Hi Ed, yes, I have seen Dima's project. It is written for OpenCV v2, which is quite old and the API changed significantly. Since v4, they dropped the C interface which complicates matters since there are no direct PDL bindings to C++, unfortunately.
The problem I try to solve at the moment is to link two pieces of our code-base, one is a PDL:Graphics:Prima application, the other is tracking, which is only a tiny subset of OpenCV's capabilities. I've nailed the problem, I think. I was using Inline::Pdlpp which, apparently ignored my typemap file for OtherPars. Thus I work directly with a .pd and MakeMaker, it is recognised and code compiles. So, progress, yay! Now I'm struggling with passing around the object pointer. It never makes it to perl and back, unfortunately. I have created this repo here, please take a look. https://github.com/fantasma13/PDL-OCV Please take a look. Ingo On 3/4/2022 2:39 PM, Ed . wrote:
Hi Ingo (and Craig!), May I suggest this be tracked on https://github.com/PDLPorters/pdl/issues/362, which is presciently an issue (prompted by the PDLPorters GitHub wiki) prompting the creation of a PDL interface to OpenCV? You will see it links to Dima’s prototype https://github.com/dkogan/PDL-OpenCV, which will provide an excellent starting-point. You refer to Inline::C::Struct – I assume you mean https://metacpan.org/pod/Inline::Struct, now maintained by me. That would probably indeed make a good entity to pass around, though I would expect you’d need to make a typemap entry. The “subset” you refer to from the 2017 paper is simply whatever you choose, as GenericTypes; recent PDL supports all the primitive C types, from signed/unsigned char up to complex long double. Using the technique Craig pointed to is the PDL GSL bindings, see https://github.com/PDLPorters/pdl/tree/master/Libtmp/GSL/INTERP for a complete example. However you decide to proceed, I would urge you to indeed share your code, possibly on GitHub. It might even make sense for you to fork Dima’s repo and start from there? Please put the URL and any code so far on issue #362 :-) Best regards, Ed *From: *Ingo Schmid <mailto:ingo...@gmx.at> *Sent: *03 March 2022 17:40 *To: *Craig DeForest <mailto:defor...@boulder.swri.edu> *Cc: *pdl-devel <mailto:pdl-devel@lists.sourceforge.net>; perldl <mailto:pdl-gene...@lists.sourceforge.net> *Subject: *Re: [Pdl-devel] [Pdl-general] PP and c++ Hi would you be so kind of pointing me to a simple working example? My references look like memory addresses but seem to point to nowhere. Ingo On 3/3/2022 3:05 PM, Craig DeForest wrote: When I had to do things like that, I would generally cast the pointer to an IV and pass it around as an IV ref on the Perl side, then manually unwrap it when needed on the C side. This is the approach used by PDL itself. On Mar 3, 2022, at 7:55 AM, Ingo Schmid <ingo...@gmx.at> wrote: Hi, I'm working on PDL bindings (Inline:::Pdlpp) to the OpenCV (v4.5) tracking class. I have created a wrapper (see header below). I would now need to persistently store pointers to MatWrapper and TrackerWrapper - which are containers (structs) of the Mat and Tracker objects. At the moment, I have them declared in the auto_include code (struct TrackerWrapper * tw;). This would then prevent me from using multiple trackers. I therefore am looking of passing the pointer back and forth. I tried using OtherPars => 'TrackerWrapper * tw, MatWrapper * mw', .. this and a typemap file, it is referenced in the TYPEMAPS field. However, this results in unknown c type error TrackerWrapper when parsing the pd file. I think it is never used, following what is said here https://arxiv.org/pdf/1702.07753.pdf. Which subset of c-types are allowed? Is the approach reasonable and I am doing something wrong? What is the way to make a c struct persistent and accessible with perl/pp? There's Inline-C-Struct, does that work with pdl and if so, how? Any help is appreciated. I can share the full code (so far) upon request but it is work in progress. Ingo typemap: TYPEMAP TrackerWrapper T_PTR MatWrapper T_PTR tracker_wrapper.h: #ifdef __cplusplus extern "C" { #endif // struct cvType { int u8c3 ; int u8c1 ; int f32c3 ; int f32c1 ; } cvT; int tw_init(); //struct cvType cvT; typedef struct TrackerWrapper TrackerWrapper; struct TrackerWrapper * newTracker (int tracker_type); int deleteTracker (struct TrackerWrapper *); struct bBox{ int x; int y; int width; int height; }; typedef struct MatWrapper MatWrapper; struct MatWrapper * newMat (const int width, const int height, const int type, void * data); void * getData (struct MatWrapper * Mat); int setData (struct MatWrapper * Mat, const int type, void * data); int init_tracker(struct TrackerWrapper * Tr, struct MatWrapper * frame, const struct bBox * box ); int update_tracker(struct TrackerWrapper *, struct MatWrapper *, struct bBox * box); int show_tracker (struct MatWrapper * frame, struct bBox * roi) ; #ifdef __cplusplus } #endif _______________________________________________ pdl-general mailing list pdl-gene...@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/pdl-general
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