[vtkusers] vtkImageReader and actual file access time

[Hamid]

Thanks for the quick respone...

So do you know which class is doing the exact reading, i.e., executing  
something like:

	streamPointer->get(ch);
	vtkImageData <- ch;

Thanks
Hamid

On Mon, 27 Sep 2004 14:26:39 +0530, <kalyan.pushpala at wipro.com> wrote:

>
> Hai
> As VTK follows lazy evaluation
> Veiwer->render() will intiare reader->Update() .At that point of time
> file will be readed
>
> kalyan
>
> -----Original Message-----
> From: vtkusers-bounces at vtk.org [mailto:vtkusers-bounces at vtk.org] On
> Behalf Of Hamid
> Sent: Monday, September 27, 2004 2:23 PM
> To: vtkusers at vtk.org
> Subject: [vtkusers] vtkImageReader and actual file access time
>
> Hi
>
> I am a complete newbie when it comes to streaming and caching data to
> save
> memory.
> So I was wondering if anybody could tell me when VTK exactly does the
> file
> reading and accesses the file from hard disk.
> Does it do piece by piece or it reads the whole image file and keeps it
> in
> cache ?
>
> Say, I have this code:
>
> 	vtkBMPReader *reader = vtkBMPReader::New();
> 	vtkImageData *data = vtkImageData::New();
> 	vtkImageViewer *viewer = vtkImageViewer::New();
>
> 	reader->SetDataSpacing(1.0,1.0,2.0);
> 	reader->SetDataOrigin(0.0,0.0,0.0);
> 	reader->SetFileName("image.bmp");
>
> 	viewer->SetInput(reader->GetOutput());
> 	viewer->SetColorWindow(255);
> 	viewer->SetColorLevel(127.5);
> 	viewer->Render();
>
> The actual reading off the hard disk happens when it hits the
> reader->GetOutput() or viewer->Render() ?
>
> Any input is appreciated
> Thanks
> Hamid
>
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