Collaborative infinite-canvas boards for PhoenixKit.

Admins open Boards in the sidebar, create a board, and open it — an infinite Fresco canvas with the Etcher drawing layer (shapes, text, images). Multiple people on the same board see each other's edits, cursors, and presence in real time. Each board is one row in phoenix_kit_boards (its Fresco.Canvas document lives in the data jsonb column).

How it works

• Zero JS setup. PhoenixKit core already loads fresco.js + etcher.js and their hooks (the media annotation feature), so <Fresco.canvas> + <Etcher.layer> work in this module's pages out of the box. This module's own collaboration hooks are delivered by the board page itself, as LiveView runtime hooks — see PhoenixKitBoards.Web.RuntimeHooks. Nothing is asked of the host beyond depending on this module: no compiler entry, no script tag, no app.js import.

  js_sources/0 is still declared, so a host running core's :phoenix_kit_js_sources compiler keeps getting the bundle that way and LiveView prefers it. It is no longer load-bearing — which it silently was. A host that bundles dependency JS its own way got no hooks and no error: the board rendered and local edits saved, so the failure looked like "collaboration is broken" rather than "the JS never loaded".

• Collaboration rides the etcher document: each edit re-emits the full annotation list (etcher:annotations-changed); the LiveView persists it, broadcasts over PubSub, and peers apply the delta — no canvas remount.

• Presence + cursors ride plain PubSub on the board's topic.

Installation

# host mix.exs
{:phoenix_kit_boards, "~> 0.4"}

Then mix deps.get and mix phoenix_kit.update (creates the phoenix_kit_boards table). Enable it on the admin Modules page.