Knowledge Base Nr: 00298 scrollzoom.cpp - http://www.swe-kaiser.de

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MFC: VS2005 Scaling in ScrollView mit mapping mode != MM_xxxISOTROPIC (z.b. MM_LOMETRIC, MM_HIMETRIC, ...)

  
- in h-file von view definieren
  float fScale;
  float fOldScale;
  float Scale(float v) { return fScale*v; }

- initialisieren in OnInitialUpdate() oder Konstruktor
  fScale = 1.2;

- messagehandler für zoom-faktor

void ClulliView::OnZoomZoomin()
{
  fScale += 0.2;
  if (fScale > 3.0)
    fScale = 3.0;
	Invalidate();
	UpdateWindow();
	RedrawWindow();
}

void ClulliView::OnZoomZoomout()
{
  fScale -= 0.2;
  if (fScale < 0.2)
    fScale = 0.2;
	Invalidate();
	UpdateWindow();
	RedrawWindow();
}

- drucken korrigieren (ohne zoom)
void ClulliView::OnBeginPrinting(CDC* /*pDC*/, CPrintInfo* /*pInfo*/)
{
  fOldScale = fScale;
  fScale = 1;
}

void ClulliView::OnEndPrinting(CDC* /*pDC*/, CPrintInfo* /*pInfo*/)
{
  fScale = fOldScale;
}

- scalierung beim zeichnen berücksichtigen
void ClulliView::OnDraw(CDC* pDC)
{
...
	//font
  CFont cfNew;
  LOGFONT lf;
  CFont* cfOld;

  memset(&lf, 0, sizeof(LOGFONT));
  lf.lfHeight = Scale(30);
	wcscpy(lf.lfFaceName, CString("Arial"));
  cfNew.CreateFontIndirect(&lf);

  cfOld = pDC->SelectObject(&cfNew);

	//seitengröße beim zoomen anpassen
  CSize sizeTotal;
  sizeTotal.cx = Scale(2100);
  sizeTotal.cy = Scale(2900);
  SetScrollSizes(MM_LOMETRIC, sizeTotal); //nicht möglich mit MM_ISOTROPIC!!!

  CString str;

  int x = -200;
  int y = -200;
  str.Format(CString("Zoom: %.2f - SetWindowOrg(%d/%d)"), fScale, x, y);
  pDC->TextOut(Scale(500), Scale(-2800),str, str.GetLength());

  //pDC->ScaleWindowExt(xNum, xDenom, yNum, yDenom);  //keine auswirkung mapping mode MM_LOMETRIC!!!

  //SetWindowExtEx() nicht mapping mode MM_LOMETRIC!!!
  pDC->SetWindowOrg(Scale(x), Scale(y));

  for (int i=0; i<30; i++)
  {
    x = Scale(i*50);
    y = Scale(-2900 + i*50);
    str.Format(CString("%d/%d lulli lulli"), x, y);
    pDC->TextOut(x, y,str, str.GetLength());

    pDC->MoveTo(0, 0);
    pDC->LineTo(x, 0);
    pDC->LineTo(x, y);
    pDC->LineTo(0, y);
    pDC->LineTo(0, 0);
  }

  pDC->SelectObject(cfOld);
  cfNew.DeleteObject();
}