[RESOLVED] Coordinate problem (an image attached)

I want to reuse DrawPie function to draw 4 same pies, but it was unexpected. I don't understand what have been happening.
I divide the client area by 4, then pass each rect to DrawPie.

I suspect setWindowOrigin or setViewportOrigin is needed.

application image: http://i240.photobucket.com/albums/f...214/post-1.jpg

Code:

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void CMainWindow::DrawPie(CDC *pDC, CRect &rect)
{
        // prepare to draw pie
        CBrush brush;
        brush.CreateHatchBrush(HS_BDIAGONAL, RGB(255, 0, 0));
        CBrush *pOldBrush = pDC->SelectObject(&brush);

        CPoint startPoint = rect.BottomRight();
        CPoint endPoint = rect.BottomRight();
        startPoint.y /= 2;
        endPoint.x /= 2;

        // draw pie
        pDC->Pie(&rect, startPoint, endPoint);

        pDC->SelectObject(pOldBrush);
}

void CMainWindow::OnPaint()
{
        CPaintDC dc(this);
        CRect rect;
        GetClientRect(&rect);       
       
       
        int leftCenter = rect.left / 2;
        int topCenter = rect.top / 2;
        int rightCenter = rect.right / 2;
        int bottomCenter = rect.bottom / 2;

        COLORREF clrColors[] = {RGB(100, 0, 0), RGB(0, 100, 0), RGB(0, 0, 100), RGB(100, 0, 100)};
        int widthIncrement = rect.right / 2;
        int heightIncrement = rect.bottom / 2;
        int k = 0;
        for(int i = 0; i < rect.bottom; i += heightIncrement)
                for(int j = 0; j < rect.right; j += widthIncrement)
                {
                        CPoint leftTop(j, i);
                        CPoint rightBottom(j + widthIncrement, i + heightIncrement);

                        CRect rect;
                        rect.TopLeft() = leftTop;
                        rect.BottomRight() = rightBottom;

                        CBrush brush;
                        brush.CreateSolidBrush(clrColors[k++]);
                        CBrush *pOldBrush = dc.SelectObject(&brush);
                        dc.Rectangle(rect);

                        DrawPie(&dc, rect);
                        dc.SelectObject(pOldBrush);
                }       
}

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Thank you

After debugging, I found that my startPoint and my endPoint are wrong. Marked as resolved.