Add binary new-lines to VTK export. (#795)

Fix VTK output: add newlines after binary data blocks to ensure compatibility with meshio.
evalf · May 19, 2023 · c471750 · c471750
2 parents 8d1e969 + 0170613
commit c471750
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Showing 2 changed files with 11 additions and 3 deletions.
diff --git a/nutils/export.py b/nutils/export.py
@@ -182,14 +182,18 @@ def vtkarray(a):  # convert to big endian data and zero-pad all axes to length 3
         vtk.write(b'# vtk DataFile Version 3.0\nvtk output\nBINARY\nDATASET UNSTRUCTURED_GRID\n')
         vtk.write('POINTS {} {}\n'.format(npoints, vtkdtype[points.dtype]).encode('ascii'))
         points.tofile(vtk)
+        vtk.write(b"\n")
         vtk.write('CELLS {} {}\n'.format(ncells, t_cells.size).encode('ascii'))
         t_cells.tofile(vtk)
+        vtk.write(b"\n")
         vtk.write('CELL_TYPES {}\n'.format(ncells).encode('ascii'))
         vtkcelltype[nverts].repeat(ncells).tofile(vtk)
+        vtk.write(b"\n")
         for n, items in gathered:
             vtk.write('{}_DATA {}\n'.format('POINT' if n == npoints else 'CELL', n).encode('ascii'))
             for dname, array in items:
                 vtk.write(vtkndim[array.ndim].format(dname, vtkdtype[array.dtype]).encode('ascii'))
                 array.tofile(vtk)
+                vtk.write(b"\n")
 
 # vim:sw=4:sts=4:et
diff --git a/tests/test_export.py b/tests/test_export.py
@@ -77,23 +77,25 @@ def data(self):
             yield bytes([0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 63, 128, 0, 0, 0, 0, 0, 0, 63, 128, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 63, 128, 0, 0])
         else:
             raise Exception('not supported: xtype={!r}, ndims={}'.format(self.xtype, self.ndims))
+        yield b'\n'
         if self.ndims == 1:
             yield b'CELLS 3 9\n'
             yield bytes([0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 2, 0, 0, 0, 1, 0, 0, 0, 2, 0, 0, 0, 2, 0, 0, 0, 2, 0, 0, 0, 3])
-            yield b'CELL_TYPES 3\n'
+            yield b'\nCELL_TYPES 3\n'
             yield bytes([0, 0, 0, 3, 0, 0, 0, 3, 0, 0, 0, 3])
         elif self.ndims == 2:
             yield b'CELLS 2 8\n'
             yield bytes([0, 0, 0, 3, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 2, 0, 0, 0, 3, 0, 0, 0, 1, 0, 0, 0, 2, 0, 0, 0, 3])
-            yield b'CELL_TYPES 2\n'
+            yield b'\nCELL_TYPES 2\n'
             yield bytes([0, 0, 0, 5, 0, 0, 0, 5])
         elif self.ndims == 3:
             yield b'CELLS 1 5\n'
             yield bytes([0, 0, 0, 4, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 2, 0, 0, 0, 3])
-            yield b'CELL_TYPES 1'
+            yield b'\nCELL_TYPES 1'
             yield bytes([10, 0, 0, 0, 10])
         else:
             raise Exception('invalid ndims {}'.format(self.ndims))
+        yield b'\n'
         if self.p is not None:
             yield b'POINT_DATA 4\n'
             if self.ptype == 'f4' and self.pshape == ():
@@ -128,13 +130,15 @@ def data(self):
                 yield bytes([0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35])
             else:
                 raise Exception('not supported: ptype={}, udims={}'.format(self.ptype, self.udims))
+            yield b'\n'
         if self.c is not None:
             yield b'CELL_DATA 1\n'
             if self.ndims == 3 and self.ctype == 'i1' and self.cshape == ():
                 yield b'SCALARS c char 1\nLOOKUP_TABLE default\n'
                 yield bytes([0])
             else:
                 raise Exception('not supported: ndims={}, ctype={}, cdims={}'.format(self.ndims, self.ctype, self.cdims))
+            yield b'\n'
 
     def test_data(self):
         with tempfile.TemporaryDirectory() as outdir, treelog.set(treelog.DataLog(outdir)):