linedemo.c

图形基础 GDI 的例子

/*--------------------------------------------------
   LINEDEMO.C -- Line-Drawing Demonstration Program
                 (c) Charles Petzold, 1996
  --------------------------------------------------*/

#include <windows.h>

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

int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance,
                    PSTR szCmdLine, int iCmdShow)
     {
     static char szAppName[] = "LineDemo" ;
     HWND        hwnd ;
     MSG         msg ;
     WNDCLASSEX  wndclass ;

     wndclass.cbSize        = sizeof (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 ;
     wndclass.hIconSm       = LoadIcon (NULL, IDI_APPLICATION) ;

     RegisterClassEx (&wndclass) ;

     hwnd = CreateWindow (szAppName, "Line Demonstration",
                          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 int  cxClient, cyClient ;
     HDC         hdc ;
     PAINTSTRUCT ps ;

     switch (iMsg)
          {
          case WM_SIZE:
               cxClient = LOWORD (lParam) ;
               cyClient = HIWORD (lParam) ;
               return 0 ;

          case WM_PAINT:
               hdc = BeginPaint (hwnd, &ps) ;

               Rectangle (hdc,     cxClient / 8,     cyClient / 8,
                               7 * cxClient / 8, 7 * cyClient / 8) ;

               MoveToEx  (hdc,        0,        0, NULL) ;
               LineTo    (hdc, cxClient, cyClient) ;

               MoveToEx  (hdc,        0, cyClient, NULL) ;
               LineTo    (hdc, cxClient,        0) ;

               Ellipse   (hdc,     cxClient / 8,     cyClient / 8,
                               7 * cxClient / 8, 7 * cyClient / 8) ;

               RoundRect (hdc,     cxClient / 4,     cyClient / 4,
                               3 * cxClient / 4, 3 * cyClient / 4,
                                   cxClient / 4,     cyClient / 4) ;

               EndPaint (hwnd, &ps) ;
               return 0 ;

          case WM_DESTROY:
               PostQuitMessage (0) ;
               return 0 ;
          }

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