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<DIV>Hi Thorsten,<BR><BR>That's really helpful. I don't quite know how to write
out the number of bits as a char? If you could explain a way of how to do that
it would be greatly appreciated. <BR><BR>Also, how do I calculate what value
goes in for the offset? I had a look at a couple of output files from paraview
and it wasnt obvious how it was calculated.<BR><BR>Thanks<BR>David</DIV>
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<DIV><BR></DIV>
<DIV style="BACKGROUND: #f5f5f5">
<DIV style="font-color: black"><B>From:</B> <A title=th@tp1.rub.de
href="mailto:th@tp1.rub.de">Thorsten Hater</A> </DIV>
<DIV><B>Sent:</B> Tuesday, March 31, 2009 2:23 PM</DIV>
<DIV><B>To:</B> <A title=d.t.mulholland@googlemail.com
href="mailto:d.t.mulholland@googlemail.com">David Mulholland</A> </DIV>
<DIV><B>Cc:</B> <A title=paraview@paraview.org
href="mailto:paraview@paraview.org">paraview@paraview.org</A> </DIV>
<DIV><B>Subject:</B> Re: [Paraview] VTK XML Binary Output</DIV></DIV></DIV>
<DIV><BR></DIV>Hello,<BR><BR>the solution might be to append your data
as<BR><BR>< DataArray ... format="appended"><BR></DataArray><BR><
AppendedData encoding="raw"><BR>_NNNNData <BR></AppendedData><BR>where
you should replace NNNN with a four <BR>byte integer containing the number of
bytes <BR>in the data array as 4 chars.<BR>Setting the encoding to "raw" tells
ParaView, that<BR>the data is simply a stream of bytes rather than <BR>base64
encoded.<BR>If you want to write Image I can supply a small<BR>writer project
for 2D data.<BR><BR> Thorsten<BR> <BR>David Mulholland
schrieb:
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<DIV>Hello,<BR><BR>I am currently trying to write my own quick output routine
to generate a <BR>binary file using C++. I am currently trying to avoid having
to use the vtk <BR>libraries because I only need a very basic output that
doesn't change much. <BR>I so far have the ASCII output working no problem but
I can't get the binary <BR>working.<BR><BR>I am using file.write() function to
output the binary data and that seems to <BR>be working no problem and when
used in a legacy format application it works <BR>perfectly except that the
data is LittleEndian instead of BigEndian. That's <BR>why I have moved to
BigEndian because I don't want to have to make the <BR>output routine for the
data anymore complicated that file.write.<BR><BR>I started using the xml
format and considering my output is raw binary and <BR>not base64 I changed it
to be in the AppendedData section instead of <BR>DataArray. It still isn't
working right, I get the following error when I <BR>try to load in
ParaView:<BR><BR>ERROR: In
..\..\..\ParaView3\VTK\IO\vtkXMLStructuredDataReader.cxx, line
349<BR>vtkXMLImageDataReader (0ADEC7F8): Error reading extent 0 422 0 242 0 1
from <BR>piece 0<BR><BR><BR>ERROR: In
..\..\..\ParaView3\VTK\IO\vtkXMLDataReader.cxx, line
537<BR>vtkXMLImageDataReader (0ADEC7F8): Cannot read cell data array
"pressure" <BR>from PointData in piece 0. The data array in the element
may be too short.<BR><BR>The format of my output file is as
follows:<BR><BR><?xml version="1.0"?><BR><VTKFile type="ImageData"
version="0.1" byte_order="LittleEndian"><BR><ImageData WholeExtent="0
422 0 242 0 1" Origin="0 0 0" Spacing="1 1 1"><BR><Piece Extent="0 422 0
242 0 1"><BR><PointData><BR></PointData><BR><CellData
Scalars="pressure"><BR><DataArray type="Float32" Name="pressure"
format="appended"
offset="0"/><BR></CellData><BR></Piece><BR></ImageData><BR><AppendedData
encoding="raw"><BR>_BINARYDATA<BR></AppendedData><BR></VTKFile><BR><BR>Note
following an error message I have added an _ at the start of the binary
<BR>data. Is this required?<BR><BR>One final thing, when using appended data,
how do you calculate what the <BR>offset should
be?<BR><BR>Thanks<BR>David</DIV><PRE wrap=""><HR SIZE=4 width="90%">
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