[Openexr-devel] Changing the Header

[Barnaby Robson]

I noticed how easy it is to get the compression attribute from the header with

the Imf::Header function compression() but there seems to be an issue when setting compression

in a pre-existing header.

 

I am using the insert function like so to set Piz Compression (which, by the way, is amazing)

 

header.insert ("compression", Imf::CompressionAttribute (Imf::PIZ_COMPRESSION));

 

which is really just shorthand for saying this ...

 

// const Imf::Compression comp = Imf::PIZ_COMPRESSION;

// Imf::TypedAttribute<Imf::Compression> attr(comp);

// header.insert("compression", attr);

 

if I type it either way I get a long warning in .NET about a dynamic cast

 

C:\dev\rd\libs\3rdparty\OpenEXR\vc\vc7\include\IlmImf\ImfAttribute.h(355) : warning C4541: 'dynamic_cast' used on polymorphic type 'Imf::Attribute' with /GR-; unpredictable behavior may result

C:\dev\rd\libs\3rdparty\OpenEXR\vc\vc7\include\Imath\ImathVec.h(234) : while compiling class-template member function 'const Imf::TypedAttribute<T> *Imf::TypedAttribute<T>::cast(const Imf::Attribute *)'

with

[

T=Imf::Compression

]

C:\Program Files\Microsoft Visual Studio .NET 2003\Vc7\include\xstring(521) : while compiling class-template member function 'Imf::TypedAttribute<T>::TypedAttribute(void)'

with

[

T=Imf::Compression

]

C:\Program Files\Microsoft Visual Studio .NET 2003\Vc7\include\xmemory(156) : while compiling class-template member function 'Imf::TypedAttribute<T>::~TypedAttribute(void)'

with

[

T=Imf::Compression

]

C:\dev\rd\libs\3rdparty\OpenEXR\vc\vc7\include\IlmImf\ImfCompressionAttribute.h(54) : see reference to class template instantiation 'Imf::TypedAttribute<T>' being compiled

with

[

T=Imf::Compression

]

-----------------------------------------

 

I can stop this warning by adding the /GR flag to my compiler. The option (/GR) adds code to check object types at run time.

I was worried that this might slow down the code though ..

 

What do you guys do and what do you suggest ?

 

Thanks

 

barnaby