KGLab2

void paintFunction(HWND *hWnd, int sx, int sy)
{
    PAINTSTRUCT ps;
    HDC hdc = BeginPaint(*hWnd, &ps);

    HPEN hpen1=CreatePen(PS_SOLID,2,RGB(0,0,255));
    HPEN hpen2=CreatePen(PS_SOLID,2,RGB(255,0,0));

    //Êîîðäèíàòû öåíòðà
    int a = sx / 2;
    int b = sy / 2;

    SelectObject(hdc, hpen1);

    MoveToEx(hdc, 0, b, NULL);
    LineTo(hdc, sx, b);

    MoveToEx(hdc, a, 0, NULL);
    LineTo(hdc, a, sy);

    for(double x = 0; x < sx; x += 10)
    {
        MoveToEx(hdc, x, b + 5, NULL);
        LineTo(hdc, x, b - 5);
    }

    for(double y = 0; y < sy; y += 10)
    {
        MoveToEx(hdc, a - 5, y, NULL);
        LineTo(hdc, a + 5, y);
    }

    SelectObject(hdc, hpen2);
    MoveToEx(hdc, 0, b, NULL);

    double h = 3 * M_PI / a;
    for(double x = -M_PI, x_scr = 0; x < M_PI; x += h)
    {
        x_scr = (x + M_PI) * a / M_PI;
        double y_scr = b - b * 5 * pow(x,2) - 7;
        LineTo(hdc, x_scr, y_scr);
    }
    EndPaint(*hWnd, &ps);
}