Programming Windows程式開發設計指南->第五章 例子程式3

/*_############################################################################
  _##
  _##  Programming Windows程式開發設計指南->第五章 例子程式3
  _##  Author: xwlee                        
  _##  Time: 2007.06.18 
  _##  Chang'an University
  _##  Development condition: win2003 Server+VC6.0
  _##
  _##  程式5-3  BEZIER
  _##  BEZIER.C 檔案
  _##  畫貝茲路徑
  _##  程式只是進行驗證
  _## 
  _##
  _##    BEZIER.C -- Bezier Splines Demo
  _##     (c) Charles Petzold, 1998
  _##  
  _##########################################################################*/

#include <windows.h>

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

int WINAPI WinMain (  HINSTANCE hInstance, HINSTANCE hPrevInstance,
                        PSTR szCmdLine, int iCmdShow)
{
       static TCHAR szAppName[] = TEXT ("Bezier") ;
       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 ("Program requires Windows NT!"),
                                   szAppName, MB_ICONERROR) ;
                 return 0 ;
       }
    
       hwnd = CreateWindow (       szAppName, TEXT ("Bezier Splines"),
                                            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 ;
}

 
void DrawBezier (HDC hdc, POINT apt[])
{
       PolyBezier (hdc, apt, 4) ;

       MoveToEx (hdc, apt[0].x, apt[0].y, NULL) ;
       LineTo   (hdc, apt[1].x, apt[1].y) ;
   
       MoveToEx (hdc, apt[2].x, apt[2].y, NULL) ;
       LineTo   (hdc, apt[3].x, apt[3].y) ;
}

LRESULT CALLBACK WndProc (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
       static POINT apt[4] ;
       HDC          hdc ;
       int          cxClient, cyClient ;
       PAINTSTRUCT  ps ;

       switch (message)
       {
       case WM_SIZE:
              cxClient = LOWORD (lParam) ;
              cyClient = HIWORD (lParam) ;
                     apt[0].x = cxClient / 4 ;
                     apt[0].y = cyClient / 2 ;

     
                     apt[1].x = cxClient / 2 ;
                     apt[1].y = cyClient / 4 ;
         

                     apt[2].x = cxClient / 2 ;
                     apt[2].y = 3 * cyClient / 4 ;

         
                     apt[3].x = 3 * cxClient / 4 ;
                     apt[3].y = cyClient / 2 ;

                     return 0 ;
 
       case WM_LBUTTONDOWN:

       case WM_RBUTTONDOWN:

       case WM_MOUSEMOVE:

              if (wParam & MK_LBUTTON || wParam & MK_RBUTTON)
              {
                     hdc = GetDC (hwnd) ;
                     SelectObject (hdc, GetStockObject (WHITE_PEN)) ;
                     DrawBezier (hdc, apt) ;

                     if (wParam & MK_LBUTTON)
                     {
                            apt[1].x = LOWORD (lParam) ;
                            apt[1].y = HIWORD (lParam) ;
                     }

            
                    if (wParam & MK_RBUTTON)
                     {
                                   apt[2].x = LOWORD (lParam) ;
                                   apt[2].y = HIWORD (lParam) ;
                     }

                     SelectObject (hdc, GetStockObject (BLACK_PEN)) ;
                     DrawBezier (hdc, apt) ;
                     ReleaseDC (hwnd, hdc) ;
              }
                     return 0 ;

       case       WM_PAINT:
              InvalidateRect (hwnd, NULL, TRUE) ;
              hdc = BeginPaint (hwnd, &ps) ;
              DrawBezier (hdc, apt) ;
              EndPaint (hwnd, &ps) ;
              return 0 ;
        

       case WM_DESTROY:
              PostQuitMessage (0) ;
              return 0 ;
       }
       return DefWindowProc (hwnd, message, wParam, lParam) ;
}