[cad-linux] Re: Command line DWG to DXF converter

A couple of items to further this discussion.

1)  The conversion from dwg to dxf is accomplished using functions which are 
part of the OD toolkit library.  All that is required for this conversion is 
to call the proper functions.   The other conversions (for instance to bmp or 
xpm) require that the data contained in the drawing file be vectorized first. 
 In my drawing viewer program these last two conversions are done using built 
in functions in QT (basically snap shots of the contents of the view window). 
 

2)  Vectorizing the data to screen or printer is relatively simple (provided 
you have the right drivers or tool kits), but a couple of design issues will 
need to be worked out for a command line program.  Specifically how to search 
for SHX and XREF files, and what action to take if they are not found.  The 
first part is easy, but the last is subject to user preferences.  I do all 
right with computers, but put people into the mix and things tend to get 
messy.

3)  Since a command line program would only be able to print the last saved 
view could you not achieve the same result by just extracting the bitmap 
image stored with the file and then saving it as a new bmp file?  This of 
course would only work with newer drawing files (I believe R13 and above).

4)  After your post I spent some time looking at web sites for Ghostscript 
and Adobe.  It appears that it would be possible to write a program to export 
a picture of a drawing to other formats, but it would require some time to 
become familiar with the file format.  I also looked at DWF but ACAD does not 
seem to want anyone to write their own versions of a viewer for this format.  
You can down load free plug-ins all you want, but don't ask for the technical 
details of the file format.

Anyway - just a couple of things to ponder.

Andy

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