Hi, I have managed to pass data from pdl to OpenCV and back by copying. I would have preferred some kind of mapping but that is not working, see below. So, technically, there is a working interface to OpenCV., at least for grayscale floats.
ee the t/basic_opencv.t for what it can do at the moment. I will get the object tracking working next. Video in/output is also planned, as is support for other data types, at least 32fC1/3 8UC1/3 and basic imshow support. I guess I will be able to generate simple opencv function support through templates, see ufunc in poencv.pd (yes, I stole that from ops.pd). So you can use it, but you would still need to write wrapper code encapsulating OpenCV. I have tried - and failed - using Inline::CPP and a simple #include <opencv2/core.hpp> which throws all sort of errors. Most of all redefinitions like seed or cv. Try compiling this code (g++) and you will see. #include "EXTERN.h" #include "perl.h" #include "XSUB.h" #include "INLINE.h" #undef seed using namespace std; #include <opencv2/core.hpp> On 3/16/2022 4:55 PM, Ingo Schmid wrote: > > Hi Ed, > > thank you. I have made some progress but getting data from a cv:Mat to > a PDL is a mystery still. If you could look at the code I would > appreciate it. I have a valid pointer to the data, either in C or > perl, but how to make a piddle use that as it's dataref is beyond me. > > > Ingo > > On 3/15/22 21:50, Ed . wrote: >> >> Hi Ingo, >> >> >> >> Glad you’re making progress! >> >> >> >> The problem you’re having here is that you’re somewhat mixing your >> metaphors. For now, PDL mainly uses SVs for storing data. The >> “datasv” member of the struct points at the data SV, and the “data” >> member is set to point at its PV. Within e.g. the readdata function, >> a local C variable for the data pointer of ndarray “m” is created >> called “m_datap”, which gets updated during broadcasting. The “$P(m)” >> macro in PP expands to “m_datap”. >> >> >> >> As you may now appreciate, assigning to that is not going to have any >> long-term effect once the function returns. You’re going to need a >> different approach. One that will operate somewhat, but isn’t the >> correct answer, is to assign to “$PDL(m)->data” instead. But you’re >> going to need to do memory-management properly, otherwise you’ll get >> segfaults and/or leak memory. >> >> >> >> A more direct way to achieve the aim, staying with the SV model, is >> to enhance your MatWrapper Perl object (using XS) to be able to >> return its data (and dimensions as well), and make your get_data be >> pure-Perl that extracts dims, types and data from the MatWrapper in >> Perl-land, and uses PDL methods setdims, set_datatype, and >> get_dataref/upd_data to create an ndarray. >> >> >> >> Best regards, >> >> Ed >> >> >> >> *From: *Ingo Schmid <mailto:ingo...@gmx.at> >> *Sent: *15 March 2022 19:52 >> *To: *perldl <mailto:pdl-general@lists.sourceforge.net> >> *Subject: *[Pdl-general] set pointer to data (PP) >> >> >> >> Hi, >> >> I would like to update the pointer to piddle data. I've got a C function >> >> void * getData(MatWrapper * mw); >> >> that returns the pointer to opencv Mat data. I declare the piddle $m >> with the right size and data type in PMCode. Now, I can successfully say >> >> void * data = getData($COMP(mw)); >> >> $P(m)=data; >> >> and print the right numbers in C. >> >> printf("m (48,48) %f\n",$m(k=>48,l=>48)); # 50.842896 - correct. >> >> However, after returning to perl, $m(48,48) is 0 and get_dataref >> shows the wrong datdress. What's the trick to make this permanent? >> >> Ingo >> >> == >> >> pp_def ('get_data', >> Pars=>'[o] m(k,l);', >> OtherPars=>'MatWrapper * mw', >> Code=>pp_line_numbers(__LINE__, >> ' >> PDL_Indx ks = $SIZE(k); >> PDL_Indx ls = $SIZE(l); >> int x = cols($COMP(mw),-1); >> int y = rows($COMP(mw),-1); >> printf ("x %d : ks %d / y %d : ls %d ",x,ks,y,ls); >> if ((x == ks) && (y == ls)) >> { >> void * dat; >> dat = getData($COMP(mw)); >> $P(m)=dat; >> } else { >> $CROAK("Matrix size does not match!\n"); >> } >> printf("m (48,48) %f\n",$m(k=>48,l=>48)); >> '), >> PMCode=>pp_line_numbers(__LINE__, >> ' >> sub get_data { >> my ($mw,$p) = @_; >> unless (ref ($p) =~ "PDL") { >> say "rows $mw->rows"; >> $p=zeroes(float,$mw->cols,$mw->rows); >> } >> _get_data_int($p,$$mw); >> say "(get_data) 48,48: ",$p->slice("48","48"); >> $p->upd_data; >> say "(get_data) 48,48: ",$p->slice("48","48"); >> $p->transpose; >> } >> ',), >> Doc=><<"EOD", >> >> =head2 set_data - update data of a Mat object. Size and type should >> match. >> >> EOD >> >> ); >> >> >> >> >> > > > _______________________________________________ > pdl-general mailing list > pdl-general@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/pdl-general
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