怎样在实现橡皮擦功能,能擦除位图中的杂点

#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 ("Sketch") ;

           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 ("Sketch"),

                            WS_OVERLAPPEDWINDOW,

                            CW_USEDEFAULT, CW_USEDEFAULT,

                            CW_USEDEFAULT, CW_USEDEFAULT,

                           NULL, NULL, hInstance, NULL) ;
                   if (hwnd == NULL)

           {

                  MessageBox (  NULL, TEXT ("Not enough memory to create bitmap!"),

                                  szAppName, MB_ICONERROR) ;

                  return 0 ;

    }
                   ShowWindow (hwnd, iCmdShow) ;

          UpdateWindow (hwnd) ;
                   while (GetMessage (&msg, NULL, 0, 0))

    {

                                  TranslateMessage (&msg) ;

                                  DispatchMessage (&msg) ;

    }

   return msg.wParam ;

}
        void GetLargestDisplayMode (int * pcxBitmap, int * pcyBitmap)

{

           DEVMODE       devmode ;

           int           iModeNum = 0 ;
                   * pcxBitmap = * pcyBitmap = 0 ;
                   ZeroMemory (&devmode, sizeof (DEVMODE)) ;

           devmode.dmSize = sizeof (DEVMODE) ;



           while (EnumDisplaySettings (NULL, iModeNum++, &devmode))

           {

                  * pcxBitmap = max (* pcxBitmap, (int) devmode.dmPelsWidth) ;

                  * pcyBitmap = max (* pcyBitmap, (int) devmode.dmPelsHeight) ;

           }

}

LRESULT CALLBACK WndProc ( HWND hwnd, UINT message, WPARAM wParam,LPARAM lParam)

{

           static BOOL   fLeftButtonDown, fRightButtonDown ;

           static HBITMAP hBitmap ;

           static HDC            hdcMem ;

           static int           cxBitmap, cyBitmap, cxClient, cyClient, xMouse, yMouse ;

           HDC                                  hdc ;

           PAINTSTRUCT           ps ;



           switch (message)

           {

           case   WM_CREATE:

                         GetLargestDisplayMode (&cxBitmap, &cyBitmap) ;
                                  hdc = GetDC (hwnd) ;

                          hBitmap = CreateCompatibleBitmap (hdc, cxBitmap, cyBitmap) ;

                          hdcMem  = CreateCompatibleDC (hdc) ;

                        ReleaseDC (hwnd, hdc) ;
                         if (!hBitmap)                                // no memory for bitmap

                  {

                                  DeleteDC (hdcMem) ;

                                  return -1 ;

                  }
                                  SelectObject (hdcMem, hBitmap) ;

                          PatBlt (hdcMem, 0, 0, cxBitmap, cyBitmap, WHITENESS) ;

                          return 0 ;

           case   WM_SIZE:

                          cxClient = LOWORD (lParam) ;

                          cyClient = HIWORD (lParam) ;

                          return 0 ;
                   case   WM_LBUTTONDOWN:

                          if (!fRightButtonDown)

                                                 SetCapture (hwnd) ;
                                 xMouse = LOWORD (lParam) ;

                          yMouse = HIWORD (lParam) ;

                          fLeftButtonDown = TRUE ;

                          return 0 ;
                   case   WM_LBUTTONUP:

                          if (fLeftButtonDown)

                                                 SetCapture (NULL) ;



                          fLeftButtonDown = FALSE ;

                          return 0 ;



           case   WM_RBUTTONDOWN:

                          if (!fLeftButtonDown)

                                                 SetCapture (hwnd) ;



                          xMouse = LOWORD (lParam) ;

                          yMouse = HIWORD (lParam) ;

                          fRightButtonDown = TRUE ;

                         return 0 ;



           case   WM_RBUTTONUP:

                          if (fRightButtonDown)

                                  SetCapture (NULL) ;



                          fRightButtonDown = FALSE ;

                          return 0 ;
                   case   WM_MOUSEMOVE:

                          if (!fLeftButtonDown && !fRightButtonDown)

                                return 0 ;
                                  hdc = GetDC (hwnd) ;
                                  SelectObject (hdc,

                               GetStockObject (fLeftButtonDown ? BLACK_PEN : WHITE_PEN)) ;
                                  SelectObject (hdcMem,

                                  GetStockObject (fLeftButtonDown ? BLACK_PEN : WHITE_PEN)) ;
                                  MoveToEx (hdc,    xMouse, yMouse, NULL) ;

                         MoveToEx (hdcMem, xMouse, yMouse, NULL) ;
                                  xMouse = (short) LOWORD (lParam) ;

                          yMouse = (short) HIWORD (lParam) ;
                                  LineTo (hdc,    xMouse, yMouse) ;

                          LineTo (hdcMem, xMouse, yMouse) ;
                                  ReleaseDC (hwnd, hdc) ;

                          return 0 ;
                   case   WM_PAINT:

                          hdc = BeginPaint (hwnd, &ps) ;

                          BitBlt (hdc, 0, 0, cxClient, cyClient, hdcMem, 0, 0, SRCCOPY) ;
                                  EndPaint (hwnd, &ps) ;

                          return 0 ;
                  case   WM_DESTROY:

                          DeleteDC (hdcMem) ;

                          DeleteObject (hBitmap) ;

                          PostQuitMessage (0) ;

                          return 0 ;

           }

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

}
怎么不行，给你一个程序，或许有用，它是鼠标左键画画，右键擦写

我想你读的位图是bmp格式吧
分以下几步走：
1、调用CreateDIBitmap函数生成一个指向DDB的句柄hbitmap
2、调用CreateCompatibleDC生成一个和当前窗口兼容的内存DC hmemdc
3、调用 SelectObject把hbitmap选入到hmemdc中
这样你就可以对hbitmap进行操作拉^_^
然后操作完成以后再存储为bmp格式,即完成DDB到DIB的转换
大体就是这样

当然可能在相应onpaint里面调用bitblt函数看一下修改的效果

还是不行,我的程序是这样的:用文件菜单下的“打开”读取一幅图片，然后在显示的图片上进行修改。
CImageDoc* pDoc = GetDocument();// 获取文档
HGLOBAL hDIB = pDoc->GetHObject();//DIB句柄
我现在的问题是怎么样把显示的图片的句柄选入内存。

调试易

怎样在实现橡皮擦功能,能擦除位图中的杂点

解决方案 »