윈도우 API 예제

#include <windows.h>

LRESULT CALLBACK WndProc(HWND,UINT,WPARAM,LPARAM);
HINSTANCE g_hInst;
LPSTR lpszClass="Mouse";

int APIENTRY WinMain(HINSTANCE hInstance,HINSTANCE hPrevInstance
   ,LPSTR lpszCmdParam,int nCmdShow)
{
HWND hWnd;
MSG Message;
WNDCLASS WndClass;
g_hInst=hInstance;

WndClass.cbClsExtra=0;
WndClass.cbWndExtra=0;
WndClass.hbrBackground=(HBRUSH)GetStockObject(WHITE_BRUSH);
WndClass.hCursor=LoadCursor(NULL,IDC_ARROW);
WndClass.hIcon=LoadIcon(NULL,IDI_APPLICATION);
WndClass.hInstance=hInstance;
WndClass.lpfnWndProc=(WNDPROC)WndProc;
WndClass.lpszClassName=lpszClass;
WndClass.lpszMenuName=NULL;
WndClass.style=CS_HREDRAW | CS_VREDRAW | CS_DBLCLKS;
RegisterClass(&WndClass);

hWnd=CreateWindow(lpszClass,lpszClass,WS_OVERLAPPEDWINDOW,
   CW_USEDEFAULT,CW_USEDEFAULT,CW_USEDEFAULT,CW_USEDEFAULT,
   NULL,(HMENU)NULL,hInstance,NULL);
ShowWindow(hWnd,nCmdShow);

while(GetMessage(&Message,0,0,0)) {
 TranslateMessage(&Message);
 DispatchMessage(&Message);
}
return Message.wParam;
}

LRESULT CALLBACK WndProc(HWND hWnd,UINT iMessage,WPARAM wParam,LPARAM lParam)
{
HDC hdc;
static int x;
static int y;
static BOOL bnowDraw=FALSE;
switch(iMessage) {
case WM_LBUTTONDOWN:
 x=LOWORD(lParam);
 y=HIWORD(lParam);
 bnowDraw=TRUE;
 return 0;
case WM_MOUSEMOVE:
 if (bnowDraw==TRUE) {
  hdc=GetDC(hWnd);
  MoveToEx(hdc,x,y,NULL);
  x=LOWORD(lParam);
  y=HIWORD(lParam);
  LineTo(hdc,x,y);
  ReleaseDC(hWnd,hdc);
 }
 return 0;
case WM_LBUTTONUP:
 bnowDraw=FALSE;
 return 0;

case WM_LBUTTONDBLCLK:
 InvalidateRect(hWnd, NULL, TRUE);
 return 0;
case WM_DESTROY:
 PostQuitMessage(0);
 return 0;
}
return(DefWindowProc(hWnd,iMessage,wParam,lParam));
}