opencv-rust VS case-studies

https://github.com/twistedfall/opencv-rust makes it evident that they do try to support using a prebuild system-opencv. Maybe it is not correctly recognized?

opencv

The de facto solution for smart image processing is to use a computer vision library, such as opencv, which has experimental rust bindings: https://github.com/twistedfall/opencv-rust

There is an OpenCV bindings crate. This example might be what you're after https://github.com/twistedfall/opencv-rust/blob/master/examples/video_capture.rs

For example, this is the build script of the opencv bindings: https://github.com/twistedfall/opencv-rust/blob/master/build.rs

I’m trying to get around a known build issue—it would be great for it to be fixed upstream, but I don’t have any control over it except for setting OUT_DIR during its compilation.

I've been using https://github.com/twistedfall/opencv-rust a lot lately and it's really fantastic, they've done a great job matching up with how C++ works, so there are definitely good examples out there.

I never tried it, but the OpenCV bindings might work.

I thought it was going to be unsafe because of how Mat is implemented (more information here). ... I tested it and it should be fine memory-wise. My thought was that the code below was going to be allowed to compile.

Luckily there is a workaround to emulate such a definition, which dtolnay discovered and explained here: https://github.com/dtolnay/case-studies/tree/b9802f6df8dc8e54970b83fb9af6df923b46abf5/unit-type-parameters.

I think they are talking about this one trick which the devs don't want you to know about. Note that while it looks like specialization, it works only in a few very limited cases and is quite fragile, so it's a hack, not a substitute for the real feature.

Also I suggest his case studies repo since you are looking at what is possible: https://github.com/dtolnay/case-studies

/u/dtolnay has a great case studies repository.

Once you have the basics down, read dtolnay's case studies. They show how to do advanced stuff with easy macros.

If you were writing your own println macro, you might be able to get away with this kind of hack: https://github.com/dtolnay/case-studies/blob/master/autoref-specialization/README.md

You can use "Autoref-based stable specialization" or use/mimic the impls crate.

With a subset of specialization likely riding the trains soon and a workaround available, why would you give up?

this works since values and types are in different namespaces (see: Rusts Universes or dtolnay's Case Study about "Unit struct with type parameters")

To do this with traits you would need specialization but since you are using macros you should be able to use "Autoref-based stable specialization". Here is a playground which uses the latter approach to implement the wanted macro without using any nightly features.