#include <windows.h>
#include <tchar.h>
#include <math.h>

#define MAXLENTH 100

LRESULT CALLBACK WndProc (HWND, UINT, WPARAM, LPARAM) ;
ATOM MyRegisterClass(HINSTANCE hInstance);

TCHAR szAppName[] = _TEXT("Graphic");
TCHAR szTitleMain[MAXLENTH];
int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance, PSTR szCmdLine, int iCmdShow)
{
	HWND hWndMain;
	MSG msg;


	if(!MyRegisterClass(hInstance))
	{
		//MessageBox(hWnd,_TEXT("Can't register class"),_TEXT("Error..."), MB_OK | MB_ICONINFORMATION);
	}
	LoadString(hInstance,101,szTitleMain,MAXLENTH);
	hWndMain = CreateWindow(szAppName,szTitleMain,WS_OVERLAPPEDWINDOW,
							CW_USEDEFAULT,CW_USEDEFAULT,
							CW_USEDEFAULT,CW_USEDEFAULT,NULL,NULL,
							hInstance,NULL);
	ShowWindow(hWndMain, iCmdShow);
	UpdateWindow(hWndMain);

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

ATOM MyRegisterClass(HINSTANCE hInstance)
{
	WNDCLASSEX wcex;
	wcex.cbSize = sizeof(WNDCLASSEX);
	wcex.cbClsExtra	= 0;
	wcex.cbWndExtra = 0;
	wcex.style = CS_VREDRAW | CS_HREDRAW;
	wcex.lpfnWndProc = WndProc;
	wcex.hInstance = hInstance;
	wcex.hCursor = LoadCursor(NULL,IDC_ARROW);
	wcex.hIcon = LoadIcon(NULL,IDI_QUESTION);
	wcex.hbrBackground = (HBRUSH)(COLOR_BTNFACE+1);
	wcex.lpszMenuName = NULL; // Пока не используем
	wcex.hIconSm = LoadIcon(NULL,IDI_QUESTION);
	wcex.lpszClassName = szAppName;
	return RegisterClassEx(&wcex);
}					

float fn(float x)
{
	return 3*x-cos(x) - 1;
}

LRESULT CALLBACK WndProc (HWND hWnd, UINT iMsg, WPARAM wParam, LPARAM lParam)
{
	HDC hDC;
	PAINTSTRUCT ps;
	RECT rect;
	static int draw_graf;
	static int clx,cly,mx=20,my=20;
	switch(iMsg)
	{
	case WM_CREATE:
		draw_graf = 1;
		return 0;
	case WM_SIZE:
		clx = LOWORD(lParam);
		cly = HIWORD(lParam);
	case WM_PAINT:
		hDC = BeginPaint(hWnd,&ps);
		GetClientRect(hWnd,&rect);
		
		if(draw_graf)
		{MoveToEx(hDC,0,cly/2,NULL);
        LineTo(hDC,clx,cly/2);
        LineTo(hDC,clx-5,(cly/2)-5);
        MoveToEx(hDC,clx,cly/2,NULL);
        LineTo(hDC,clx-5,(cly/2)+5);

        MoveToEx(hDC,clx/2,cly,NULL);
        LineTo(hDC,clx/2,0);
        LineTo(hDC,(clx/2)-5,5);
        MoveToEx(hDC,(clx/2)+5-1,5-1,NULL);
        LineTo(hDC,clx/2,0);

			for(int i=0;i<clx;i++)
				SetPixel(hDC,i,(cly/2)-my*fn((float)i/mx),RGB(255,50,9));
		}
		EndPaint(hWnd,&ps);
		return 0;
	case WM_LBUTTONDOWN:
		if(mx<256)
		{
			mx*=2;
			my=mx;
			draw_graf=1;
			InvalidateRect(hWnd,NULL,true);
		}
		return 0;
	case WM_RBUTTONDOWN:
		if(mx>32)
		{
			mx/=2;
			my=mx;
			draw_graf=1;
			InvalidateRect(hWnd,NULL,true);
		}
		return 0;
	case WM_DESTROY:
		PostQuitMessage(0);
		return 0;
	}
	return DefWindowProc(hWnd,iMsg,wParam,lParam);
}