Code:
#include <windows.h>
#include <winuser.h>
#define ID_TIMER 1
LRESULT CALLBACK WndProc (HWND, UINT, WPARAM, LPARAM) ;
void DrawRectangle (HWND) ;
void DrawEllipse (HWND) ;
int cxClient, cyClient ;
int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance,
PSTR szCmdLine, int iCmdShow)
{
static TCHAR szAppName[] = TEXT ("Beeper1") ;
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 ("Program requires Windows NT!"),
szAppName, MB_ICONERROR) ;
return 0 ;
}
hwnd = CreateWindow (szAppName, TEXT ("Beeper1 Timer 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)
{
HBRUSH hBrush ;
HDC hdc ;
PAINTSTRUCT ps ;
RECT rc ;
switch (message)
{
case WM_SIZE:
cxClient = LOWORD (lParam) ;
cyClient = HIWORD (lParam) ;
return 0 ;
case WM_CREATE:
SetTimer (hwnd, ID_TIMER, 2000, NULL) ;
return 0 ;
case WM_TIMER :
InvalidateRect (hwnd, NULL, FALSE) ;
return 0 ;
case WM_PAINT :
hdc = BeginPaint (hwnd, &ps) ;
GetClientRect (hwnd, &rc) ;
hBrush = CreateSolidBrush (RGB(0,0,0)) ;
FillRect (hdc, &rc, hBrush) ;
DrawEllipse (hwnd) ;
EndPaint (hwnd, &ps) ;
DeleteObject (hBrush) ;
return 0 ;
case WM_DESTROY :
KillTimer (hwnd, ID_TIMER) ;
PostQuitMessage (0) ;
return 0 ;
}
return DefWindowProc (hwnd, message, wParam, lParam) ;
}
void DrawEllipse (HWND hwnd)
{
HBRUSH hBrush ;
HDC hdc = NULL;
PAINTSTRUCT ps;
hdc= BeginPaint(hwnd, &ps);
if (cxClient == 0 || cyClient == 0)
return ;
Ellipse (hdc,rand () % cxClient, rand () % cyClient,
rand () % cxClient, rand () % cyClient) ;
hBrush = CreateSolidBrush (RGB (rand () % 256, rand () % 256, rand () % 256)) ;
hdc = GetDC (hwnd) ;
FillEllipse (hBrush,Ellipse) ;
ReleaseDC (hwnd, hdc) ;
DeleteObject (hBrush) ;
}