用OBJECTARX如何获得模型空间的VIEWPORT信息的方法。

XDSoft

GETTING CURRENT MODEL SPACE VIEWPORT INFO WITH OBJECTARX
Product AUTOCAD  Author WHITLEY,RICHARD
Date 28-AUG-97  Document ID 1698
Expiration date    Attachments  
Keywords ARX

Developer Consulting Group technical solution. Autodesk confidential, for ADN members only. Please read the disclaimer

Question


In Paper Space there is a function AcDbGetCurViewportId, which returns the
current viewport object ID. How can I determine the current viewport and its
status when tilemode = 1?


Answer


Model Space viewports are of type AcDbViewportTableRecord, as compared to
AcDbViewport entities in Paper Space. To get the Model Space viewport table
records you can use an AcDbViewportTableIterator. However, there is no easy
ARX method for finding out which is the currently selected viewport if your
setup has multiple viewports. The "active" viewports (those currently
displaying in Model Space) will all have the name "*ACTIVE". Although the
Reference Manual states that the first *ACTIVE in the table will always be
the current viewport, this does not always happen in real life.  Also, if the
viewport configuration has been altered during the current drawing session,
the iterator will not report the new information until the drawing has been
saved.

Therefore, the most reliable method at this time is still ads_getvar. The
system variables are always in sync with the current viewport. The CVPORTS
system variable returns the model space index for the current viewport;
however, this value is not used by ARX member functions. You can also check
GRIDMODE, GRIDUNIT, SNAPANG, SNAPBASE, UCSICON, UCSFOLLOW and the VIEW*
system variables to get detailed information about the current viewport.


Disclaimer

This information is derived from a response to a specific question sent to the Developer Consulting Group at Autodesk, and thus given its nature, is subject to change without notice. The information is provided to you on an "as is" basis, and you may use it only at your own risk. Autodesk is not responsible for its quality, nor shall it be liable for any damage or loss caused by your use of this information.

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