VolumeUp / VolumeDown actions via CGEventPost(kCGHIDEventTap) don't change system volume on macOS

[rockets-cn]

Description

Binding VolumeUp / VolumeDown (or MuteVolume) to a mouse button does not change the system volume, even though the hook correctly detects the button press and reports:

button → executing bound action button=Back action=Volume Up
button → executing bound action button=Forward action=Volume Down

Root cause

The Action::VolumeUp / VolumeDown variants call macos::post_key(0x48/0x49, none) which posts CGEventCreateKeyboardEvent events to kCGHIDEventTap. On macOS, the volume keys (kVK_VolumeUp=0x48, kVK_VolumeDown=0x49, kVK_Mute=0x4A) are system-defined keys — they are not standard HID keyboard usages and CGEventPost to kCGHIDEventTap does not trigger the system volume handler.

Verified workaround

Using osascript to change volume works reliably:

osascript -e "set volume output volume ((output volume of (get volume settings)) + 7)"

Suggested fix

Volume (and potentially media) keys need to be posted as NSSystemDefined events (event type 14 / NSSystemDefined, subtype 8) rather than via CGEventCreateKeyboardEvent. The NX key types are:

• NX_KEYTYPE_SOUND_UP = 0
• NX_KEYTYPE_SOUND_DOWN = 1
• NX_KEYTYPE_MUTE = 7

This is the same mechanism that post_media_key (line 828 of crates/openlogi-core/src/binding.rs) currently has as a stub — it also needs the NSSystemDefined approach.

Environment

• macOS 26.5.1 (Sequoia)
• OpenLogi v0.5.1
• Logitech MX Master 3S (Bluetooth LE)

[linear-code]

OLG-60

[rwkyyy]

confirming that it does not work in 0.6 as well.

[rwkyyy]

updated to 0.6.1 and did a full restart, none of the media actions work (play pause / stop / skip /etc.), including the volume ones.

[jonstuebe]

Took a shot at it. #184