mfc相对任意点错切

我在用vc6.0++mfc工程做图形学，这个相对任意点错切的函数，实现时并没有相对某个点移动，还是在原来的位置，不知道哪里写错了

void CTestView::OnSharex() //任意点错切
{
    // TODO: Add your command handler code here
    CDC *pDC = GetDC();
    CRect rectClient;
    GetClientRect(rectClient);
    pDC->SetMapMode(MM_ISOTROPIC);
    pDC->SetWindowExt(2000,1000);
    pDC->SetViewportExt(rectClient.right,-rectClient.bottom);
    pDC->SetViewportOrg(rectClient.right/2,rectClient.bottom/2);

    CPen MyPen,*OldPen; 
    int color = RGB(0,0,255);
    MyPen.CreatePen(PS_SOLID,3,color); 
    OldPen=pDC->SelectObject(&MyPen);

    double b,c;
    DialogShare dlg;
    if(dlg.DoModal())
    {
        b = dlg.m_b;
        c = dlg.m_c;
    }

    int x,y;
    DialogX dlg1;
    if(dlg1.DoModal())
    {
        x = dlg1.m_x*100;
        y = dlg1.m_y*100;
    }

    int i,t[6];
    for(i=0;i<6;i++)
    {
        if(i%2 == 0)
        {
            t[i] = n[i] + c*n[i+1]-y*c;
        }
        else
        {
            t[i] = b*n[i-1] + n[i]-b*x;
        }
    }
    double tx,ty;
    tx = ((n[0] + n[2] + n[4]) - (t[0] + t[2] + t[4]))/3;
    ty = ((n[1] + n[3] + n[5]) - (t[1] + t[3] + t[5]))/3;
    Tri(t[0]+tx,t[1]+ty,t[2]+tx,t[3]+ty,t[4]+tx,t[5]+ty,pDC);
    
}