Simple collaborative free-drawing app. Powered by conflict-free replicated data type (CRDT) via yjs and y-websocket. For smooth drawing uses perfect-freehand.

To run locally:

## dev server
yarn dev

## ws server to forward messages
yarn ws

## both
yarn start

## e2e test
yarn e2e

• /views - UI components without much logic
• /containers - wraps some of the common logic, drives basic views
• /pages - combines containers and views
• /hooks - some custom logic extracted as a react hook
• /utils - simple helper functions. mostly pure
• App.tsx - keeps basic routing
• state.ts - facade for yjs relatedc stuff. state which gets distributed between participants

• generative unique boards with custom background colors
• multiple unique users in the same canvas boards
• setting a name
• unique line color per user
• 2 tabs identifies as 2 sessions of the same user
• displaying all users currently connected to the board
• zooming
• clearing a board

• dragging a canvas
• zooming by mousewheel
• different sizes of the line
• predefined shapes
• seing position of the other participants
• pinch to zoom on mobile

• scaling canvas based on devicePixelRatio have some issues
• using 2 fingers on mobile creates funny artifacts