GDI/图象编程

开发平台：
Visual C++

DEMO5_4.C：源码内容
							  1 /****************************************************************/
  2 /*         Demo5_4   ---  Stretch Graph                         */
  3 /****************************************************************/
  4 
  5 #include <windows.h>
  6 #include "Demo5_4.h"
  7 
  8 int  PASCAL  WinMain(HANDLE, HANDLE, LPSTR, int);
  9 long FAR PASCAL MainWndProc(HWND, unsigned, WORD, LONG);
 10 
 11 void DrawRect(POINT, POINT);
 12 void CatchGraph(POINT, POINT);
 13 
 14 
 15 HDC     hMemDC;
 16 HBITMAP hBitmap;
 17 
 18 int     RegionID = IDM_REG;
 19 int     MethodID = IDM_FIT;
 20 int     MemX, MemY;
 21 
 22 /****************************************************************/
 23 /*                      WinMain()                               */
 24 /****************************************************************/
 25 
 26 int PASCAL WinMain(HANDLE hInstance, HANDLE hPrevInstance,
 27                    LPSTR lpszCmdLine, int nCmdShow)
 28 {
 29    WNDCLASS wclass;
 30    MSG      msg;
 31    HWND     hWnd;
 32    char     szName[] = "Demo5_4";
 33 
 34    if (!hPrevInstance)
 35     {
 36         wclass.style         = CS_HREDRAW | CS_VREDRAW;
 37         wclass.lpfnWndProc   = MainWndProc;
 38         wclass.cbClsExtra    = 0;
 39         wclass.cbWndExtra    = 0;
 40         wclass.hInstance     = hInstance;
 41         wclass.hIcon         = LoadIcon(NULL, IDI_APPLICATION);
 42         wclass.hCursor       = LoadCursor(NULL, IDC_ARROW);
 43         wclass.hbrBackground = GetStockObject(WHITE_BRUSH);
 44         wclass.lpszMenuName  = szName;
 45         wclass.lpszClassName = szName;
 46 
 47         if (!RegisterClass (&wclass))
 48            return (FALSE);
 49     }
 50 
 51     hWnd = CreateWindow(
 52                 szName,
 53                 "Stretch Graph" ,
 54                 WS_OVERLAPPEDWINDOW,
 55                 CW_USEDEFAULT,
 56                 CW_USEDEFAULT,
 57                 CW_USEDEFAULT,
 58                 CW_USEDEFAULT,
 59                 NULL,
 60                 NULL,
 61                 hInstance,
 62                 NULL );
 63 
 64     if (!hWnd)
 65         return (FALSE);
 66 
 67     ShowWindow(hWnd, nCmdShow);
 68     UpdateWindow(hWnd);
 69 
 70     while (GetMessage(&msg, NULL, NULL,NULL))
 71        {
 72            TranslateMessage(&msg);
 73            DispatchMessage(&msg);
 74        }
 75     return (msg.wParam);
 76 }
 77 
 78 
 79 
 80 /****************************************************************/
 81 /*                      MainWndProc()                           */
 82 /****************************************************************/
 83 
 84 long FAR PASCAL MainWndProc(HWND hWnd, unsigned message,
 85                             WORD wParam, LONG lParam)
 86 {
 87    HMENU        hMenu;
 88    HDC          hDC;
 89    PAINTSTRUCT  ps;
 90    RECT         Rect;
 91    static POINT ptSize;
 92    static BOOL  bRun = FALSE;
 93    static BOOL  bLBDown = FALSE;
 94    static POINT ptPoint1, ptPoint2, ptPrePoint;
 95 
 96    switch (message)
 97     {
 98       case WM_CREATE :
 99                 hMenu = GetMenu(hWnd);
100                 CheckMenuItem(hMenu, RegionID,
101                               MF_CHECKED);
102                 CheckMenuItem(hMenu, MethodID,
103                               MF_CHECKED);
104 
105                 hDC = GetDC(hWnd);
106 
107                 MemX = GetSystemMetrics(SM_CXSCREEN);
108                 MemY = GetSystemMetrics(SM_CYSCREEN);
109 
110                 hMemDC = CreateCompatibleDC(hDC);
111                 hBitmap = CreateCompatibleBitmap(hDC,
112                                          MemX, MemY);
113                 SelectObject(hMemDC, hBitmap);
114 
115                 PatBlt(hMemDC, 0, 0, MemX, MemY, WHITENESS);
116 
117                 ReleaseDC(hWnd, hDC);
118                 return (0);
119 
120       case WM_COMMAND :
121                 switch (wParam)
122                   {
123                     case IDM_REG :
124                     case IDM_WIN :
125                     case IDM_SCR :
126 
127                          hMenu = GetMenu(hWnd);
128                          if (RegionID == wParam)
129                             break;
130 
131                          CheckMenuItem(hMenu, RegionID,
132                                         MF_UNCHECKED);
133                          RegionID = wParam;
134                          CheckMenuItem(hMenu, RegionID,
135                                         MF_CHECKED);
136                          break;
137 
138                     case IDM_FIT :
139                     case IDM_SAME :
140 
141                          hMenu = GetMenu(hWnd);
142                          if (MethodID == wParam)
143                             break;
144 
145                          CheckMenuItem(hMenu, MethodID,
146                                         MF_UNCHECKED);
147                          MethodID = wParam;
148                          CheckMenuItem(hMenu, MethodID,
149                                         MF_CHECKED);
150 
151                          InvalidateRect(hWnd, NULL, TRUE);
152                          break;
153 
154                     case IDM_RUN :
155                          switch (RegionID)
156                           {
157                             case IDM_REG :
158                                SetCapture(hWnd);
159                                SetCursor(LoadCursor(
160                                     NULL, IDC_CROSS));
161                                bRun = TRUE;
162                                break;
163 
164                             case IDM_SCR :
165 
166                                ptPoint1.x = 0;
167                                ptPoint1.y = 0;
168                                ptPoint2.x = MemX;
169                                ptPoint2.y = MemY;
170 
171                                CatchGraph(ptPoint1,
172                                           ptPoint2);
173                                InvalidateRect(hWnd, NULL,
174                                               TRUE);
175                                break;
176 
177                             case IDM_WIN :
178 
179                                GetWindowRect(hWnd, &Rect);
180                                ptPoint1.x = Rect.left;
181                                ptPoint1.y = Rect.top;
182                                ptPoint2.x = Rect.right;
183                                ptPoint2.y = Rect.bottom;
184 
185                                CatchGraph(ptPoint1,
186                                           ptPoint2);
187                                InvalidateRect(hWnd, NULL,
188                                               TRUE);
189                                break;
190                           }
191                          break;
192 
193                     case IDM_EXIT :
194                          DestroyWindow(hWnd);
195                          break;
196                   }
197                 return (0);
198 
199       case WM_LBUTTONDOWN :
200                 if (bRun)
201                   {
202                     bLBDown = TRUE;
203                     ptPoint1 = MAKEPOINT(lParam);
204                     ClientToScreen(hWnd, &ptPoint1);
205                     ptPrePoint = ptPoint1;
206                   }
207                 return (0);
208 
209       case WM_MOUSEMOVE :
210                 if (bLBDown)
211                   {
212                     ptPoint2 = MAKEPOINT(lParam);
213                     ClientToScreen(hWnd, &ptPoint2);
214 
215                     DrawRect(ptPoint1, ptPrePoint);
216                     DrawRect(ptPoint1, ptPoint2);
217 
218                     ptPrePoint = ptPoint2;
219                   }
220                 return (0);
221 
222       case WM_LBUTTONUP :
223                 if (bLBDown)
224                   {
225                     bLBDown = FALSE;
226                     bRun = FALSE;
227 
228                     DrawRect(ptPoint1, ptPoint2);
229 
230                     SetCursor(LoadCursor(NULL, IDC_WAIT));
231                     CatchGraph(ptPoint1, ptPoint2);
232                     SetCursor(LoadCursor(NULL, IDC_ARROW));
233 
234                     ReleaseCapture();
235                     InvalidateRect(hWnd, NULL, TRUE);
236                   }
237                 return (0);
238 
239       case WM_SIZE :
240                 ptSize = MAKEPOINT(lParam);
241                 InvalidateRect(hWnd, NULL, TRUE);
242                 break;
243 
244       case WM_PAINT :
245                 hDC = BeginPaint(hWnd, &ps);
246 
247                 SetCursor(LoadCursor(NULL, IDC_WAIT));
248                 if (MethodID == IDM_FIT)
249                    StretchBlt(hDC, 0, 0,
250                               ptSize.x, ptSize.y,
251                               hMemDC, 0, 0,
252                               ptPoint2.x-ptPoint1.x,
253                               ptPoint2.y-ptPoint1.y,
254                               SRCCOPY);
255                 else
256                    BitBlt(hDC, 0, 0,
257                           ptPoint2.x-ptPoint1.x,
258                           ptPoint2.y-ptPoint1.y,
259                           hMemDC, 0, 0,
260                           SRCCOPY);
261 
262                 SetCursor(LoadCursor(NULL, IDC_ARROW));
263 
264                 EndPaint(hWnd, &ps);
265                 return (0);
266 
267       case WM_DESTROY :
268                 DeleteDC(hMemDC);
269                 DeleteObject(hBitmap);
270                 PostQuitMessage(0);
271                 return (0);
272     }
273 
274    return(DefWindowProc(hWnd, message, wParam, lParam));
275 }
276 
277 
278 
279 void DrawRect(POINT ptP1, POINT ptP2)
280 {
281    HDC hDC;
282 
283    hDC = CreateDC("DISPLAY", NULL, NULL, NULL);
284 
285    SetROP2(hDC, R2_NOT);
286    Rectangle(hDC, ptP1.x, ptP1.y, ptP2.x, ptP2.y);
287 
288    DeleteDC(hDC);
289 }
290 
291 
292 
293 void CatchGraph(POINT ptP1, POINT ptP2)
294 {
295    HDC  hDC;
296 
297    hDC = CreateDC("DISPLAY", NULL, NULL, NULL);
298 
299    PatBlt(hMemDC, 0, 0,
300             MemX, MemY, WHITENESS);
301    BitBlt(hMemDC, 0, 0,
302             ptP2.x-ptP1.x, ptP2.y-ptP1.y,
303           hDC, ptP1.x, ptP1.y,
304           SRCCOPY);
305 
306    DeleteDC(hDC);
307 }

						