程序8-5 WHATCLR
WHATCLR.C /*-------------------------------------------------------------------------- WHATCLR.C -- Displays Color Under Cursor (c) Charles Petzold, 1998 ---------------------------------------------------------------------------*/ #include <windows.h> #define ID_TIMER 1 void FindWindowSize (int *, int *) ; LRESULT CALLBACK WndProc (HWND, UINT, WPARAM, LPARAM) ; int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance, PSTR szCmdLine, int iCmdShow) { static TCHAR szAppName[] = TEXT ("WhatClr") ; HWND hwnd ; int cxWindow, cyWindow ; 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 ; } FindWindowSize (&cxWindow, &cyWindow) ; hwnd = CreateWindow (szAppName, TEXT ("What Color"), WS_OVERLAPPED | WS_CAPTION | WS_SYSMENU | WS_BORDER, CW_USEDEFAULT, CW_USEDEFAULT, cxWindow, cyWindow, NULL, NULL, hInstance, NULL) ; ShowWindow (hwnd, iCmdShow) ; UpdateWindow (hwnd) ; while (GetMessage (&msg, NULL, 0, 0)) { TranslateMessage (&msg) ; DispatchMessage (&msg) ; } return msg.wParam ; } void FindWindowSize (int * pcxWindow, int * pcyWindow) { HDC hdcScreen ; TEXTMETRIC tm ; hdcScreen = CreateIC (TEXT ("DISPLAY"), NULL, NULL, NULL) ; GetTextMetrics (hdcScreen, &tm) ; DeleteDC (hdcScreen) ; * pcxWindow = 2 * GetSystemMetrics (SM_CXBORDER) + 12 * tm.tmAveCharWidth ; * pcyWindow = 2 * GetSystemMetrics (SM_CYBORDER) + GetSystemMetrics (SM_CYCAPTION) + 2 * tm.tmHeight ; } LRESULT CALLBACK WndProc (HWND hwnd, UINT message, WPARAM wParam,LPARAM lParam) { static COLORREF cr, crLast ; static HDC hdcScreen ; HDC hdc ; PAINTSTRUCT ps ; POINT pt ; RECT rc ; TCHAR szBuffer [16] ; switch (message) { case WM_CREATE: hdcScreen = CreateDC (TEXT ("DISPLAY"), NULL, NULL, NULL) ; SetTimer (hwnd, ID_TIMER, 100, NULL) ; return 0 ; case WM_TIMER: GetCursorPos (&pt) ; cr = GetPixel (hdcScreen, pt.x, pt.y) ; SetPixel (hdcScreen, pt.x, pt.y, 0) ; if (cr != crLast) { crLast = cr ; InvalidateRect (hwnd, NULL, FALSE) ; } return 0 ; case WM_PAINT: hdc = BeginPaint (hwnd, &ps) ; GetClientRect (hwnd, &rc) ; wsprintf (szBuffer, TEXT (" %02X %02X %02X "), GetRValue (cr), GetGValue (cr), GetBValue (cr)) ; DrawText (hdc, szBuffer, -1, &rc, DT_SINGLELINE | DT_CENTER | DT_VCENTER) ; EndPaint (hwnd, &ps) ; return 0 ; case WM_DESTROY: DeleteDC (hdcScreen) ; KillTimer (hwnd, ID_TIMER) ; PostQuitMessage (0) ; return 0 ; } return DefWindowProc (hwnd, message, wParam, lParam) ; }