CoreAudio High-level wrapper for Rust

This library provides a safe and easy-to-use abstraction over Apple's CoreAudio C API for macOS. It provides several types that are internally safely converted to C types.

For example, instead of using AudioObjectPropertyAddress, you have a simple AudioObjPropAddress struct that only accepts specific values. Take the following instance of AudioObjPropAddress:

let mut address = AudioObjPropAddress::new(
    PropertySelector::Device(AudioDevPropSelector::VolumeScalar),
    AudioDevPropScope::Output,
);

This is equivalent to the following:

#include <AudioToolbox/AudioToolbox.h>

AudioObjectPropertyAddress propertyAddress = {
    kAudioDevicePropertyVolumeScalar,
    kAudioDevicePropertyScopeOutput,
    0
};

The library doesn't expose every possible property selector, but if you need something, it's easy to add.

Features:

• Get the default input/output device
  • Get/set volume
    • Per-channel
  • Get/set mute state
  • Get/set name
  • Get channels
• Attach callbacks for events
  • Volume change
  • Default input/output device change

Example:

use coreaudio_hl::devices::AudioDevice;
use std::error::Error;

fn main() -> Result<(), Box<dyn Error>> {
    let device = AudioDevice::default_output()?;
    let name = device.name();
    let mute = device.muted()?;

    println!("Name: {name}");
    println!("Muted? {mute}");

    for channel in device.output_channels() {
        let volume = device.volume_for_channel(*channel)?;

        println!("Volume on channel #{channel}: {:.02}%", volume);
    }

    println!("Volume: {:.02}%", device.avg_volume()?);

    Ok(())
}

Name: WH-XB910N
Muted? false
Volume on channel #1: 0.37%
Volume on channel #2: 0.37%
Volume: 0.37%

Or, you can get an arbitrary property:

fn main() -> Result<(), Box<dyn Error>> {
    let device = AudioDevice::default_output()?;
    let mut _address = AudioObjPropAddress::new(
        PropertySelector::DEV_VOLUME_SCALAR,
        PropertyScope::DEV_OUTPUT,
    );

    // or...
    let mut address = AudioObjPropAddress::new(
        PropertySelector::Device(AudioDevPropSelector::VolumeScalar),
        PropertyScope::DEV_OUTPUT,
    );

    for channel in device.output_channels() {
        address.set_element(*channel);

        let volume = device.get_property::<String>(address)?;
        println!("Volume on channel #{channel}: {:.02}%", volume);
    }

    Ok(())
}

Note that this is highly not recommended. You should always use proper getters, as specified in the first example.