如何在CScrollView中实现MM_ISOTROPIC模式下图形（绘图）的滚动

Question

之前在贴上看到过以下的处理方式 但是我试了 不好使 有高手实现过的话请不吝指教，请将过程说清楚 [email protected]（我的邮箱) 
从CScroolView类继承，   
  在OnPrepareDC中这样写:   
    
  pDC->SetMapMode(MM_ISOTROPIC);   
  pDC->SetWindowOrg((int)(-m_fXOrg*1000),(int)(m_fYOrg*1000));   
  pDC->SetWindowExt(1000,-1000);   
  pDC->SetViewportExt(1,1);

Answer 1

void CXXXView::OnPrepareDC(CDC* pDC, CPrintInfo* pInfo)
{
CScrollView::OnPrepareDC(pDC, pInfo); // mapping mode is MM_ANISOTROPIC
// these extents setup a mode similar to MM_LOENGLISH
// MM_LOENGLISH is in .01 physical inches
// these extents provide .01 logical inches pDC->SetMapMode(MM_ANISOTROPIC);
pDC->SetWindowExt(100, -100);
pDC->SetViewportExt(pDC->GetDeviceCaps(LOGPIXELSX),pDC->GetDeviceCaps(LOGPIXELSY)); // set the origin of the coordinate system to the center of the page
CPoint ptOrg;
ptOrg.x = GetDocument()->GetSize().cx / 2;
ptOrg.y = GetDocument()->GetSize().cy / 2; // ptOrg is in logical coordinates
pDC->OffsetWindowOrg(-ptOrg.x,ptOrg.y);
}void CXXXView::OnDraw(CDC* pDC)
{
CDrawEleDoc* pDoc = GetDocument();
ASSERT_VALID(pDoc); CDC dc;
CDC* pDrawDC = pDC;
CBitmap bitmap;
CBitmap* pOldBitmap = 0; // only paint the rect that needs repainting
CRect client;
pDC->GetClipBox(client);
CRect rect = client;
DocToClient(rect); if (!pDC->IsPrinting())
{
// draw to offscreen bitmap for fast looking repaints
if (dc.CreateCompatibleDC(pDC))
{
if (bitmap.CreateCompatibleBitmap(pDC, rect.Width(), rect.Height()))
{
OnPrepareDC(&dc, NULL);
pDrawDC = &dc; // offset origin more because bitmap is just piece of the whole drawing
dc.OffsetViewportOrg(-rect.left, -rect.top);
pOldBitmap = dc.SelectObject(&bitmap);
dc.SetBrushOrg(rect.left % 8, rect.top % 8); // might as well clip to the same rectangle
dc.IntersectClipRect(client);
}
}
} // paint background
CBrush brush;
if (!brush.CreateSolidBrush(pDoc->GetPaperColor()))
return; brush.UnrealizeObject();
pDrawDC->FillRect(client, &brush); ////////////////////////
CBrush brush1;
if (!brush1.CreateSolidBrush(pDoc->GetPaperColor()))
return;
CRect rect1;
rect1.left = -pDoc->GetSize().cx / 2;
rect1.top = -pDoc->GetSize().cy / 2;
rect1.right = rect1.left + pDoc->GetSize().cx;
rect1.bottom = rect1.top + pDoc->GetSize().cy; brush1.UnrealizeObject(); pDrawDC->FillRect(rect1, &brush1); ////////////////////////绘制你真正要绘制的内容
pDoc->Draw(pDrawDC, this);
         ///end if (pDrawDC != pDC)
{
pDC->SetViewportOrg(0, 0);
pDC->SetWindowOrg(0,0);
pDC->SetMapMode(MM_TEXT);
dc.SetViewportOrg(0, 0);
dc.SetWindowOrg(0,0);
dc.SetMapMode(MM_TEXT);
pDC->BitBlt(rect.left, rect.top, rect.Width(), rect.Height(),
&dc, 0, 0, SRCCOPY);
dc.SelectObject(pOldBitmap);
}}

Answer 2

GetDocument()->GetSize() 
出错：
Doc类没有GetSize这个成员函数