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