Programming Windows程式开发设计指南->第五章 例子程序7

/*_############################################################################
  _##
  _##  Programming Windows程式开发设计指南->第五章 例子程序7
  _##  Author: xwlee                        
  _##  Time: 2007.06.20 
  _##  Chang'an University
  _##  Development condition: win2003 Server+VC6.0
  _##
  _##  程序5-7  CLOVER
  _##  CLOVER.C 文件
  _##  利用复杂的剪裁区域，可以直接画出这些线条，而让Windows确定其端点
  _##  程序只是进行验证
  _## 
  _##
  _##    CLOVER.C -- Clover Drawing Program Using Regions
  _##     (c) Charles Petzold, 1998
  _##  
  _##########################################################################*/

#include <windows.h>

#include <math.h>

 

#define TWO_PI (2.0 * 3.14159)

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

int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance,

                       PSTR szCmdLine, int iCmdShow)

{

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

       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, TEXT ("This program requires Windows NT!"),

                        szAppName, MB_ICONERROR) ;

              return 0 ;

       }

    

       hwnd = CreateWindow (szAppName, TEXT ("Draw a Clover"),

                            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 iMsg, WPARAM wParam, LPARAM lParam)

{

       static HRGN hRgnClip ;

       static int  cxClient, cyClient ;

       double     fAngle, fRadius ;

       HCURSOR     hCursor ;

       HDC             hdc ;

       HRGN           hRgnTemp[6] ;

       int           i ;

       PAINTSTRUCT ps ;

       switch (iMsg)

       {

       case WM_SIZE:

              cxClient   = LOWORD (lParam) ;

              cyClient   = HIWORD (lParam) ;

              hCursor   = SetCursor (LoadCursor (NULL, IDC_WAIT)) ;

              ShowCursor (TRUE) ;

         

              if (hRgnClip)

                     DeleteObject (hRgnClip) ;

         

              hRgnTemp[0] = CreateEllipticRgn (0, cyClient / 3,

                                          cxClient / 2, 2 * cyClient / 3) ;

              hRgnTemp[1] = CreateEllipticRgn (cxClient / 2, cyClient / 3,

                                          cxClient, 2 * cyClient / 3) ;

              hRgnTemp[2] = CreateEllipticRgn (cxClient / 3, 0,

                                          2 * cxClient / 3, cyClient / 2) ;

              hRgnTemp[3] = CreateEllipticRgn (cxClient / 3, cyClient / 2,

2 * cxClient / 3, cyClient) ;

              hRgnTemp[4] = CreateRectRgn (0, 0, 1, 1) ;

              hRgnTemp[5] = CreateRectRgn (0, 0, 1, 1) ;

              hRgnClip = CreateRectRgn (0, 0, 1, 1) ;

 

              CombineRgn (hRgnTemp[4], hRgnTemp[0], hRgnTemp[1], RGN_OR) ;

              CombineRgn (hRgnTemp[5], hRgnTemp[2], hRgnTemp[3], RGN_OR) ;

              CombineRgn (hRgnClip,    hRgnTemp[4], hRgnTemp[5], RGN_XOR) ;

         

              for (i = 0 ; i < 6 ; i++)

                     DeleteObject (hRgnTemp[i]) ;

         

              SetCursor (hCursor) ;

              ShowCursor (FALSE) ;

              return 0 ;

         

       case WM_PAINT:

              hdc = BeginPaint (hwnd, &ps) ;

         

              SetViewportOrgEx (hdc, cxClient / 2, cyClient / 2, NULL) ;

          SelectClipRgn (hdc, hRgnClip) ;

              fRadius = _hypot (cxClient / 2.0, cyClient / 2.0) ;

              for (fAngle = 0.0 ; fAngle < TWO_PI ; fAngle += TWO_PI / 360)

              {

                     MoveToEx (hdc, 0, 0, NULL) ;

                     LineTo (hdc,   (int) ( fRadius * cos (fAngle) + 0.5),

                            (int) (-fRadius * sin (fAngle) + 0.5)) ;

              }

              EndPaint (hwnd, &ps) ;

              return 0 ;

       case WM_DESTROY:

              DeleteObject (hRgnClip) ;

              PostQuitMessage (0) ;

              return 0 ;

       }

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

}