我们都知道消息循环的函数,下面可以用别的函数来代替
while(GetMessage(&msg,NULL,0,0)){ TranslateMessage(&msg); DispatchMessage(&msg); } return msg.wParam;
替换成
while(TRUE){ if(PeekMessage(&msg,NULL,0,0,PM_REMOVE)){ if(msg.message==WM_QUIT) break; TranslateMessage(&msg); DispatchMessage(&msg); }else{ //其他的一些事 } }
#include <windows.h> #include <stdlib.h> // for the rand function #include<ctime> LRESULT CALLBACK WndProc (HWND, UINT, WPARAM, LPARAM) ; void DrawRectangle (HWND) ; int cxClient, cyClient ; int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance, PSTR szCmdLine, int iCmdShow) { static TCHAR szAppName[] = TEXT ("RandRect") ; 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 ("Random Rectangles"), WS_OVERLAPPEDWINDOW, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, NULL, NULL, hInstance, NULL) ; ShowWindow (hwnd, iCmdShow) ; UpdateWindow (hwnd) ; while (TRUE) { if (PeekMessage (&msg, NULL, 0, 0, PM_REMOVE))//有消息返回真,无消息返回假 { if (msg.message == WM_QUIT) break ; TranslateMessage (&msg) ; DispatchMessage (&msg) ; } else DrawRectangle (hwnd) ; } return msg.wParam ; } LRESULT CALLBACK WndProc (HWND hwnd, UINT iMsg, WPARAM wParam, LPARAM lParam) { switch (iMsg)//这里没有WM_PAINT,因为wm_paint一直在循环,使得PeekMessage产生TRUE,从而调用不了DrawRetangle函数 { case WM_SIZE: cxClient = LOWORD (lParam) ; cyClient = HIWORD (lParam) ; srand(unsgined(time(NULL))) ;//随机数的种子 return 0; case WM_DESTROY: PostQuitMessage (0) ; return 0 ; } return DefWindowProc (hwnd, iMsg, wParam, lParam) ; } void DrawRectangle (HWND hwnd) { HBRUSH hBrush ; HDC hdc ; RECT rect ; if (cxClient == 0 || cyClient == 0) return ; SetRect (&rect, rand () % cxClient, rand () % cyClient, rand () % cxClient, rand () % cyClient) ;//随机产生不超过窗口大小的矩形 hBrush = CreateSolidBrush ( RGB (rand () % 256, rand () % 256, rand () % 256)) ;//随机产生画刷并填充刚刚产生的矩形 hdc = GetDC (hwnd) ; FillRect (hdc, &rect, hBrush) ; ReleaseDC (hwnd, hdc) ; DeleteObject (hBrush) ; }
效果极佳,可以作为屏保了。