here is some code from petzold to illustrate what you need to do.....
Code:
#include <windows.h>
#include <math.h>
#define NUM 1000
#define TWOPI (2*3.14159)
LRESULT CALLBACK WndProc(HWND,UINT,WPARAM,LPARAM);
int WINAPI WinMain(HINSTANCE hInstance,HINSTANCE hPrevInstance,PSTR szCmdLine,int iCmdShow)
{
static TCHAR szAppName[]=TEXT("SineWave");
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("Sine wave using polyline function!"),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 int cxClient,cyClient;
HDC hdc;
int i;
PAINTSTRUCT ps;
POINT apt[NUM];
switch(message)
{
case WM_SIZE:
cxClient=LOWORD(lParam);
cyClient=HIWORD(lParam);
return 0;
case WM_DESTROY:
PostQuitMessage(0);
return 0;
case WM_PAINT:
hdc=BeginPaint(hwnd,&ps);
MoveToEx(hdc,0,cyClient/2,NULL);
LineTo(hdc,cxClient,cyClient/2);
for (i=0;i<NUM;i++)
{
apt[i].x=i*cxClient/NUM;
apt[i].y=(int) (cyClient/2*(1-sin(TWOPI*i/NUM)));
}
Polyline(hdc,apt,NUM);
return 0;
}
return DefWindowProc(hwnd,message,wParam,lParam);
}