Hi all, I am trying to use GIL and face a problem. Here is the code : namespace boost { namespace gil { /// Extension a GIL pour gerer les pixels "double" ... typedef pixel< double, boost::gil::gray_layout_t > gray64_pixel_t; typedef image< gray64_pixel_t, false > gray64_image_t; typedef image< gray64_pixel_t, true > gray64_planar_image_t; //typedef image_view< gray64_pixel_t > gray64_view_t; } } int main ( int argc , char **argv) { typedef boost::mpl::vector< boost::gil::gray8_image_t, boost::gil::gray16_image_t, boost::gil::gray32_image_t, //boost::gil::gray64_image_t, boost::gil::rgb8_image_t, boost::gil::rgb16_image_t, boost::gil::rgb32_image_t > my_img_types; typedef boost::mpl::vector< boost::gil::gray8_view_t, boost::gil::gray16_view_t, boost::gil::gray32_view_t, //boost::gil::gray64_view_t, boost::gil::rgb8_view_t, boost::gil::rgb16_view_t, boost::gil::rgb32_view_t > my_view_types; if ( argc < 4 ) { usage(); return 1; } std::string input_filename( argv[1] ); std::string output_filename( argv[3] ); int channel_index; try { channel_index = boost::lexical_cast<int>( argv[2] ); } catch( boost::bad_lexical_cast &e) { std::cout << "bad_lexical_cast exception : " << e.what() << std::endl; return 1; } boost::gil::any_image<my_img_types> runtime_image; boost::gil::any_image_view<my_view_types> runtime_view; try { boost::gil::jpeg_read_image( input_filename , runtime_image ); runtime_view = boost::gil::nth_channel_view( const_view(runtime_image) , channel_index ); boost::gil::jpeg_write_view( output_filename , runtime_view ); } catch( std::exception &e ) { std::cout << e.what() << std::endl; return 1; } return 0; } I get an exception on this line : runtime_view = boost::gil::nth_channel_view( const_view(runtime_image) , channel_index ); However, when I write : boost::gil::jpeg_write_view( output_filename , boost::gil::nth_channel_view( const_view(runtime_image) , channel_index ) ); everything goes well. Where is my mistake ? Best regards, Olivier -- Olivier Tournaire MATIS - Institut Géographique National 73, Ave de Paris 94165 St Mandé cedex, France tel: (+33) 1 43 98 80 00 - 71 25 fax: (+33) 1 43 98 85 81
Hi Oliver, I don't get it to compile even when you put the nth_channel_view call inside jpeg_write_view for a simple reason. nth_channel_view needs the reference type of your any_image. But that's not possible since no one knows what image type the any_image actually is. You can cast your any_image to a specific image type using gil's variant::_dynamic_cast member. Then you can use nth_channel_view. Are you sure your code compiles? Let me know if you keep having troubles. Regards, Christian
2009/1/27 Christian Henning <chhenning@gmail.com>
Hi Oliver,
Hi Christian,
I don't get it to compile even when you put the nth_channel_view call inside jpeg_write_view for a simple reason. nth_channel_view needs the reference type of your any_image. But that's not possible since no one knows what image type the any_image actually is. You can cast your any_image to a specific image type using gil's variant::_dynamic_cast member. Then you can use nth_channel_view.
Are you sure your code compiles? Let me know if you keep having troubles.
Yes, my code compiles fine with boost 1.36. In attachement, maybe you could try. Regards, Olivier
Regards, Christian _______________________________________________ Boost-users mailing list Boost-users@lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users
-- Olivier Tournaire MATIS - Institut Géographique National 73, Ave de Paris 94165 St Mandé cedex, France tel: (+33) 1 43 98 80 00 - 71 25 fax: (+33) 1 43 98 85 81
Mhmm, somehow I screwed up. The following compiles fine now: int main ( int argc , char **argv) { typedef boost::mpl::vector< boost::gil::gray8_image_t, boost::gil::gray16_image_t, boost::gil::gray32_image_t, boost::gil::rgb8_image_t, boost::gil::rgb16_image_t, boost::gil::rgb32_image_t > my_img_types; typedef boost::mpl::vector< boost::gil::gray8_view_t, boost::gil::gray16_view_t, boost::gil::gray32_view_t, boost::gil::rgb8_view_t, boost::gil::rgb16_view_t, boost::gil::rgb32_view_t > my_view_types; boost::gil::any_image<my_img_types> runtime_image; boost::gil::any_image_view<my_view_types> runtime_view; runtime_view = boost::gil::nth_channel_view( const_view(runtime_image) , 0 ); return 0; } But when running I'm getting a bad_cast exception. What would you expect the retrieve from nth_channel_view call? I mean what can of image type is the correct one? Christian On Tue, Jan 27, 2009 at 3:31 PM, Olivier Tournaire <olitour@gmail.com> wrote:
2009/1/27 Christian Henning <chhenning@gmail.com>
Hi Oliver,
Hi Christian,
I don't get it to compile even when you put the nth_channel_view call inside jpeg_write_view for a simple reason. nth_channel_view needs the reference type of your any_image. But that's not possible since no one knows what image type the any_image actually is. You can cast your any_image to a specific image type using gil's variant::_dynamic_cast member. Then you can use nth_channel_view.
Are you sure your code compiles? Let me know if you keep having troubles.
Yes, my code compiles fine with boost 1.36. In attachement, maybe you could try.
Regards, Olivier
Regards, Christian _______________________________________________ Boost-users mailing list Boost-users@lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users
-- Olivier Tournaire MATIS - Institut Géographique National 73, Ave de Paris 94165 St Mandé cedex, France
tel: (+33) 1 43 98 80 00 - 71 25 fax: (+33) 1 43 98 85 81
_______________________________________________ Boost-users mailing list Boost-users@lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users
Thank you Christian. 2009/1/27 Christian Henning <chhenning@gmail.com>
Mhmm, somehow I screwed up. The following compiles fine now:
int main ( int argc , char **argv) { typedef boost::mpl::vector< boost::gil::gray8_image_t, boost::gil::gray16_image_t, boost::gil::gray32_image_t, boost::gil::rgb8_image_t, boost::gil::rgb16_image_t, boost::gil::rgb32_image_t > my_img_types;
typedef boost::mpl::vector< boost::gil::gray8_view_t, boost::gil::gray16_view_t, boost::gil::gray32_view_t, boost::gil::rgb8_view_t, boost::gil::rgb16_view_t, boost::gil::rgb32_view_t > my_view_types;
boost::gil::any_image<my_img_types> runtime_image; boost::gil::any_image_view<my_view_types> runtime_view;
runtime_view = boost::gil::nth_channel_view( const_view(runtime_image) , 0 );
return 0; }
But when running I'm getting a bad_cast exception. What would you expect the retrieve from nth_channel_view call? I mean what can of image type is the correct one?
Since it extracts one channel from an image, I thought I could retrieve one of the following : boost::gil::gray8_view_t, boost::gil::gray16_view_t or boost::gil::gray32_view_t. I am probably wrong, but is there a way to achieve such a task ? Regards, Olivier
Christian
On Tue, Jan 27, 2009 at 3:31 PM, Olivier Tournaire <olitour@gmail.com> wrote:
2009/1/27 Christian Henning <chhenning@gmail.com>
Hi Oliver,
Hi Christian,
I don't get it to compile even when you put the nth_channel_view call inside jpeg_write_view for a simple reason. nth_channel_view needs the reference type of your any_image. But that's not possible since no one knows what image type the any_image actually is. You can cast your any_image to a specific image type using gil's variant::_dynamic_cast member. Then you can use nth_channel_view.
Are you sure your code compiles? Let me know if you keep having
troubles.
Yes, my code compiles fine with boost 1.36. In attachement, maybe you
could
try.
Regards, Olivier
Regards, Christian _______________________________________________ Boost-users mailing list Boost-users@lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users
-- Olivier Tournaire MATIS - Institut Géographique National 73, Ave de Paris 94165 St Mandé cedex, France
tel: (+33) 1 43 98 80 00 - 71 25 fax: (+33) 1 43 98 85 81
_______________________________________________ Boost-users mailing list Boost-users@lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users
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-- Olivier Tournaire MATIS - Institut Géographique National 73, Ave de Paris 94165 St Mandé cedex, France tel: (+33) 1 43 98 80 00 - 71 25 fax: (+33) 1 43 98 85 81
Olivier, you can cast the any_image to any of the images you specified. Then you can easily apply the nth_channel_view() function. Something like this: typedef mpl::vector< gray8_image_t , rgb8_image_t >::type my_img_types_t; typedef nth_channel_view_type< rgb8_image_t::view_t >::type channel_view_t; any_image< my_img_types_t > runtime_image; rgb8_view_t v( view( runtime_image._dynamic_cast<rgb8_image_t>()) ); channel_view_t cv = nth_channel_view( v, 0 ); Hope that helps. Regards, Christian
Christian, Thank you for this code. However, I would like the extracted channel to be the same pixel type as the original runtime image. I guess it is possible since if I write the extracted channel view without storing it in a variable (see my first post), it works fine. Here it is: boost::gil::jpeg_read_image( input_filename , runtime_image ); boost::gil::jpeg_write_view( output_filename , boost::gil::nth_channel_view( view(runtime_image) , channel_index ) ); I just want to be as generic as possible and avoid "if ... else if ..." to get the right pixel type at runtime and thus perform the right dynamic_cast. Is it possible ? Regards, Olivier
Sorry Olivier, I tried some stuff but haven't made much progress. It still is riddle to me why the code compiles. Should it compile? I don't know. Hopefully Lubomir can fill in some time. Regards, Christian On Thu, Jan 29, 2009 at 12:44 PM, Olivier Tournaire <olitour@gmail.com> wrote:
Christian,
Thank you for this code. However, I would like the extracted channel to be the same pixel type as the original runtime image. I guess it is possible since if I write the extracted channel view without storing it in a variable (see my first post), it works fine. Here it is:
boost::gil::jpeg_read_image( input_filename , runtime_image ); boost::gil::jpeg_write_view( output_filename , boost::gil::nth_channel_view( view(runtime_image) , channel_index ) );
I just want to be as generic as possible and avoid "if ... else if ..." to get the right pixel type at runtime and thus perform the right dynamic_cast. Is it possible ?
Regards,
Olivier
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