[vtkusers] vtkXMLImageDataReader ProgressEvent

[Slobodan Miskovic]

> Don't do any multithreading thing. This very simple python script works with VTK CVS:
> 
> import vtk
> 
> reader = vtk.vtkDataSetReader()
> reader.SetFileName('foo.vtk')
> 
> def MyProc(object, event):
>   print "foo", reader.GetProgress()
> 
> reader.AddObserver("ProgressEvent", MyProc)
> reader.Update()
> 
> This should work the as well using the XML readers.

That is basically what what my C++ code does, but with a bit of
tracing around, this is a code from 4.2 xmlDataReader

function ReadCompressedData
...
    unsigned int currentBlock = firstBlock+1;
    for(;currentBlock != lastBlock; ++currentBlock)
      {
      if(!this->ReadBlock(currentBlock, outputPointer)) { return 0; }
      outputPointer += this->FindBlockSize(currentBlock);
      }
...

Obviously it dooesn't update progress anywhere. For comparison, this
is the latest CVS code (minus the comments):

    unsigned int currentBlock = firstBlock+1;
    for(;currentBlock != lastBlock && !this->Abort; ++currentBlock)
      {
      if(!this->ReadBlock(currentBlock, outputPointer)) { return 0; }
      this->PerformByteSwap(outputPointer, blockSize / wordSize, wordSize);
      outputPointer += this->FindBlockSize(currentBlock);

      this->UpdateProgress(float(outputPointer-data)/length);
      }


Lesson learned? I should stick with CVS :) Thanks to all (David,
Mathieu) who looked into this.

Slobo