Preview and Clipping Regions Coordinates

I'm using regions for clipping graphics in printouts like:
      CRgn rgn;  ...  pDC->SelectClipRgn(&rgn);
This works fine only for the real print, not for the screen-preview. It seems that SelectClipRgn needs the real screen-coordinates instead of the printer-coordinates for correct clipping in preview-mode ?!
How can I transform the preview printer coordinates in real screen-coordinates? This should also be usefull for calculating the paper position for mouse clicks on the preview screen..   Thorsten
BTW: ScreenToClient and ClientToScreen doesn't solve the problem?!
todiAsked:
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byangCommented:
If your coordinates is in real-world unit, like mm or inch, then just set the apppropriate mapping mode at preview time.

If your coordinates are in printer device unit, then you need to write code to convert coordinates at preview time.

Or you can setup a mapping mode using SetMapMode(,MM_ANISOTROPIC), SetWindowExtEx, and SetViewportExtEx.
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todiAuthor Commented:
Thanks for your answer!
Before I read your answer, I tried coordinates in printer device units, and I didn't convert them to screen coordinates. So my clipping region only works on the printer, not at preview time.

-> How can I convert them at preview time? <-

I changed the mapping mode to "mm_lometric" but the clipping was only correct on the printer. I think I've done it right?!
Is there really an internal routine converting the printer coordinates for the preview in screen-coordinates, or does "pDC->SetClipRgn" needs screen coordinates everytime, not depending on the mapping mode?

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