VC6运行鼠标控制旋转的正方形 ，掌握程序鼠标交互方法，尝试为其添加键盘与菜单控制，实 现同样功能

以下是一个VC6运行鼠标控制旋转正方形的示例程序，其中包含了鼠标交互的代码：

#include <windows.h>

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

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
    PSTR szCmdLine, int iCmdShow)
{
    static char szAppName[] = "RotateSquare";
    HWND        hwnd;
    MSG         msg;
    WNDCLASS    wndclass;

    wndclass.style = CS_HREDRAW | CS_VREDRAW;
    wndclass.lpfnWndProc = WndProc;
    wndclass.cbClsExtra = 0;
    wndclass.cbWndExtra = 0;
    wndclass.hInstance = hInstance;
    wndclass.hIcon = LoadIcon(NULL, IDI_APPLICATION);
    wndclass.hCursor = LoadCursor(NULL, IDC_ARROW);
    wndclass.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);
    wndclass.lpszMenuName = NULL;
    wndclass.lpszClassName = szAppName;

    if (!RegisterClass(&wndclass))
    {
        MessageBox(NULL, "This program requires Windows NT!", szAppName, MB_ICONERROR);
        return 0;
    }

    hwnd = CreateWindow(szAppName, "Rotate Square",
        WS_OVERLAPPEDWINDOW,
        CW_USEDEFAULT, CW_USEDEFAULT,
        CW_USEDEFAULT, CW_USEDEFAULT,
        NULL, NULL, hInstance, NULL);

    ShowWindow(hwnd, iCmdShow);
    UpdateWindow(hwnd);

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

    return msg.wParam;
}

LRESULT CALLBACK WndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    static int  cxClient, cyClient;
    static POINT ptCenter;
    static POINT ptSquare[] = { {-50,-50},{50,-50},{50,50},{-50,50},{-50,-50} };
    static int  iAngle;

    HDC         hdc;
    int         i;
    PAINTSTRUCT ps;

    switch (message)
    {
    case WM_CREATE:
        ptCenter.x = (int)(0.5 * cxClient);
        ptCenter.y = (int)(0.5 * cyClient);
        return 0;

    case WM_SIZE:
        cxClient = LOWORD(lParam);
        cyClient = HIWORD(lParam);

        ptCenter.x = (int)(0.5 * cxClient);
        ptCenter.y = (int)(0.5 * cyClient);
        return 0;

    case WM_KEYDOWN:
        switch (wParam)
        {
        case VK_LEFT:
            iAngle -= 5;
            InvalidateRect(hwnd, NULL, TRUE);
            break;

        case VK_RIGHT:
            iAngle += 5;
            InvalidateRect(hwnd, NULL, TRUE);
            break;
        }
        return 0;

    case WM_COMMAND:
        switch (LOWORD(wParam))
        {
        case IDM_EXIT:
            DestroyWindow(hwnd);
            break;

        case IDM_ABOUT:
            MessageBox(hwnd, "Rotate Square\n\n(c) 2021 YourName\n\nhttps://www.example.com", "About", MB_ICONINFORMATION);
            break;
        }
        return 0;

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

        SelectObject(hdc, GetStockObject(BLACK_PEN));

        for (i = 0; i < 4; i++)
        {
            ptSquare[i].x = (int)(50 * cos(iAngle + i * 3.14159 / 2) + ptCenter.x);
            ptSquare[i].y = (int)(-50 * sin(iAngle + i * 3.14159 / 2) + ptCenter.y);
        }

        Polyline(hdc, ptSquare, 5);

        EndPaint(hwnd, &ps);
        return 0;

    case WM_DESTROY:
        PostQuitMessage(0);
        return 0;
    }

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

这个程序可以通过鼠标控制正方形的旋转，按下左右箭头键可以使正方形向左或向右旋转，同时可以添加菜单控制。在代码中，菜单控制的实现使用了 WM_COMMAND 消息，在菜单项被点击时触发相应的操作。

注意，在使用菜单控制时，需要在窗口的 WndProc 函数中处理 WM_COMMAND 消息，根据菜单项的 ID 进行相应的操作。在示例程序中，我们添加了名为 IDM_EXIT 和 IDM_ABOUT 的两个菜单项，分别用于退出程序和显示关于对话框。我们可以在程序的 WndProc 函数中添加以下代码来处理这两个菜单项的点击事件：

switch (LOWORD(wParam))
{
case IDM_EXIT:
    DestroyWindow(hwnd);
    break;

case IDM_ABOUT:
    MessageBox(hwnd, "Rotate Square\n\n(c) 2021 YourName\n\nhttps://www.example.com", "About", MB_ICONINFORMATION);
    break;
}