[Paraview] writeing vts files

[Brad King]

don fisher wrote:
> I have examined the length of the appended data record and it is 34136, 
> the correct length to encode one floating scalar and a three component 
> float vector (dimensions 40X20X2). The output I receive from Paraview 
> consists of 3 occurrences of:
> ---------------------------------------------------------------------
> ErrorMessage
> # Error or warning: There was a VTK Error in file: 
> /usr3/swl/packages/ParaView/VTK/IO/vtkXMLStructuredDataReader.cxx (281)
>  Error reading extent 0 39 0 19 0 1 from piece 0
> ErrorMessage end
> ---------------------------------------------------------------------

The CVS version of these readers is currently undergoing some changes so 
this may be a bogus message, though it looks like a reasonable error if 
something is wrong with your appended data section.

> I have looked at the code, but it is not easy to read. The parse 
> routines are order 4500 lines long, with mangled names and large 
> #defines rather that inline functions. I does confuse my debugger. Any 
> help would be appreciated.

To what source files are you referring?

> The only example on the CD and distribution includes zlib compression. 
> Is that required, or is there another string required to say "no 
> compression".

If you leave off the "compressor" attribute from the top-level VTKData 
element then there is no compression.

 > I cannot find any details in the books or enclosed CD. The
> terms "binary" and "base64" seem to be overlapped.

The "binary" format means that the data are inlined inside the DataArray 
element.  Inlined data must be base64 encoded to keep the XML valid. 
The "appended" format means that the data are in the AppendedData 
element at the end of the file.  This element has its own "encoding" 
attribute which is usually base64.  As a hack to support fast reading we 
also allow the AppendedData section to be pure binary (not encoded), 
though this makes the document invalid XML.

-Brad