LRESULT CALLBACK WndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)

{

    HDC hdc;

    PAINTSTRUCT ps;

    static RECT rect,rect2,rect3;

    static cxClient, cyClient;

    static HBRUSH hBrush, hOldBrush;

    POINT pt;

    switch (message)

    {

    case WM_SIZE:

        cxClient = LOWORD(lParam);

        cyClient = HIWORD(lParam);

        break;

    case WM_LBUTTONDOWN:

        pt.x = LOWORD(lParam);

        pt.y = HIWORD(lParam);

        if (PtInRect(&rect2,pt))

        {

            MessageBox(NULL, L"clicked", L"info", NULL);

        }

        break;

    case WM_PAINT:

        hdc = BeginPaint(hwnd, &ps);

//处理矩形

//         rect.left = cxClient / 2 - 50;

//         rect.right = cxClient / 2 + 50;

//         rect.top = cyClient / 2 - 50;

//         rect.bottom = cyClient / 2 + 50;

        hBrush = CreateSolidBrush(RGB(,,));

//1.fillrect    填充矩形

        //FillRect(hdc, &rect, hBrush);

//2.framerect    改画笔为画刷来绘制边框

        //FrameRect(hdc, &rect, hBrush);

//3.invertrect    翻转矩形内所有的像素

        //InvertRect(hdc, &rect);

//4.生成矩形SetRect

        SetRect(&rect, cxClient /  - , cyClient /  - , cxClient/ + , cyClient/ + );

//5.偏移矩形OffsetRect

        OffsetRect(&rect, -, -);

        FillRect(hdc, &rect, hBrush);

        InvertRect(hdc, &rect);    //先显示图像，后翻转

//6.增大减小，长宽同时InflateRect

        SetRect(&rect, cxClient /  - , cyClient /  - , cxClient /  + , cyClient /  + );

        InflateRect(&rect, , );

        FillRect(hdc, &rect, hBrush);

//7.setrectEmpty    设置矩形为空

        FillRect(hdc, &rect, hBrush);    //不会显示

//8.copyrect    多用在映射中

        CopyRect(&rect2, &rect);    //将rect的坐标拷贝给rect2

        SetRectEmpty(&rect);//将矩形的各个坐标设为0,则会显示rect2

        hBrush = CreateSolidBrush(RGB(, , ));

        FillRect(hdc, &rect2, hBrush);

//9.intersectrect    两个矩形交集

//10.unionrect        两个矩形并集

//11.Isrectempty    判断是否为空

//12.ptinrect        判断点是否在矩形中（重要）

        EndPaint(hwnd, &ps);

        break;

    case WM_DESTROY:

        PostQuitMessage();

        return ;

    }

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

}