将翻盖的位图恰好贴在鼠标点击的方砖上（不论鼠标点击在这个方砖中的什么位置），真正实现翻盖的效果

/*---------------------------------------- BRICKS1.C -- LoadBitmap Demonstration (c) Charles Petzold, 1998 ----------------------------------------*/ #include <windows.h> #include "resource.h" LRESULT CALLBACK WndProc (HWND, UINT, WPARAM, LPARAM) ; int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance, PSTR szCmdLine, int iCmdShow) { static TCHAR szAppName [] = TEXT ("Bricks1") ; 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 ("LoadBitmap Demo"), 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 message, WPARAM wParam, LPARAM lParam) { static HBITMAP hBitmap ; static int cxClient, cyClient, cxSource, cySource ; BITMAP bitmap ; HDC hdc, hdcMem ; HINSTANCE hInstance ; int x, y , mx, my, nx, ny; PAINTSTRUCT ps ; const int nStartX = 100; // 背景图坐标启始点 const int nStartY = 100; switch (message) { case WM_CREATE: hInstance = ((LPCREATESTRUCT) lParam)->hInstance ; hBitmap = LoadBitmap (hInstance, MAKEINTRESOURCE (IDM_BITMAP)) ; GetObject (hBitmap, sizeof (BITMAP), &bitmap) ; cxSource = bitmap.bmWidth ; cySource = (bitmap.bmHeight)/2 ; break; case WM_SIZE: cxClient = LOWORD (lParam) ; cyClient = HIWORD (lParam) ; break; case WM_PAINT: hdc = BeginPaint (hwnd, &ps) ; hdcMem = CreateCompatibleDC (hdc) ; SelectObject (hdcMem, hBitmap) ; for (y = nStartY ; y < cyClient - nStartY ; y += cySource) { for (x = nStartX ; x < cxClient - nStartX ; x += cxSource) { BitBlt (hdc, x, y, cxSource, cySource, hdcMem, 0, 0, SRCCOPY) ; } } DeleteDC (hdcMem) ; EndPaint (hwnd, &ps) ; break; case WM_LBUTTONDOWN: hdc = GetDC(hwnd); mx = LOWORD(lParam); my = HIWORD(lParam); // 判断鼠标坐标是否在怎个图块内，不在跳出 if(mx <nStartX || my < nStartY) break; // 左边和下边效准 x = cxClient - nStartX +cxSource - (cxClient - 2 * nStartX) % cxSource -1; y = cyClient - nStartY +cySource - (cyClient - 2 * nStartY) % cySource -1; if(mx >= x || my >= y) break; hdcMem = CreateCompatibleDC (hdc) ; SelectObject (hdcMem, hBitmap) ; // 找到单个图块的左上角坐标 x = nStartX + (mx - nStartX) / cxSource * cxSource; y = nStartY + (my - nStartY) / cySource * cySource; BitBlt (hdc, x, y, cxSource, cySource, hdcMem, 0, cySource, SRCCOPY) ; DeleteDC (hdcMem) ; ReleaseDC(hwnd, hdc); break; case WM_DESTROY: DeleteObject (hBitmap) ; PostQuitMessage (0) ; break; } return DefWindowProc (hwnd, message, wParam, lParam); }