demo5_3.c

WINDOWS图形编程随书光盘

  1 /****************************************************************/
  2 /*         Demo5_3   ---  Moving Region                         */
  3 /****************************************************************/
  4 
  5 #include <windows.h>
  6 #include "Demo5_3.h"
  7 
  8 int  PASCAL  WinMain(HANDLE, HANDLE, LPSTR, int);
  9 long FAR PASCAL MainWndProc(HWND, unsigned, WORD, LONG);
 10 
 11 void MakeScreenBitmap(HDC);
 12 void DrawRegion(HDC, int, int, int, int, int);
 13 void GetViewSize(POINT *);
 14 void Run(HWND);
 15 
 16 
 17 HDC     hMemDC;
 18 HBITMAP hBitmap;
 19 HRGN    hPreRgn;
 20 
 21 int     MemX, MemY;
 22 int     RegionTypeID = IDM_CIRCLE;
 23 int     ViewSizeID = IDM_75;
 24 
 25 /****************************************************************/
 26 /*                      WinMain()                               */
 27 /****************************************************************/
 28 
 29 int PASCAL WinMain(HANDLE hInstance, HANDLE hPrevInstance,
 30                    LPSTR lpszCmdLine, int nCmdShow)
 31 {
 32    WNDCLASS wclass;
 33    MSG      msg;
 34    HWND     hWnd;
 35    char     szName[] = "Demo5_3";
 36 
 37    if (!hPrevInstance)
 38     {
 39         wclass.style         = CS_HREDRAW | CS_VREDRAW;
 40         wclass.lpfnWndProc   = MainWndProc;
 41         wclass.cbClsExtra    = 0;
 42         wclass.cbWndExtra    = 0;
 43         wclass.hInstance     = hInstance;
 44         wclass.hIcon         = LoadIcon(NULL, IDI_APPLICATION);
 45         wclass.hCursor       = LoadCursor(NULL, IDC_ARROW);
 46         wclass.hbrBackground = GetStockObject(WHITE_BRUSH);
 47         wclass.lpszMenuName  = szName;
 48         wclass.lpszClassName = szName;
 49 
 50         if (!RegisterClass (&wclass))
 51            return (FALSE);
 52     }
 53 
 54     hWnd = CreateWindow(
 55                 szName,
 56                 "Moving Region" ,
 57                 WS_OVERLAPPEDWINDOW,
 58                 CW_USEDEFAULT,
 59                 CW_USEDEFAULT,
 60                 CW_USEDEFAULT,
 61                 CW_USEDEFAULT,
 62                 NULL,
 63                 NULL,
 64                 hInstance,
 65                 NULL );
 66 
 67     if (!hWnd)
 68         return (FALSE);
 69 
 70     ShowWindow(hWnd, nCmdShow);
 71     UpdateWindow(hWnd);
 72 
 73     while (GetMessage(&msg, NULL, NULL,NULL))
 74        {
 75            TranslateMessage(&msg);
 76            DispatchMessage(&msg);
 77        }
 78     return (msg.wParam);
 79 }
 80 
 81 
 82 
 83 /****************************************************************/
 84 /*                      MainWndProc()                           */
 85 /****************************************************************/
 86 
 87 long FAR PASCAL MainWndProc(HWND hWnd, unsigned message,
 88                             WORD wParam, LONG lParam)
 89 {
 90    HMENU           hMenu;
 91 
 92    switch (message)
 93     {
 94       case WM_CREATE :
 95                 hMenu = GetMenu(hWnd);
 96                 CheckMenuItem(hMenu, RegionTypeID,
 97                               MF_CHECKED);
 98                 CheckMenuItem(hMenu, ViewSizeID,
 99                               MF_CHECKED);
100                 return (0);
101 
102       case WM_COMMAND :
103                 switch (wParam)
104                   {
105                     case IDM_CIRCLE :
106                     case IDM_SQUARE :
107 
108                          hMenu = GetMenu(hWnd);
109                          if (RegionTypeID == wParam)
110                             break;
111 
112                          CheckMenuItem(hMenu, RegionTypeID,
113                                         MF_UNCHECKED);
114                          RegionTypeID = wParam;
115                          CheckMenuItem(hMenu, RegionTypeID,
116                                         MF_CHECKED);
117                          break;
118 
119                     case IDM_50 :
120                     case IDM_75 :
121                     case IDM_100 :
122                     case IDM_150 :
123 
124                          hMenu = GetMenu(hWnd);
125                          if (ViewSizeID == wParam)
126                             break;
127 
128                          CheckMenuItem(hMenu, ViewSizeID,
129                                         MF_UNCHECKED);
130                          ViewSizeID = wParam;
131                          CheckMenuItem(hMenu, ViewSizeID,
132                                         MF_CHECKED);
133                          break;
134 
135                     case IDM_RUN :
136                          Run(hWnd);
137                          break;
138 
139                     case IDM_EXIT :
140                          DestroyWindow(hWnd);
141                          break;
142                   }
143                 return (0);
144 
145       case WM_DESTROY :
146                 PostQuitMessage(0);
147                 return (0);
148     }
149 
150   return(DefWindowProc(hWnd, message, wParam, lParam));
151 }
152 
153 
154 void MakeScreenBitmap(HDC hDC)
155 {
156    hMemDC = CreateCompatibleDC(hDC);
157 
158    MemX = GetSystemMetrics(SM_CXSCREEN);
159    MemY = GetSystemMetrics(SM_CYSCREEN);
160 
161    hBitmap = CreateCompatibleBitmap(hDC, MemX, MemY);
162    SelectObject(hMemDC, hBitmap);
163 
164    BitBlt(hMemDC, 0, 0, MemX, MemY, hDC, 0, 0, SRCCOPY);
165    PatBlt(hDC, 0, 0, MemX, MemY, BLACKNESS);
166 }
167 
168 
169 void DrawRegion(HDC hDC, int MX, int MY,
170                 int Width, int Height, int bFirst)
171 {
172    HRGN    hRgn, hDstRgn;
173    static  int PreMX, PreMY;
174 
175    switch (RegionTypeID)
176     {
177       case IDM_CIRCLE :
178              hRgn = CreateEllipticRgn(
179                             MX-Width/2, MY-Height/2,
180                             MX+Width/2, MY+Height/2);
181              break;
182       case IDM_SQUARE :
183              hRgn = CreateRectRgn(
184                             MX-Width/2, MY-Height/2,
185                             MX+Width/2, MY+Height/2);
186              break;
187     }
188 
189    SelectObject(hDC, hRgn);
190    BitBlt(hDC, MX-Width/2, MY-Height/2,
191           Width, Height,
192           hMemDC, MX-Width/2, MY-Height/2,
193           SRCCOPY);
194 
195    if (! bFirst)
196      {
197        hDstRgn = CreateRectRgn(0, 0, 1, 1);
198        CombineRgn(hDstRgn, hPreRgn, hRgn, RGN_DIFF);
199 
200        SelectObject(hDC, hDstRgn);
201        PatBlt(hDC, PreMX-Width/2, PreMY-Height/2,
202                    Width, Height, BLACKNESS);
203        SelectObject(hDC, hRgn);
204 
205        DeleteObject(hDstRgn);
206        DeleteObject(hPreRgn);
207      }
208 
209    hPreRgn = hRgn;
210 
211    PreMX = MX;
212    PreMY = MY;
213 
214    bFirst = FALSE;
215 }
216 
217 
218 void GetViewSize(POINT *lpSize)
219 {
220    switch (ViewSizeID)
221     {
222       case IDM_50 :
223                 lpSize->x = 50;
224                 break;
225 
226       case IDM_75 :
227                 lpSize->x = 75;
228                 break;
229 
230       case IDM_100 :
231                 lpSize->x = 100;
232                 break;
233 
234       case IDM_150 :
235                 lpSize->x = 150;
236                 break;
237     }
238 
239    lpSize->y = -lpSize->x;
240 }
241 
242 
243 void Run(HWND hWnd)
244 {
245    int     KeyState;
246    HDC     hDC;
247    HRGN    hScrRgn;
248    POINT   Pt, ptSize;
249 
250    SetCapture(hWnd);
251    ShowCursor(FALSE);
252 
253    hDC = CreateDC("DISPLAY", NULL, NULL, NULL);
254    MakeScreenBitmap(hDC);
255 
256    GetViewSize(&ptSize);
257    SetMapMode(hDC, MM_LOENGLISH);
258    LPtoDP(hDC, &ptSize, 1);
259    SetMapMode(hDC, MM_TEXT);
260 
261    GetCursorPos(&Pt);
262    DrawRegion(hDC, Pt.x, Pt.y, ptSize.x, ptSize.y, 1);
263 
264    for (;;)
265     {
266       KeyState = GetAsyncKeyState(VK_SPACE);
267       if (KeyState & 0x8000)
268         break;
269 
270       GetCursorPos(&Pt);
271       DrawRegion(hDC, Pt.x, Pt.y, ptSize.x, ptSize.y, 0);
272     }
273 
274    hScrRgn = CreateRectRgn(0, 0, MemX, MemY);
275    SelectObject(hDC, hScrRgn);
276    BitBlt(hDC, 0, 0, MemX, MemY, hMemDC, 0, 0, SRCCOPY);
277 
278    DeleteDC(hMemDC);
279    DeleteObject(hBitmap);
280    DeleteObject(hPreRgn);
281    DeleteObject(hScrRgn);
282 
283    DeleteDC(hDC);
284 
285    ReleaseCapture();
286    ShowCursor(TRUE);
287 }