TradingVue.js
Hackable charting lib for traders. You can draw literally anything
...And if you miss the usability of TradingView.com in other open-source libraries and can't stand it, you are definitely in the right place! The process of adding a new indicator is simple, first you define your own data format (should be timestamped though) and display settings. Customizable colors and fonts. Quite fast (works even with 3 mil candles). Scripts (make your own indicators). Simple API for making new overlays. Custom drawing tools. Non-time based charts (e.g. Renko).