ext-tray-v1: Add new protocol

Rendered

This protocol allows clients to display items in the compositor's tray areas. This serves multiple purposes:

• It removes the need for compositors to implement the status notifier protocols.
• It allows clients to display rich surfaces in tray popups. For example, a volume control application can embed volume controls directly in the popup.

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Some compositors outsource their tray area to privileged clients, for example, sway/swaybar. Such compositors can still use this protocol by additionally supporting a separate, privileged, protocol that allows them to embed such items into the privileged client (think zwp_text_input/zwp_input_method). That is out of scope for this protocol.

FAQ

1. Q: Why would the compositor advertise more than one tray?

   A: See the two comments starting at !355 (comment 2617998)

2. Q: Is this an alternative to the SNI protocols? How does this interact with the SNI protocols?

   A: !355 (comment 2620139)

Changelog

• 2024-10-20

  • Clarify language around configuration sequences.
  • Add ext_tray_item_v1.preferred_anchor event.
  • Add ext_tray_item_v1.preferred_gravity event.

Requirements for merging

• Review (1 required)
• Implementations (2 required)
  • Jay: https://github.com/mahkoh/jay/pull/296
  • wl-tray-bridge: https://github.com/mahkoh/wl-tray-bridge
• ACKs from members (2 required)