Rust opencv demo

main.rs

/*
Author: Rajesh Pachaikani
Contact: [email protected]
*/

use opencv::{highgui, prelude::*, videoio, Result};

fn main() -> Result<()> {
    let mut cam = videoio::VideoCapture::new(0, videoio::CAP_ANY)?;
    highgui::named_window("window", highgui::WINDOW_FULLSCREEN)?;
    let mut frame = Mat::default();
    loop{
        cam.read(&mut frame)?;
        highgui::imshow("window", &frame)?;
        let key = highgui::wait_key(1)?;
        if key == 113{
            break;
        }
    }

    Ok(())
}

Saw your post on reddit and you asked for feedback. Nice getting started with OpenCV and Rust btw!
Regarding your code snippet and possible suggestions I would consider adapting the following:

use opencv::{highgui, prelude::*, videoio, Result};

fn main() -> Result<()> {
    let mut cam = videoio::VideoCapture::new(0, videoio::CAP_ANY)?;
    let mut frame = Mat::default();
    
    // moving wait_key(1) in the loop header allows for easy loop breaking if a condition is met (0 corresponds to 'ESC', 113 would be 'Q'
    while highgui::wait_key(1)? < 0 {
        cam.read(&mut frame)?;

        // check whether VideoCapture still has frames to capture
        if !cam.grab()? {
            println!("Video processing finished");
            break
        }

        highgui::imshow("window", &frame)?;
    }

    Ok(())
}

I am very new to Rust. I didn't knew I can use while loop like that in Rust. Thank you for your inputs.

Thanks @rajeshpachaikani. 😄

Just getting started with Rust and your script helped out.

Instructions

Hi, for anyone trying to run the script above, you can refer to what I did to get the above script running after having installed Rust on my work station.

Environment 📖

Ubuntu 22.04

1. Set up cargo workspace

cd $HOME
cargo new --bin rust-opencv

Build 🔨

2. Include opencv dependencies under newly generated Cargo.toml:

cd $HOME
cd rust-opencv

Your Cargo.toml should look what is shown below:

[package]
name = "rust-opencv"
version = "0.1.0"
edition = "2021"

# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

[dependencies]
opencv="0.60.0" # <---

Run 🏃‍♂️

3. Build cargo workspace:

cd ~/rust-opencv
cargo run

The web camera that you have connected should now be displayed using the OpenCV GUI.

Issues 🐛

If you encountered an error similar to what is shown below:

warning: could not execute `llvm-config` one or more times, if the LLVM_CONFIG_PATH environment variable is set to a full path to valid `llvm-config` executable it will be used to try to find an instance of `libclang` on your system: "couldn't execute `llvm-config --prefix` (path=llvm-config) (error: No such file or directory (os error 2))"

error: failed to run custom build command for `clang-sys v1.4.0`

You can resolve this issue by running the command below:

sudo apt-get install clang libclang-dev

failed to run custom build command for opencv v0.78.0
-- Error while running this code

Issues 🐛

If you encountered an error similar to what is shown below:

warning: could not execute `llvm-config` one or more times, if the LLVM_CONFIG_PATH environment variable is set to a full path to valid `llvm-config` executable it will be used to try to find an instance of `libclang` on your system: "couldn't execute `llvm-config --prefix` (path=llvm-config) (error: No such file or directory (os error 2))"

error: failed to run custom build command for `clang-sys v1.4.0`

You can resolve this issue by running the command below:

sudo apt-get install clang libclang-dev

This rust tutorial is mindblowing. Thanks a lot.
If you encountered a libclang.dylib' (no such file) error on macos.
Then install xcode and opencv

brew install opencv

and link the lib

sudo ln -s /Library/Developer/CommandLineTools/usr/lib/libclang.dylib /usr/local/lib