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<div class="moz-cite-prefix">On 01.05.2013 16:50, Berk Geveci wrote:<br>
</div>
<blockquote
cite="mid:CAE32kpV9z0sU+2rZGLZw3J3vMpNvko4GyDJqQVnXFfy-SkDVZw@mail.gmail.com"
type="cite">
<div dir="ltr">If you want the output of an algorithm to stick
around after deleting it, you need to call Register() on the
data object. Something like:
<div><br>
</div>
<div><font style="font-size:13px" face="Courier New, Courier,
monospace"> vtkSmartPointer<vtkReader1> Reader1 =
vtkSmartPointer<vtkReader1>::New()</font><br
style="font-family:arial,sans-serif;font-size:13px">
<font style="font-size:13px" face="Courier New, Courier,
monospace"> // set filename and update reader1</font><br
style="font-family:arial,sans-serif;font-size:13px">
<font style="font-size:13px" face="Courier New, Courier,
monospace"> vtkDataSet * MyDataSet =
Reader1->GetOutput();</font><br
style="font-family:arial,sans-serif;font-size:13px">
</div>
<div style=""><font style="font-size:13px" face="Courier New,
Courier, monospace"> MyDataSet->Register(0);</font></div>
</div>
<div class="gmail_extra"><br>
<br>
</div>
</blockquote>
<br>
Yes, but wouldn't you have to delete MyDataSet manually?<br>
Why not using SmartPointers also for MyDataSet? From what I
understand after reading
<a class="moz-txt-link-freetext" href="http://www.vtk.org/Wiki/VTK/Tutorials/SmartPointers">http://www.vtk.org/Wiki/VTK/Tutorials/SmartPointers</a> , the following
code should also work and memory is released automatically when the
last pointer pointing to the data goes out of scope:<br>
<br>
vtkSmartPointer<vtkDataSet> MyFilter::GetMyDataSet( ... )<br>
{<br>
vtkSmartPointer<vtkDataSet> MyDataSet;<br>
<br>
if(SomeConditions)<br>
{<br>
vtkSmartPointer<vtkReader1> Reader1 =
vtkSmartPointer<vtkReader1>::New()<br>
// set filename and update reader1<br>
MyDataSet = Reader1->GetOutput();<br>
}<br>
else<br>
{<br>
vtkSmartPointer<vtkReader2> Reader2 =
vtkSmartPointer<vtkReader1>::New()<br>
// set filename and update reader2<br>
MyDataSet = Reader2->GetOutput();<br>
}<br>
<br>
return MyDataSet;<br>
}<br>
<br>
vtkSmartPointer<vtkDataSet> MyDataSet = GetMyDataSet( ... );<br>
<br>
<br>
Or did I miss something?<br>
<br>
Regards,<br>
Dominique<br>
<br>
<br>
<blockquote
cite="mid:CAE32kpV9z0sU+2rZGLZw3J3vMpNvko4GyDJqQVnXFfy-SkDVZw@mail.gmail.com"
type="cite">
<div class="gmail_extra">
<div class="gmail_quote">On Tue, Apr 30, 2013 at 5:14 PM,
Sunrise <span dir="ltr"><<a moz-do-not-send="true"
href="mailto:helios.corona@gmail.com" target="_blank">helios.corona@gmail.com</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div bgcolor="#FFFFFF" text="#000000">
<div>Thanks for the answer, Berk.<br>
<br>
I have a follow up question, which I guess I can solve
it with strong pointers. Assume the following<br>
<br>
<font face="Courier New, Courier, monospace">vtkDataSet
* MyFilter::GetMyDataSet(...)<br>
{<br>
</font>
<blockquote><font face="Courier New, Courier, monospace">if(SomeConditions)</font><br>
<font face="Courier New, Courier, monospace">{</font><br>
<font face="Courier New, Courier, monospace">
vtkSmartPointer<vtkReader1> Reader1 =
vtkSmartPointer<vtkReader1>::New()</font><br>
<font face="Courier New, Courier, monospace"> //
set filename and update reader1</font><br>
<font face="Courier New, Courier, monospace">
vtkDataSet * MyDataSet = Reader1->GetOutput();</font><br>
<font face="Courier New, Courier, monospace">}</font><br>
<font face="Courier New, Courier, monospace">else</font><br>
<font face="Courier New, Courier, monospace">{</font><br>
<font face="Courier New, Courier, monospace">
vtkSmartPointer<vtkReader2> Reader2 =
vtkSmartPointer<vtkReader1>::New()</font><br>
<font face="Courier New, Courier, monospace"> //
set filename and update reader2</font><br>
<font face="Courier New, Courier, monospace">
vtkDataSet * MyDataSet = Reader2->GetOutput();</font><br>
<font face="Courier New, Courier, monospace">}</font><br>
<br>
<font face="Courier New, Courier, monospace">//
MyDataSet is out of scope here!<br>
// Even if I remove if condition, they will be out
of scope outside of this function.<br>
<br>
return MyDataSet;<br>
</font></blockquote>
<font face="Courier New, Courier, monospace">}<br>
</font><br>
I want to make both <font face="Courier New, Courier,
monospace">reader1</font> and <font face="Courier
New, Courier, monospace">reader2</font> become
SmartPointers. Otherwise I have leak. At compile time I
do not know how the code will end, only at the run time
it make the decision. So I do not know when to delete <font
face="Courier New, Courier, monospace">reader1</font>
and <font face="Courier New, Courier, monospace">reader2</font>.<br>
<br>
I do not want to use descrutor too. there are more
readers than the sample code that I put here, so at
compile time the destructor do not know how many <font
face="Courier New, Courier, monospace">reader1</font>
and/or <font face="Courier New, Courier, monospace">reader2</font>
has been declared in order to delete them manually. So,
I prefer to declare all of them with Smart Pointers.<br>
<br>
But here is the problem: <font face="Courier New,
Courier, monospace">reader1</font> and <font
face="Courier New, Courier, monospace">reade2</font>
are in clauses of If condition, and they are in a
function outside of RequestData. So they will go out of
scope.<br>
<br>
If using a strong pointer fix this problem, how can I
apply a strong pointer on <font face="Courier New,
Courier, monospace">MyDataSet</font> in VTK?<br>
<br>
Again, thank you very much.<br>
<br>
-Sia
<div>
<div class="h5"><br>
<br>
<br>
On 04/29/2013 08:20 AM, Berk Geveci wrote:<br>
</div>
</div>
</div>
<div>
<div class="h5">
<blockquote type="cite">
<div dir="ltr">It does a shallow copy. The
information object holds a strong reference to the
data object so
<div><br>
</div>
<div><span>outputInfo->Set(</span><span>vtkDataObject::DATA_OBJECT(),</span><span>MyDataSet);</span><br>
</div>
<div><span><br>
</span></div>
<div><font face="arial, helvetica, sans-serif">so
it will increment the reference count of
MyDataSet preventing it from going out of
scope.</font></div>
<div><font face="arial, helvetica, sans-serif"><br>
</font></div>
<div><font face="arial, helvetica, sans-serif">-berk</font></div>
</div>
<div class="gmail_extra"><br>
<br>
<div class="gmail_quote">On Sun, Apr 28, 2013 at
11:41 AM, Sunrise <span dir="ltr"><<a
moz-do-not-send="true"
href="mailto:helios.corona@gmail.com"
target="_blank">helios.corona@gmail.com</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0
0 0 .8ex;border-left:1px #ccc
solid;padding-left:1ex">
<div bgcolor="#FFFFFF" text="#000000"> I am
wondering if the "<font face="Courier New,
Courier, monospace">Set</font>" method in
<font face="Courier New, Courier, monospace">vtkInformation</font>
class performs a deep-copy or shallow-copy
when I set a <font face="Courier New,
Courier, monospace">DATA_OBJECT</font>
into it?<br>
<br>
Suppose I have some <font face="Courier
New, Courier, monospace">vtkDataSet</font>
and I want to append them into <font
face="Courier New, Courier, monospace">outputInfo</font>
of a filter inside its <font face="Courier
New, Courier, monospace">RequestData</font>
method. <br>
<br>
<font face="Courier New, Courier, monospace">int
Filter1::RequestData(...)<br>
{<br>
vtkSmartPointer<vtkSomeReader>
myreader =
vtkSmartPointer<vtkSomeReader>::New();<br>
...<br>
vtkDataSet *MyDataSet =
Reader->GetOutput();<br>
outputInfo->Set(vtkDataObject::DATA_OBJECT(),MyDataSet);<br>
...<br>
}</font><br>
<br>
at the end of <font face="Courier New,
Courier, monospace">RequestData</font>,
both the pointer <font face="Courier New,
Courier, monospace">myreader</font> and
its data on the heap would be out of scope.
Since I made them smart pointers, both
pointer "myreader" and the data on the heap
will be deleted (right?).<br>
<br>
But in the next filter of the pipeline (say
Filter2 is connected to Filter1), I can
receive the data in <font face="Courier
New, Courier, monospace">inputInfo</font><br>
<br>
<font face="Courier New, Courier, monospace">int
Filter2::RequestData(...)<br>
{<br>
...<br>
...
inputInfo->Get(vtkDataObject::DATA_OBJECT());<br>
}</font><br>
<br>
I am wondering why still I can get the data,
since data deferenced by <font
face="Courier New, Courier, monospace">MyDataSet</font>
in previous filter no longer exists?<br>
<br>
Does <font face="Courier New, Courier,
monospace">vtkInformation::Set</font>
perform a deep copy?<br>
<br>
Thank you.<br>
</div>
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<pre class="moz-signature" cols="72">--
Dominique Töpfer, Dipl.-Inform.
Institute of Medical Physics
University of Erlangen</pre>
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