TRUE);
            return 0;

        case WM_LBUTTONUP:

            xPos = LOWORD(lParam);
            yPos = HIWORD(lParam);

            wsprintfW(mouseStr,
                      L"Left Button Up at %d,%d",
                      xPos, yPos);

            InvalidateRect(hwnd, NULL, TRUE);
            return 0;

        case WM_RBUTTONDOWN:

            xPos = LOWORD(lParam);
            yPos = HIWORD(lParam);

            wsprintfW(mouseStr,
                      L"Right Button Down at %d,%d",
                      xPos, yPos);

            InvalidateRect(hwnd, NULL, TRUE);
            return 0;

        case WM_RBUTTONUP:

            xPos = LOWORD(lParam);
            yPos = HIWORD(lParam);

            wsprintfW(mouseStr,
                      L"Right Button Up at %d,%d",
                      xPos, yPos);

            InvalidateRect(hwnd, NULL, TRUE);
            return 0;

        case WM_PAINT:
        {
            PAINTSTRUCT ps;
            HDC hdc = BeginPaint(hwnd, &ps);

            TextOutW(hdc,
                     xPos,
                     yPos,
                     mouseStr,
                     lstrlenW(mouseStr));

            EndPaint(hwnd, &ps);
            return 0;
        }

        case WM_DESTROY:

            PostQuitMessage(0);
            return 0;
    }

    return DefWindowProcW(hwnd,
                          message,
                          wParam,
                          lParam);
}