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Generic Image Library and premultiplied RGBA
by David Warkentin 28 Oct '08

28 Oct '08

I am trying to take advantage of the convolution capabilities of the GIL (with the numeric extension of course). I have some text that I render first using Cairo and then I pass the raw image data along to the code I'm using with the GIL with some simple glue code. This much of my code works great - I can write out a PNG using png_write_view after handing the data off to the library and it contains the rendered text as I would expect. There is a problem I've encountered, however, where the anti-aliasing pixels of the white text I have rendered against a transparent background appear dark and the blurred part of the text after convolving the image is also dark. I'm pretty sure this is due to the fact that the raw RGBA data I pass along already contains premultiplied alpha from Cairo. I'm guessing that the data is treated as if the alpha has not been premultiplied. I've been trying to figure out the best way to handle this situation and have had very little success in getting anything to work. I have recently been attempting to try one of the 2 things listed in this mailing list post by Lubomir Bourdev where he gives an example of approaches one could take to handle premultiplied RGBA data: http://lists.boost.org/Archives/boost/2006/10/112532.php. No matter what I try, however, I just keep getting endless compile errors and am probably going about it all wrong. Right now I've been trying to do something where I create types to represent premultiplied RGBA data: namespace boost { namespace gil { struct premultiplied_rgba_t : public rgba_t {}; typedef layout<premultiplied_rgba_t> premultiplied_layout_t; typedef pixel<bits8, premultiplied_layout_t> premultiplied_pixel_t; typedef image<premultiplied_pixel_t, false> premultiplied_image_t; } } ...so far this has just resulted in compile errors and I can't even begin to work on any kind of custom color conversion sort of thing that uses this new type yet (though actually I tried to once and couldn't make it work either). I'm guessing that what I need to do is either unmultiply the RGBA data first or I need to somehow get the library to work correctly with the premultiplied data. Can anyone help me figure out how to make this work? David Warkentin

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boost graph library with gcc 4.2 and later
by Moti Freiman 28 Oct '08

28 Oct '08

Hi All, I'm a newbie to boost and have a storng interest in the graph algorithms in boost. I tried to run both kolmogorov and edmund-karp examples and got many warnings due to deprecated conversions in the read_dimacs function When I tried to run these examples I got segmentation faults. Other simple program (from boost homepage) that I tried to compile and run, run well. Is there any known issue about using boost with gcc 4 and later? Thanks, Moti -- __ Moti Freiman, Ph.D Student. Medical Image Processing and Computer-Assisted Surgery Laboratory. School of Computer Science and Engineering. The Hebrew University of Jerusalem Givat Ram, Jerusalem 91904, Israel Phone: +(972)-2-658-5371 (laboratory) WWW site: http://www.cs.huji.ac.il/~freiman

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linking to boost signal library
by Jürgen Waser 28 Oct '08

28 Oct '08

I'm trying to incorporate BOOST signals into my vc8 project. I have built the dynamic libraries with the installer and set the project dependencies accordingly. I have written the simplest signal test code possible. The project compiles, but when linking I get the following error: 1>Linking... 1> Creating library c:\SIM\views\views\x64\Debug\viewsDebugx64.lib and object c:\SIM\views\views\x64\Debug\viewsDebugx64.exp 1>LINK : warning LNK4098: defaultlib 'LIBCMTD' conflicts with use of other libs; use /NODEFAULTLIB:library 1>Test.obj : error LNK2019: unresolved external symbol "public: __cdecl boost::signals::detail::call_notification::~call_notification(void)" (??1call_notification@detail@signals@boost@@QEAA@XZ) referenced in function "public: void __cdecl boost::signal1<void,bool,struct boost::last_value<void>,int,struct std::less<int>,class boost::function<void __cdecl(bool)> >::operator()(bool)" (??R?$signal1@X_NU?$last_value@X@boost@@HU?$less@H@std@@V?$function@$$A6AX_N@Z@2@@boost@@QEAAX_N@Z) 1>Test.obj : error LNK2019: unresolved external symbol "public: class boost::signals::detail::named_slot_map_iterator __cdecl boost::signals::detail::named_slot_map::begin(void)" (?begin@named_slot_map@detail@signals@boost@@QEAA?AVnamed_slot_map_iterator@234@XZ) referenced in function "public: void __cdecl boost::signal1<void,bool,struct boost::last_value<void>,int,struct std::less<int>,class boost::function<void __cdecl(bool)> >::operator()(bool)" (??R?$signal1@X_NU?$last_value@X@boost@@HU?$less@H@std@@V?$function@$$A6AX_N@Z@2@@boost@@QEAAX_N@Z) 1>Test.obj : error LNK2019: unresolved external symbol "public: class boost::signals::detail::named_slot_map_iterator __cdecl boost::signals::detail::named_slot_map::end(void)" (?end@named_slot_map@detail@signals@boost@@QEAA?AVnamed_slot_map_iterator@234@XZ) referenced in function "public: void __cdecl boost::signal1<void,bool,struct boost::last_value<void>,int,struct std::less<int>,class boost::function<void __cdecl(bool)> >::operator()(bool)" (??R?$signal1@X_NU?$last_value@X@boost@@HU?$less@H@std@@V?$function@$$A6AX_N@Z@2@@boost@@QEAAX_N@Z) 1>Test.obj : error LNK2019: unresolved external symbol "public: __cdecl boost::signals::detail::call_notification::call_notification(class boost::shared_ptr<class boost::signals::detail::signal_base_impl> const &)" (??0call_notification@detail@signals@boost@@QEAA@AEBV?$shared_ptr@Vsignal_base_impl@detail@signals@boost@@@3@@Z) referenced in function "public: void __cdecl boost::signal1<void,bool,struct boost::last_value<void>,int,struct std::less<int>,class boost::function<void __cdecl(bool)> >::operator()(bool)" (??R?$signal1@X_NU?$last_value@X@boost@@HU?$less@H@std@@V?$function@$$A6AX_N@Z@2@@boost@@QEAAX_N@Z) 1>c:\SIM\views\views\x64\Debug\viewsDebugx64.dll : fatal error LNK1120: 4 unresolved externals 1>Build log was saved at "file://c:\SIM\views\views\x64\Debug\BuildLog.htm" 1>views - 5 error(s), 1 warning(s) What could I be doing wrong? Thanks, Jurgen

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Building boost_1.34.1 on mac os X 10.5 64 bit.
by Alain Leblanc 28 Oct '08

28 Oct '08

I'm trying to build boost 1.34.1 on mac os X 64-bit. In a previous thread someone(Vladimir Prus) gave the following suggestion: ========================================== You need to pass architecture=x86 address-model=64 in addition to the above to bjam, or you may pass architecture=combined address-model=64 ========================================== and it looks like it was fine with boost 1.36. However when I try with boost 1.34.1 I get the following message: libs/test/src/execution_monitor.cpp:1: error: CPU you selected does not support x86-64 instruction set If I remove the achitecture=x86 option then it compiles, but the resulting libraries are not 64-bit, base on the output from file libbooost-XXX.dylib. Is there anything in the 1.34.1 version preventing me from compiling in 64-bit mode? I'm using gcc 4.0.1. Thanks, Alain

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[multi_index] doing insert() within iteration over equal_range() result?
by Prometheus Prometheus 28 Oct '08

28 Oct '08

Hi all, i have the following problem: i use multi_index like this std::pair<Plugins::pEvents::index::type::iterator,Plugins::pEvents::index::type::iterator> range; range = this->events.get().equal_range(boost::make_tuple(event,condition)); while(range.first!=range.second){ // CALL an event handler! this->callEventHandler(range.first); // << this shows just how it works, its not exactly my code ++range.first; } within the callEventHandler and its called functions its possible that the event handler wants to register new events which results to this: this->events.insert(eventdata); The problem is OR can be, that the insert modifies the indices which modify the range.first iterators and thus a ++range.first results in an invalid "next" element this makes sense and i think most of you know this and had this problem already Questions: Does anyone have a good idea/solution how to solve this situation correctly so that the range i received will be valid? i thought about using a second multi_index which holds the newly inserted events and after the WHILE it gets moved to the original events index, but this solution only moves the problem from one index to the second which helps a bit but doesnt really solve the problem, since i could miss newly inserted events another solution i thought of is like this range = ....equal_range(...) ; while( range.first!=range.second ){ Plugins::Event &ev = (Plugins::Event&)*range.first; // get first event if(ev.alreadycalled == false){ ev.alreadycalled = true; // this element doesnt have an index and so it shouldnt invalidate the iterator/index (right?) callEventHandler(); range= ...equal_range() ; // reinitialize the range and begin to search again! } else{ ++range.first; } } but the above solution gets slower the more events are available thx all _________________________________________________________________ Explore the seven wonders of the world http://search.msn.com/results.aspx?q=7+wonders+world&mkt=en-US&form=QBRE

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Problem calling bellman_ford_shortest_paths
by Tim Keitt 27 Oct '08

27 Oct '08

I'm prototyping some code that exposes an edge_list iterator interface to a database cursor. I've defined a forward_iterator using iterator_facade and can use that to create an edge_list graph. I'm running into a problem however calling bellman_ford_shortest_paths on the graph. I get boost_bellman_ford.cpp:18: error: no matching function for call to 'bellman_ford_shortest_paths(Graph&, position_t&, edge_weight_map, long long int*, double*)' The code leading up to that looks like: position_t N = getNumVertices(); edge_iterator iter; DEBUG_MESSAGE("Contructed iterator"); Graph g(iter, iter.end()); DEBUG_MESSAGE("Constructed edge list graph"); std::vector<double> distance(N, std::numeric_limits<double>::max()); distance[0] = 0.0; std::vector<position_t> parent(N); for ( position_t i = 0; i < N; ++i ) parent[i] = i; boost::bellman_ford_shortest_paths(g, N, edge_weight_map(), &parent[0], &distance[0]); The edge iterator is linked to the database cursor on construction. The problem I am guessing is in how I define the edge_weight_map. It looks like struct edge_weight_map { typedef cost_t value_type; typedef cost_t * reference; typedef edge_t key_type; typedef boost::readable_property_map_tag category; }; boost::property_traits<edge_weight_map>::value_type get(edge_weight_map map, boost::property_traits<edge_weight_map>::key_type key) { return key.cost; } It makes no sense for me to repeatedly query the database for the edge weight, so I attach it as a third field in the edge_descriptor. The get function merely returns the third component of the edge struct. I'm sort of assuming the way I am defining the edge_weight_map is the problem. Any insights? Also, I noticed the simply constructing the edge_list graph traverses the entire iterator range. Is there some copying going on? Can I override this behavior? THK -- Timothy H. Keitt http://www.keittlab.org/

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Reusing IOService Object
by Tim Pynegar 27 Oct '08

27 Oct '08

Hi, I'm having an issue starting then stopping and trying to restart a socket or rather the IOService that's being used to service that socket. The IOService and Socket are member's of my class that has a run method itself that is on a separate thread. In my class constructor the Socket is passed into the IOService constructor. The sequence is as follow's Socket.Open Socket.Bind Socket.async_recieve_from Thread Start ------ IOService.Run Socket.Close IOService.Stop ( the thread terminates due to the IOService.Run method completing ) Socket.Open Socket.Bind Socket.async_recieve_from Thread Start ------ IOService.Run This then return's immediately due to a "stopped" long in IOService ( on windows ) being set to 1. So my question is really am i trying to use these in the wrong way as in should i construct a new Socket and IOService for each time i want to start them or is there some way to reset the IOService to it's original state beyond calling IOService.Stop. Thanks, Tim.

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[test] testing protected/private methods out of test suits
by M. Siebeneicher 27 Oct '08

27 Oct '08

Hello boost-users, I tried to test protected/private class methods by declaring the test-case-class as a friend of the class-to-test. The test-case-class is defined by the macro BOOST_FIXTURE_TEST_CASE(T, F). That works fine as long as I encapsulate the test-case with BOOST_AUTO_TEST_SUITE(suite_name) and BOOST_AUTO_TEST_SUITE_END(). I'm not able to define the correct friend declaration, cause the compiler . Can someone give me hint, please? the code looks like this: // test-case-class.cpp namespace foo { namespace bar { BOOST_AUTO_TEST_SUITE(suite_name) struct F { class-to-test class_to_test_instance; } . . . BOOST_FIXTURE_TEST_CASE(test-case-class, F) { F.class_to_test_instance.i; . . . } . . . BOOST_AUTO_TEST_SUITE_END() }} class-to-test.cpp namespace foo { namespace bar { . . . class class-to-test { public: friend struct test-case-class; // that's wrong // No access to protected member i friend struct suite_name::test-case-class; // this is wrong, too: compiler error, can't find foo::bar::suite_name, .... protected: int i; . . . }; }} greetz, modbom -- GMX startet ShortView.de. Hier findest Du Leute mit Deinen Interessen! Jetzt dabei sein: http://www.shortview.de/wasistshortview.php?mc=sv_ext_mf@gmx

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asio:how to using iostream in blocking mode
by maosen.zhang 27 Oct '08

27 Oct '08

Hi all： In asio iostream client example: 27 tcp::iostream s(argv[1], "7777"); 28 std::string line; 29 std::getline(s, line); 30 std::cout << line << std::endl; Can I using iostream s in blocking mode? Which means std::getline will blocking to wait for data coming? Best wishes, maosen

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Link error using thread library
by Phillip Jones 27 Oct '08

27 Oct '08

I'm trying to compile an inherited program, and a not so well documented one at that. Anyway, using CodeBlocks and MinGW on a Windows system, and I'm stuck on this error: ..\obj\Debug\src\GameVisualizer.o||In function `WinMain':| src\GameVisualizer.cpp|39|undefined reference to `boost::thread_group::thread_group()'| ..\obj\Debug\src\GameVisualizer.o||In function `GLOBAL__D_io_mutex1':| src\GameVisualizer.cpp|51|undefined reference to `boost::thread_group::create_thread(boost::function0<void, std::allocator<boost::function_base> > const&)'| src\GameVisualizer.cpp|51|undefined reference to `boost::thread_group::~thread_group()'| ..\obj\Debug\src\GameVisualizer.o||In function `ZN6PlayerC1Ev':| )]+0xd)||undefined reference to `boost::mutex::do_unlock()'| )]+0xd)||undefined reference to `boost::mutex::do_lock()'| (it keeps going) I assume this is a linking problem. Here's what I've done so far, I'm hoping an outside pair of eyes can see what I'm missing. Used bjam to compile the thread libraries. bjam --build-dir "D:\bin.v2" --with-thread --toolset=gcc --build-type=complete stage Then, added "boost_thread-mgw34-mt-d-1_36" to the link libraries. Verified that the linker can find the library. Yet, still getting these errors. Any pointers would be much appreciated.

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