第五章 绘图基础（LINEDEMO）

LINEDEMO程序绘制一个矩形、两条直线、一个椭圆和一个圆角矩形。该程序表明，定义了封闭矩形的这些函数确实对这些区域进行了填充，因为椭圆后面的线被隐藏了。

 /*----------------------------------------------

 LINEDEMO.C -- Line-Drawing Demonstration program

 (c) Charles Petzold, 1998

 ----------------------------------------------*/

 #include <Windows.h>

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

 int WINAPI WinMain( __in HINSTANCE hInstance

                     , __in_opt HINSTANCE hPrevInstance

                     , __in LPSTR lpCmdLine

                     , __in int nShowCmd )

 {

     static TCHAR szAppName[] = TEXT("LineDemo");

     HWND hwnd;

     MSG msg;

     WNDCLASS wndclass;

     wndclass.style = CS_HREDRAW | CS_VREDRAW;

     wndclass.lpfnWndProc = WndProc;

     wndclass.cbClsExtra = ;

     wndclass.cbWndExtra = ;

     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, TEXT("Program requires Windows NT!")

             , szAppName, MB_ICONERROR);

         return ;

     }

     hwnd = CreateWindow(szAppName, TEXT("Line Demonstration")

         , WS_OVERLAPPEDWINDOW

         , CW_USEDEFAULT, CW_USEDEFAULT

         , CW_USEDEFAULT, CW_USEDEFAULT

         , NULL, NULL, hInstance, NULL);

     ShowWindow(hwnd, nShowCmd);

     UpdateWindow(hwnd);

     while (GetMessage(&msg, NULL, , ))

     {

         TranslateMessage(&msg);

         DispatchMessage(&msg);

     }

     return msg.wParam;

 }

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

 {

     static int cxClient, cyClient;

     HDC hdc;

     PAINTSTRUCT ps;

     switch (message)

     {

     case WM_SIZE:

         cxClient = LOWORD(lParam);

         cyClient = HIWORD(lParam);

         return ;

     case WM_PAINT:

         hdc = BeginPaint(hwnd, &ps);

         Rectangle(hdc, cxClient / , cyClient /

             ,  * cxClient / ,  * cyClient / );

         MoveToEx(hdc, , , NULL);

         LineTo(hdc, cxClient, cyClient);

         MoveToEx(hdc, , cyClient, NULL);

         LineTo(hdc, cxClient, );

         Ellipse(hdc, cxClient / , cyClient/

             ,  * cxClient / ,  * cyClient / );

         RoundRect(hdc, cxClient / , cyClient /

             ,  * cxClient / ,  * cyClient /

             , cxClient/ , cyClient/ );

         EndPaint(hwnd, &ps);

         return ;

     case WM_DESTROY:

         PostQuitMessage();

         return ;

     }

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

 }

LINEDEMO.C

LINEDEMO显示结果